Poster Session WP3 11:15 - 12:00 Wednesday, 28th April, 2021 Presentation type Poster

45 minutes individual presenter Q&A

WP3.01 Single asperity sliding abrasion testing of bulk metals and coatings

Michiel Corryn, Haithem Ben Hamouda, Ansbert De Cleene ArcelorMittal Global R&D Gent, Belgium

Abstract

Single asperity sliding abrasion testing, also known as scratch testing, is commonly used to gain fundamental knowledge of wear processes. Such processes are often complicated to analyze or reproduce in the context of material testing. Therefore, reducing the complexity to the point of single contact is a repeatable way to characterize material behaviour. This is mainly due to the limited number of parameters to control (indentation force, speed and indenter geometry). In this paper, scratch testing will be combined with several in-situ techniques to obtain as much data as possible from one test. This will be illustrated in two case studies: producing a wear mechanism map for bulk materials, and ranking metallic coatings by their scratch resistance. A selection of bulk materials was scratched with a series of scratches using an increasing normal load. Inline microscopy in combination with full 3D scratch topography allowed to examine wear mechanism, scratch depth and scratch width. As such a wear mechanisms map was made that plots the observed wear mechanisms in function of the material hardness and the degree of penetration of the scratch. This demonstrated the difference in behaviour across different load levels per material. Coatings can be analyzed with a scratch test as well to assess the adhesion and cohesion of a coating. Here a linear increasing load is applied across the scratch to find the critical point at which the coating starts to fail. It can be tricky however to pinpoint this after the test due to severe damage to the coating. The combination of Acoustic Emission-analysis and inline microscopy allow for an exact determination of the critical loads. As such different coatings can be ranked accordingly.

Keywords abrasion wear mechanism wear test scratch test WP3.02 Combined effect of abrasive particle size distribution and ball material on the wear coefficient in micro-scale abrasive wear tests

Pâmella Esteves1, Vanessa Seriacopi2, Marcelo de Macêdo3, Roberto Souza1, Cherlio Scandian3 1Escola Politécnica da Universidade de São Paulo, Brazil. 2Instituto Mauá de Tecnologia, Brazil. 3Universidade Federal do Espírito Santo, Brazil

Abstract

Micro-abrasive wear tests were carried out to analyze the combined effect of abrasive particle size distribution and ball material on the wear coefficient. Different particle size distributions were obtained by mixing different fractions of two silicon carbide (SiC) abrasive powders, having average particle sizes of 6.0 μm and 14.4 μm. Tests were conducted using two different normal loads, 0.2 and 0.4 N, AISI 1020 steel samples and balls made of AISI 52100 martensitic steel, AISI 304 austenitic stainless steel, polyurethane rubber and zirconia-alumina. Worn surfaces were analyzed with Scanning Electron Microscopy (SEM) and by optical profilometry, allowing detection of wear modes (“rolling abrasion” or “grooving abrasion”). Results have indicated that a change in ball material, with consequential modification in the ratio between the hardness of the body and the counter- body, enabled different behaviors of the wear coefficient with the variation of the granulometric distribution. Such differences are due to the ability of the particles to be embedded and dragged into contact. When using balls made of AISI 52100 martensitic steel and AISI 304 austenitic stainless steel, the lowest wear coefficients were mainly obtained with the mixture with 50% and 20%, in mass, of the powder with the largest average particle diameter, respectively. The use of a highly elastic polyurethane rubber ball resulted in no change in the wear coefficient with the different powder mixtures. On the other hand, with zirconia-alumina balls, an increase in the wear coefficient was observed with the increase of the mass fraction of the powder with the largest abrasive particle size.

Keywords

Micro-scale abrasion Particle size distribution Ball material Wear coefficient WP3.03 Investigation of flexural strength and abrasion resistance improvement by using micron size glass beads and alumina nanoparticles reinforcement of epoxy matrix

Dorina Mihut, Arash Afshar, David Carter, Gregory Baker, Nicholas Cordista Mercer University, USA

Abstract

Epoxy based composite materials are widely used in many fields including aerospace, automotive industry and marine applications due to their good mechanical properties and low weight. The current research is investigating the effects of using glass beads micron size particles (9-13 micrometer) or alumina nanometer size particles (50 nm) as epoxy matrix reinforcements on the mechanical properties. Samples were produces using 0, 5, 10 and 15 % glass beads or similar percentages alumina nanoparticles that were well dispersed in the epoxy matrix. The degree of dispersion was evaluated using the Scanning Electron Microscopy (SEM). Some of the samples were then exposed to standardized accelerated weathering tests (cycles of UV radiation, high temperature and moisture) using a Q-Lab QUV equipment. The effects of the glass beads and alumina nanoparticles epoxy embedment was explored by conducting standardized flexural tests (Mark-10 tensile testing equipment) and abrasion tests (Taber abrasion tester equipment). Similar tests were performed on samples exposed to harsh environmental conditions. Different models were developed to theoretically describe the mechanical behavior of the epoxy composites. It was observed that flexural strength performance was not enhanced by the introduction of glass beads or alumina nanoparticles. However, the abrasion resistance was improved by using both materials with higher improvement observed in the case of alumina nanoparticles.

Keywords

Epoxy based composites glass beads microparticles alumina nanoparticles weathering test WP3.04 Biological lubrication at articulating cartilage in moderate risk domain: PRG4/HA starved diffusion

Pankaj Tomar IGDTUW/GGSIPU, India

Abstract

SARS-COV-2 pandemic outbreak reinforced cognitive load for innovation at science policy humanity interface to mend acquaintance with nature for synergistic general health. Diversity of biology, gender diversity, cultural diversity viz. Nutrition, lifestyle, rational expended energy, psychosocial parameters prevent degradation of extracellular matrix at boundary lubrication regime. PRG4, HA, and ECM are the building blocks of lubrication regimes under operating conditions inherently regulate palpable interfacial antifriction. Synovial lubrication is shear thickning phenomenon profoundly under elevated speed adequate lubricant is pumped at articulating joint for integrity of cartilage. The paper carried mechanism and mechanics of starved biological lubrication, descriptive literature, L4-L5 sketches of a subject, academic survey of leading hospitals with perception of fundamental causes for surgery, and chemistry of fuel oxidation.

Keywords

ECM Oxidation Boundary lubrication Biomechanical WP3.05 Characterization of wear debris components from carbon-carbon composite brakes

Matthew Noor1,2, Peter Filip1, Yanmei Piao3, Angela Hight Walker2, Jeffrey Fagan2, Neil Murdie4 1Southern Illinois University, USA. 2National Institute of Standards and Technology, USA. 3Honeywell International, USA. 4Honeywell International,, USA

Abstract

Carbon-carbon (C-C) composites are often used as friction and brake materials due to their high strength, low density, excellent frictional properties, high thermal conductivity and high heat capacity. When worn, C-C composites produce particulate wear debris. The fine wear debris particles then form a layer on the wear surface, known as a friction film layer, which has the potential to change the overall frictional performance of the system. The size, shape and chemistry of these wear debris particles and friction layers can give information about the mechanisms of wear in the composite and the effects of temperature, humidity, oxidation and other chemical modifications that can occur depending on the wear environment. However, this analysis is rather difficult to perform due to the wide range of particle size, from small primary particles to large aggregates. The chemical and material similarities of the carbon fiber and matrix further complicates decoupling the effects of the different components of wear debris on performance. This research explores particle separation and characterization techniques to obtain information about the C-C wear process. The principle technique for particle separation is density gradient ultra-centrifugation (DGU) in which fibrous and matrix-rich particles are separated based on their density. Orthogonal analysis with Raman and UV-vis spectroscopy, optical and electron microscopy, and X-ray Photoelectron spectroscopy can then be made on separated aliquots. Understanding the properties of the wear particles and friction film gives information about the wear process and can help inform future design and material considerations.

Keywords

Carbon-Carbon Composite Wear Debris Characterization WP3.06 Dry sliding wear behavior of Fe-Cr-C-B hardfacing alloy modified with nano-CeO2

Junfeng Gou1, You Wang2, Chaohui Wang3, Yongkang Zhang1, Guan Wang1 1Guangdong University of Technology, China. 2Harbin Institute of Technology, China. 3Qiqihar university, China

Abstract

In this paper, the effect of nano-CeO2 on the wear behavior of Fe-Cr-C-B high chromium cast iron hardfacing alloy was studied under different wear loads. A ball-on-disc tribometer was used to perform the friction and wear tests sliding against WC-Co cemented carbide ball. The results showed that nano-CeO2 and wear load had obvious effects on coefficient of friction and wear resistance of the hardfacing alloy. Both of the coefficients of friction and wear rates of the hardfacing alloys decreased firstly and then increased with the increase of nano-CeO2. The wear rates of the hardfacing alloy with 0.288wt.% nano-CeO2 under wear loads of 20N and 30N decreased by 49% and 46% compared to those of the hardfacing alloy without modifier, respectively. The wear mechanisms of the hardfacing alloys included abrasion wear, adhesion wear and oxidation wear. The main wear mechanism changed from abrasion wear to adhesion wear when normal load increased from 10N to 20N and 30N. Nano-CeO2 could improve the microstructure of the hardfacing alloy, the main modification mechanisms of which are refining primary M7C3 carbide and purifying grain boundary. Overall work function of the hardfacing alloy could reflect its wear resistance to some extent.

Keywords hardfacing alloy nano-CeO2 wear mechanism work function WP3.07 Study of boriding surface treatment on the tribological behavior of AISI 316L stainless steel

L.A. Arteaga-Hernandez1, C.A. Cuao-Moreu1, C.E. Gonzalez-Rivera2, M. Alvarez-Vera3, J.A. Ortega-Saenz4, M.A.L. Hernandez-Rodriguez1 1FIME/CIDET, Universidad Autonoma de Nuevo Leon, Mexico. 2Universidad Autonoma de Nuevo Leon, Mexico. 3COMIMSA, Mexico. 4The University of Texas Rio, USA

Abstract

AISI 316L stainless steel possesses high tensile and rupture strength at low and high temperatures, therefore it is employed in several industry fields like manufacturing gas turbine parts, automotive pieces, and also prosthetic devices like joint prosthesis. However, the debris and oxides products resulting from wear, lead a detrimental performance limiting some applications with high tribological requirements. On the other hand, researches in the last few years have been focused to improve the tribological performance of the steel surface, including ceramic coatings and different engineering surface treatments. The present study assessed the tribological performance of borided layers synthesized on an AISI 316L. For this purpose, diffusional boriding treatments were performed at the following parameters: 850, 950, and 1050°C during 2, 4, and 6 h for each temperature. Surfaces were characterized using scanning electron microscopy, X-ray diffraction, micro-hardness testing, and roughness measurements. The tribological response was studied by means of ball on disc tribometer under dry-sliding conditions with a distance of 10 Km where were tracked their friction coefficient, mass loss, wear rate, and surface damage. All borided conditions decreased the wear rate in comparison with the untreated samples. The differences on wear performance among the borided surfaces were detailed discussed on this paper.

Keywords

Tribology Boriding Coatings AISI 316L steel WP3.08 Wear of cemented carbide forging dies used in zipper production

Jannica Heinrichs1, Hiroko Mikado2, Urban Wiklund1, Shingo Kawamura2, Staffan Jacobson1 1Uppsala University, Sweden. 2YKK Corporation, Japan

Abstract

Zipper production includes complicated cutting and forging processes to arrive at the final zipper element shape. The forging process involves significant plastic deformation of the work piece, and many millions of repeated contacts, each with a short sliding distance, between the tool and the work material. Cemented carbide tools, consisting of hard WC particles in a ductile Co binder, are commonly used in these processes, to have durable tools with acceptable wear. Although the zippers are made in a relatively soft CuZn alloy, tool life is a limiting factor in production. Hence, reducing the wear rate or delaying the critical wear would be very valuable for the industry. Not only would the downtime, materials consumption and costs decrease, but also the product quality would benefit. Investigations of the initiation and propagation of wear increase the understanding of the wear process, which ideally lead to improved tools with prolonged life. The initiation and progress of the wear of forging dies has been studied on a series of tools used for forging from 1000 up to 25 million zipper elements. The tools surfaces were studied in detail using high resolution imaging, complemented by elemental analysis and wear measurements. The Co binder is preferentially worn during use and transfer of CuZn alloy to the formed cavities occurs already from the start. Interestingly, the repeating forging contacts lead to modification of the composition of the transferred material, which partly separates into Cu and Zn rich parts, where the Zn rich parts show a high presence of oxygen. The WC grains are gradually worn, however not in level. Instead, they become faceted. The most severely worn area of the forging dies develops an increasing surface roughness, which becomes replicated on the corresponding zipper element area.

Keywords

Cemented carbide Tool wear Forging CuZn alloy WP3.09 Investigation of the impact wear behavior of 2.25Cr-1Mo tubes under elevated temperature

Xudong Chen1, Liwen Wang2, Lingyun Yang1, Rui Tang1, zhenbing Cai1 1Southwest Jiaotong University, China. 2Dongfang Electric Corporation, China

Abstract

The impact wear test of heat transfer tube material (2.25Cr-1Mo steel) against with the tube support plate material (Gr5C12 alloy) were performed at a controlled kinetic energy impact wear rig. The effect of temperatures (25℃, 225℃, 450℃) on the impact wear damage mechanism was investigated. The contact force, energy absorption, and interface deformation during the impact process were real-time collected and analysed. Wear volume, morphology, and the elemental distribution of the wear scar are used to characterize the wear and tribo-chemistry behaviour. Results showed that dynamic response of 2.25Cr-1Mo steel is clearly different at varied temperature. The wear volume increased first and then decreased with the increase in temperature and 2.25Cr-1Mo steel absorbs less energy and presents large deformation at higher temperature. Because the higher temperature causes the surface hardness of the material to decrease. Abrasive wear and oxidative wear occurs at the wear scar under different temperature, but a higher temperature case the more serious oxidative wear.

Keywords

Heat transfer tube 2.25Cr-1Mo Impact wear Elevated temperature WP3.10 Effects of engine oil chemistry and soot on piston-liner wear

Ping Lu, Hin Fung Lai, Jo Grundy, Terry Harvey, Zaihao Tian, Robert Wood University of Southampton, UK

Abstract

Modern internal combustion engines (ICEs) often feature the use of a stop-start engine function, either by itself or when integrated into a hybrid setup. This effectively increases the number of start cycles where the lubricant film has not been fully established, and more wear could be induced compared to the uninterrupted process. This work explores the effect of additives, soot, and oxidation on wear and friction in stop–start testing. Tests were conducted with ASTM A48 Class 40 Gray Cast Iron plates against AISI 52100 Chrome Steel Rollers. The plates used in the current work were first cut flat by machine and subsequently grounded by sanders with a 35° cross-hatching pattern, which simulates the true texture of the internal wall of the engine cylinder. The anti-wear effects were evaluated by testing base oils and fully formulated oils with ZDDP. The presence of soot in engine oil is above an important factor which is known to affect the lifespan of the mechanical components in an internal combustion engine, all of which experience frictional forces during operation. In this study, both soot contaminated and uncontaminated blends of above engine oils were tested. Wear rates, wear mechanisms and friction will be discussed and trends in wear will be explained using surface topography and contact potential (film thickness) and vibration. Significant improvements in anti-wear characteristics were observed in both sooted and uncontaminated environments, and wear analysis showed that these improvements are largely attributed to the presence of ZDDP. Moreover, results were also analyzed using advanced statistical modelling to determine the relationship between friction and vibration. Advanced statistics modelling results suggest the presence of soot had an effect that increased the vibration through friction or vice versa.

Keywords piston-liner soot ZDDP WP3.11 Microstructure and erosion wear properties of high chromium cast iron added nitrogen by high pressure in alkaline sand slurry

Liujie Xu, Fangfang Wang, Fugang Lu, Yucheng Zhou, Shizhong Wei Henan University of Science and Technology, China

Abstract

Erosion wear is widespread and serious in slurry transport field. To enhance erosion wear properties of high chromium cast iron (HCCI), a new high chromium cast iron with 0.38% nitrogen (HCCI-N) was fabricated by vacuum induction positive pressure melting furnace under nitrogen partial pressure of 0.4 MPa based on the established (xFe-27Cr-2.2C)-N pseudo-binary phase diagram. The microstructure and erosion wear behavior of HCCI-N were researched in alkaline sand slurry. Results show that the microstructure of HCCI-N is characterized by multi-scale carbides, including eutectic M7C3 (~20μm), secondary M23C6 (~3μm) and Cr2(C, N) (~600nm), distributed in matrix composed of martensite and austenite. A sandwich structure of M7C3-ferrite-martensite was formed at the boundary of eutectic M7C3. The nitrogen element is mainly distributed in matrix, and some nitrogen precipitate out from matrix to forms fine Cr2(C, N). The Cr2(C, N) (-1011) is coherent with Martensite (110). The erosion wear is caused by the synergistic effect of corrosion and wear. The pure wear rate (Ve) of HCCI-N accounts for 71%~93% of total erosion-wear rate (Vt) under different test condition, indicating that wear loss mainly results from mechanical action under alkaline sand slurry. Nevertheless, the synergism rate of corrosion and wear (Vs) is also significant to Vt, which accounts for 7%-29% of Vt for HCCI-N relative to 13%-31% of HCCI. The HCCI-N has more excellent erosion wear resistance compared with that of HCCI under all the test condition, and the optimal wear resistance of HCCI-N is 1.34 times that of HCCI. The nitrogen element dissolved in matrix increases corrosion resistance and decreases synergism rate of corrosion and wear. The multi-scale carbides strengthen matrix and resist mechanical wear action. The combined action of the two factors makes the HCCI-N have excellent resistance.

Keywords high nitrogen high chromium cast iron multi-scale carbides erosion wear WP3.12 The erosion-corrosion of a sewage steel pipe

Christian Paglia, Cristina Mosca Institute of materials and constructions Supsi, Switzerland

Abstract

Sewage steel pipes are used in special cases for the transportation of aggressive liquids in defined treatment plants areas. These are sometimes located some kilometers away from the original collecting places of the material. Degradation takes place within these materials, through a combination of electrochemistry, chemistry and erosion-corrosion issues. The corrosion of a low carbon steel pipe with a diameter of 800 mm was investigated. The 45 years old pipe with a wall thickness of 6.3 mm was placed in a 3 km long concrete tunnel. The steel junction were performed with helicoidal weldments. The coating consisted of a bi-component epoxy resin and a three-layers bituminous solvent applied on site, with a total thickness of 500 μm. A partial restoration was carried out after 25 years. The external protection was done by using a Polyethylene-based coating with a total thickness of 3.2 mm. Localized corrosion was caused by the chemical aggressive environment. A large erosion-corrosion component was also detected in the lower parts and promoted the perforation. Especially, in the presence of the liquid flux along the central axis, 15-20 mm after the helicoidal weldments. In these zones, turbolences emphasized the phenomena. The thickness of the original and the restoration epoxy coatings were significantly reduced compared to the required values. Generally, the thickness variation of the original protection layers made local restoration more difficult. Consequently, the efficacy and the long-term resistance was reduced. The hypothesis of a complete restoration and rotation of the pipe may extend the durability of the system. In this concern, it was necessary to verify the residual steel wall coating thickness as well as the thickness of the steel wall portion from a mechanical point of view. Nonetheless, localized corrosion was also observed in the middle and upper pipe sections.

Keywords sewage pipe erosion corrosion WP3.13 Strain on first bodies induced by rheology of third body

Olivier Bouillanne1,2, Guilhem Mollon1, Aurélien Saulot1, Sylvie Descartes1, Nathalie Serres2, Guillaume Chassaing2, Karim Demmou2 1LaMCoS, France. 2Safran Aircraft Engines, France

Abstract

In aircraft turbofans, blades are attached to the central disk with a dovetail joint. Because of aerodynamic instabilities, fretting occurs in the contact, which can lead to wear and cracking in contacts. The relative motion between blade and disk creates particles of third-body. Particles flow accommodates velocities and transmits load in this dry sliding interface [1].

A software developed at LaMCoS called MELODY uses a multibody meshfree approach to model third body between two first bodies. Particles of third body are highly deformable, and allow modelling various regimes of flowing: laminar, turbulent, pasty, agglomerated, etc. [2]. Three main parameters were identified: E, a normalized stiffness; c, a normalized cohesion and α, a normalized viscosity.

The purpose of these simulations is to apply realistic loading conditions, and to investigate the consequences of third body rheology on the tribological loading endured by first bodies. A pressure similar to that existing in blades/disk contact is applied on the top first body. After a compaction phase, a tangential velocity is imposed on the upper first body and shears the third body. By choosing parameters of rigidity and cohesion, we model four different flow regimes which make sense from an experimental viewpoint. The lower first body is also deformable; impact of flow regimes on the stress fields in space and time is then visible (Fig. 1). Fig. 1: Simulation with 1000 deformable grains submitted to compression and shear, with a deformable lower first body. Color indicates von Mises stress.

References: [1] Y. Berthier, L. Vincent, M. Godet, Velocity accommodation in fretting. Wear, Vol. 125, Issue 1 – 2, pp. 25 – 38, 1988. [2] G. Mollon, Solid flow regimes within dry sliding contacts. Tribology Letters, Vol. 67, Issue 4, p. 120, 2019.

Keywords

Third body Simulation Fretting Wear WP3.14 Effects of sediment size and type on the tribological properties of NBR in water chaozhen yang, xincong zhou, jian huang, fuming kuang, xueshen liu Wuhan University of Technology, China

Abstract

Nitrile Butadiene Rubber (NBR) is widely used in ship water-lubricated stern tube bearings. During the actual navigation of the ship, the presence of sediment will seriously affect the friction and wear performance of the water-lubricated rubber stern bearing. In this study, the effect of sediment on the friction performance of water lubricated rubber bearings was studied by changing the particle size and type of sand. This includes two types of sediment, (1) Standard SiO2 particles with particle sizes of 25, 48, 75 and 150um, (2) Sediment particles with particle sizes of 48-60, 75-90 and 120-150um from the Yangtze River. The friction coefficient, wear volumes and surface morphology were measured and it was found that the wear of NBR by SiO2 particles is worse than sediment in a certain range of particle size. But different types of sediment didn’t affect the friction coefficient. The particle size had significant effects on the tribological properties of the friction pairs. The friction coefficient became larger firstly and then smaller as the particle size increased, among which the friction coefficient and wear volume of NBR are the largest when SiO2 particles size is 48um. The friction coefficient decreases with the increase of velocity and applied load, regardless of the type of sediment and particle size. The above can provide an important reference for the design of practical Marine water-lubricated bearing material.

Keywords

Nitrile butadiene rubber Particle size Sediment Friction and wear WP3.15 Comparison of dry sliding tribological behavior of SS 316L impregnated with MoS2 vs h-BN solid lubricants: A statistical point of view

Surapol Raadnui1, Sitthipong Mahathanabordee1, Ruangdaj Tongsri2, Monnapas Morakotjinda2, Pongsak Wila2 1King Mongkut's University of Technology North Bangkok, Thailand. 2National Metal and Materials Technology Center, Thailand

Abstract

The main aim of this paper is to statistically discuss the friction and wear behavior of SS 316L impregnated with MoS2 and h-BN solid lubricant under different test conditions at room temperature, namely, sliding speed, applied load, sliding distance, solid lubricant mixing percentage and then to analyze the effect of wear variables on the friction coefficient and wear, which can be effectively helpful for the evaluation of solid lubricant mixing percentages on friction and wear characteristics. To investigate the influence of specific independent variables on dry sliding wear of stainless steel grade 316L (AISI SS 316L) impregnated with different percentages of MoS2 and h-BN solid lubricant, factorial experimental design is employed. The paper objective is to optimize the dry sliding pin on disc wear test results statistically and physically analyses of quantitative wear such as specimen weight loss, friction coefficient, rising of specimen temperature and qualitative analyses of both worn surface analysis and wear particle morphology by observation of optical and SEM micrographs. The utilization of the statistical design of experiment enable us to collect and analyses wear data indicating the extent to which the more understanding of the complex mode/mechanism of sliding wear of SS316L metal composite is anticipated. In addition, tribological responses from the tested results are further explored by Response Surface Methodology (RSM).

Keywords

Factorial design of experiment Metal composite Response surface methodology Solid lubricant WP3.16 In situ tribometry and tribofilm analysis of Astaloy 85Mo matrix composites

Michell Ordoñez1, Maria Cristina Farias2, Sylvie Descartes3, Izabel Machado1, Roberto Souza4 1Escola Politécnica da Universidade de São Paulo, Brazil. 2Universidade de Caxias do Sul, Brazil. 3Université de Lyon, INSA-Lyon, France. 4Surface Phenomena Laboratory, Escola Politécnica da Universidade de São Paulo, Brazil

Abstract

Under dry sliding conditions, reinforcements with different functionalities, such as hard carbides and solid lubricants, modify the nature and flow of third body, which make difficult the interpretation of the tribological behavior of metal matrix composites (MMC). This work presents an in situ tribometry study on the friction and wear behavior of composites with Astaloy 85Mo steel matrix, fabricated by spark plasma sintering (SPS), with the addition of different reinforcements: WC, graphite, and MoS2. The tribological evaluation was conducted using a home built tribometer that allowed the contact of sintered composite hemispheres against two different counterface materials: a steel disc for ex situ analyses and a transparent sapphire disc that enabled in situ optical observation of the third body flows. To understand the coefficient of friction changes during the sliding tests, simultaneous signals of the frictional force and the spatial pin displacement were recorded. Tests were conducted in dry conditions, at a nominal contact pressure of 1.2 GPa and with a sliding speed of 0.02 m.s-1. For sliding contacts involving WC-containing MMC, hard abrasive transferred particles promoted high friction coefficient values (0.63) and abrasive wear of the counterbody. In contrast, for the graphite-containing MMC, the third body developed during the first stage of contact evolved from a fine carbon powder to a transferred tribofilm that significantly reduced and stabilized the friction coefficient to values near 0.3. The different particle additions have significantly reduced the wear coefficient, in comparison with the unreinforced Astaloy 85Mo steel.

Keywords

Sintered Composites In-situ tribometry Carbides Solid lubricants WP3.17 Braking backward history dependency analysis of pad-disc contact

D. Tumbajoy-Spinel1, A.-L. Cristol2, Y. Berthier1, S. Descartes1, Y. Desplanques2 1Univ Lyon, INSA-Lyon, CNRS, France. 2Univ Lille, CNRS, France

Abstract

Research objective This work aims at the understanding of the behaviour of friction materials in braking situations depending on the usage, especially the thermal backward histories. It deals with sintered metal matrix linings used with steel brake discs. Methodology Specific braking test sequences are developed in order to produce fairly recurrent mechanical states and to compare two different thermal backward histories for the same disc-pad contact. Two sequences are carried out using slowdown braking tests, (i) without and (ii) with cumulative heat. At the end of sequences, a series of low-energy slowdowns ended by a hold-braking test is done to restore the pad surface for both case scenarios. The surface tribological evolutions are correlated with the thermo-mechanical measurements. A comparison between both cases is carried out as well, focussing on pad and disc material changes and characteristics of the third-body layer. Results A cartography of temperature surface evolution has been obtained. The surface of the pad evolves differently according to the local temperature level at each region. Homogeneous third body plateaus appear in zones of higher temperatures (higher power dissipation) for the last mechanical phase. At a local scale, third body morphologies have been analysed through scanning electron and ion microscopies coupled with EDX. In the case of “cumulative heat” sequence third body is compacted and fully mixed, while it is powdery in the case of “without cumulative heat” sequence. Conclusion The results highlight 3 characteristic scales closely linked. The approach would allow to identify thermomechanical processes involved within the disk/pad contact. Taking into account the tribological triplet, in particular the interfacial layer (third body), would contribute to a better understanding of brake behaviour. Acknowledgments The authors acknowledge the Research French Agency (project ANR- 12-VPTT-0006) for the financial support. They thank Flertex Sinter (Gennevilliers, France) for providing the specimens.

Keywords braking metallic composite materials third body WP3.18 The role of the counterbody material on tribological properties of 316L+WC composite coatings processed by laser cladding

Enrico Saggionetto, Tommaso Maurizi Enrici, Olivier Dedry, Daniele Mario, Iñigo Serrano Martín, Jérôme Tchoufang Tchuindjang, Anne Mertens University of Liège, Belgium

Abstract

This work considers a metal matrix composite composed of 316L stainless steel and reinforcements of tungsten carbides (WC) particles (20 in vol.%), fabricated by laser cladding with a complex hierarchical microstructure (Figure) [T. Maurizi Enrici et al., Adv. Eng. Mater. (2020)]. Pin-on-disk tests were performed in order to determine the influence of the reinforcements on its wear behaviour. Particular attention was given to the counterbody, since the ball material has an important role in the wear behaviour. For this purpose, alumina and WC balls were chosen due to their high hardness.

By using alumina, a complex wear sequence was evaluated by looking at the variation of the friction coefficient (µ) and the penetration depth (PDe). The sequence involves different wear mechanisms. The use of alumina allows to determine easily the nature of the debris formed during the test since Al is not present in the composition of the composite. Nevertheless, this hard debris can lead to significant wear of the ball and a not realistic evaluation of the wear performance. In contrast, the use of WC ball allows to obtain a good estimation of the wear resistance since the wear of the ball is negligible. Nevertheless, the use of WC ball leads to more difficulties in the interpretation of the wear mechanisms, since W is present in both counterbody and composite.

For both counterbodies, the novel approach of the interrupted test was applied, where wear tests are performed under the same conditions and strategically stopped at times corresponding to specific variations of μ and PDe. Post-mortem observations of the wear track and the counterbodies were carried out by means of Scanning Electron Microscopy (SEM) and profilometer measurements.

Keywords

Laser Cladding Stainless Steel Metal Matrix Composites Tribological Properties WP3.19 Erosion evaluation of elbows in series with different configurations

Thiana Sedrez, Siamack Shirazi University of Tulsa, USA

Abstract

Erosion of elbows in series has received more attention recently as many facilities have elbows in series with various orientations and installations. It has been observed from experiments that, for liquid-dominated flows when the elbows are placed in series and with a small distance between them, the maximum erosion takes place in the second elbow. However, it is also necessary to study the effect of the orientation of the elbows because in the oil and gas industry, for example, there are all types of combinations of elbows in series in the field. In this work, experiments were conducted in a 50.8 mm diameter experimental facility considering two configurations of elbows in series: the Π-type, where the first elbow for both configurations is upward vertical- horizontal and the second elbow orientation is horizontal-vertical downward, and the Z-type, where the second elbow orientation is horizontal-vertical upward. Also, the distance between elbows was kept constant (being three diameters). Additionally, Computational Fluid Dynamics (CFD) studies are performed and compared with experiments. After validation and sensitivity studies concerning numerical solutions, a comprehensive numerical study was conducted, taking into account different scenarios regarding the orientation of elbows using three configurations of elbows in series. The results show that the location of maximum erosion for the second elbow does not change for different orientations of elbows. On the other hand, for the first elbow, the location of maximum erosion tends to be at the inner wall of the elbow for some orientations. The Π-type configuration of elbows in series is not as sensitive to the orientation of the elbows as the other two configurations investigated. Thus, it is important to understand the erosion behavior with the orientation of the elbows, because erosion can be reduced by changing the orientation or the configuration of elbows in series.

Keywords erosion elbows in series multiphase flows gravity effect WP3.20 Dynamic simulation of CFRP strengthened RC members under unequal trans-lateral impact loading

Khalil Al-Bukhaiti, Zhao Shichun, Liu Yanhui Southwest Jiaotong University, China

Abstract

Carbon fiber reinforced polymer (CFRP) strengthening of Concrete structures under impact loading has shown great potential in recent years. However, Concrete structures are often experienced natural (e.g., earthquake, wind) and human-made (e.g., vehicular impact, blast) dynamic loading. Therefore, there is a growing interest among the researchers to investigate the capability of CFRP strengthened elements under such dynamic conditions. This study focuses on the experimental test. The finite element (FE) numerical modeling and simulation of CFRP strengthened RC elements under unequal trans-lateral impact loading to predict the behavior and failure modes. The impact simulation process and the CFRP strengthened RC elements are validated with the existing experimental results in this study. The validated FE model of CFRP strengthened RC element is then further used to investigate the effects of unequal trans-lateral impact loading on its structural performance. The results are presented in terms of unequal trans-lateral impact force, lateral deflection, and deformed shape to evaluate the CFRP strengthening technique's effectiveness. The effects on the impact resistance of the elements were analyzed as the parameters for this study. Comparisons between unstrengthen RC element and strengthened CFRP-RC element clearly indicate the performance enhancement of strengthened element under unequal trans-lateral impact loading.

Keywords

CFRP-RC component failure mode wrapping method lateral deflection WP3.21 A novel contact model for rough surfaces using piecewise linear interpolation and its application in gear wear

Hongbing Wang1, Changjiang Zhou1, Haihang Wang1, Bo Hu1, Zhongming Liu2 1Hunan University, China. 2Zhengzhou Research Institute of Mechanical Engineering Co., Ltd., China

Abstract

Wear is directly related to rough surface contact, and the accuracy of a wear prediction model depends on the accurate determination of contact pressure. In this work, a numerical model with high computational accuracy for rough surface contact is developed and applied to the wear prediction of spur gears. To acquire contact pressure, the integral equation that contact pressure should satisfy is discretized into a set of linear equations by piecewise linear interpolating contact pressure. Then, a gear wear model including rough surface contact is established. The proposed contact model is verified by comparing with smooth and rough surface contact, and the wear depths of a spur gear drive with geometry and pressure updates are analyzed. Result shows that a small roughness value among contact surfaces may cause a large change in contact pressure. The effects of main design parameters on gear wear are subsequently investigated. Gear wear is found to decrease with increased module and pressure angle but increases with increased transmission ratio and input torque. These findings indicate that reasonable parameter matching is beneficial to improving gear wear resistance.

Text Abstract

Wear is directly related to rough surface contact, and the accuracy of a wear prediction model depends on the accurate determination of contact pressure. In this work, a numerical model with high computational accuracy for rough surface contact is developed and applied to the wear prediction of spur gears. To acquire contact pressure, the integral equation that contact pressure should satisfy is discretized into a set of linear equations by piecewise linear interpolating contact pressure. Then, a gear wear model including rough surface contact is established. The proposed contact model is verified by comparing with smooth and rough surface contact, and the wear depths of a spur gear drive with geometry and pressure updates are analyzed. Result shows that a small roughness value among contact surfaces may cause a large change in contact pressure. The effects of main design parameters on gear wear are subsequently investigated. Gear wear is found to decrease with increased module and pressure angle but increases with increased transmission ratio and input torque. These findings indicate that reasonable parameter matching is beneficial to improving gear wear resistance.

Keywords rough surface contact pressure wear depth gear drive WP3.22 Scratch and corrosion behaviour of PTFE-ceria composite coating

Harprabhjot Singh1, Supreet Singh2, Jatinder Pal Singh3, Harpreet Singh1 1Indian Institute of Technology Ropar, India. 2Chandigarh University, India. 3Lovely Professional University, India

Abstract

Hydrophobic materials being water repellent are proved to be corrosion resistant. In present work polytetrafluoroethylene (PTFE)- 20 wt% ceria composite is developed with aim to get scratch resistant hydrophobic material. Scratch test is performed on sintered PTFE and PTFE- 20 wt% ceria composite. Composite showed better scratch resistance with nearly unaltered hydrophobic properties. Composite is adhered to plasma sprayed Ni3Al coating using press sintering technique. Scratch test revealed good adhesion between composite coating and substrate. Further, potentiodynamic corrosion test was carried on substrate (plasma sprayed Ni3Al coating) and composite coated surface. Significant improvement in corrosion resistance is measured.

Keywords

Scratch test Corrosion Hydrophobic coating polymer composie WP3.23 Mechanical, sliding wear and corrosive behavior of Al composites containing varying beryllium aluminum silicate and constant CeO2

Vikas Verma1, Ronaldo Camara Cozza2, Vladimir Cheverikin1, Alexander Kondratiev1, Ramkumar Penchaliah3 1National University of Science and Technology (NUST) MISiS, Russia. 2University Center of FEI, Brazil. 3Indian Institute of Technology (IIT) Madras, India

Abstract

Effect of addition of varying beryllium aluminum silicate (Be3Al2(SiO3)6) and constant cerium oxide content as reinforcements on mechanical, wear and corrosive behavior of aluminium metal matrix composites prepared via stir casting route was investigated. Hardness and ultimate tensile strength increased with 36% and 43% respectively with 9%beryl addition. Further, effect of constant 0.5 weight % CeO2 in Al beryl composite was evaluated and was found that CeO2 additions has not affected the mechanical or wear properties of the composites significantly but remarkably improved corrosion resistance. Tribological performance of the composites was investigated by conducting sliding wear tests against steel at different loads in dry and wet conditions. Coefficient of friction (COF) is found to be least for beryl-CeO2 added composites in wet sliding conditions. Characteristics features of adhesion, fracture and delamination were observed in micrograph of the worn composite having low beryl content slid in air whereas abrasive wear predominates in water or oil. Addition of increased weight% of beryl particles led in reduced wear at all loads. Increase in corrosion resistance by 45% decrease in weight loss with 0.5% CeO2 addition was observed. Al6061-9%beryl- 0.5%CeO2 composite with high hardness, wear and corrosion resistance was found most promising for structural applications.

Keywords

Stir casting Sliding wear Corrosion Beryl WP3.24 Subsurface microstructural evolution in iron after scratch testing

Dominic Linsler1, Friederike Ruebeling2, Christian Greiner3 1Fraunhofer IWM µTC, Germany. 2Karlsruhe Institute of technology IAM, Germany. 3Karlsruhe Institute of Technology IAM, Germany

Abstract

Subsurface microstructural evolution due to tribological contact loading is of interest for the understanding of friction and wear phenomena. Due to the manifold factors that influence friction and wear of tribological contacts, one approach is to start with an unlubricated model system that consists of an electropolished disk and a mechanically and chemically inert pin. Previous research has shown the evolution of a dislocation trace line in a few hundred nanometers depth below the worn surface in OFHC Cu. Those materials are all fcc and it is of basic interest, if the findings can be transferred to a bcc material. In the present study, we did scratch tests with a ruby ball on electropolished iron to investigate the subsurface microstructural evolution in different wear track depth. Analysis of the subsurface microstructure with T-SEM showed a dislocation trace line only after the onset of ploughing, but it is excluded that the dislocation trace line occurs due to a folding mechanism. The results reveal similar features of the subsurface microstructure after one pass in iron and copper and give new insights in the microstructure evolution during tribological loading.

Keywords subsurface microstrutural evolution dislocation trace line scratch testing folding WP3.25 Wear mechanisms in ultrafine-grained copper processed by severe plastic deformation

Evander Ramos1, Takahiro Masuda2, Yoichi Takizawa3, Zenji Horita4, Suveen Mathaudhu1 1UC Riverside, USA. 2Yokohama National University, Japan. 3Nagano Forging Co., Japan. 4Kyushu University, Japan

Abstract

The wear properties of ultrafine-grained materials produced by different severe plastic deformation processes has been an area of active study. Although the grain refinement offered by these processes increases hardness and strength, not all reports have seen an increase in wear resistance as might be expected. In this work, reciprocating sliding wear tests were conducted on pure copper processed by high pressure torsion and high pressure sliding. These wear tests were conducted in judicious locations with regards to the imposed processing directions and strains to compare with other works in the literature. The results indicate that the wear response can be influenced by microstructural variation beneath sliding wear tests due to texture or grain morphology. These findings suggest that the influence of track location and direction on ultrafine-grained materials should be considered when comparing reported wear data across literature reports.

Keywords

Ultrafine-grained (UFG) Copper Severe plastic deformation (SPD) WP3.26 Tribological mechanism of surface texture in transition stage from failure of starved lubrication to dry friction

Xianjuan Pang, Yixu Niu, Shiwei Yue, Bao Shangguan, Yongzhen Zhang Henan University of Science and Technology, China

Abstract

Service process of friction pair during lubrication includes initial stage of oil lubricationstable stage of oil lubricationstarved lubrication, dry friction and then finally complete failure. The friction coefficient of transition stage from failure of starved lubrication to dry friction is far lower than that of dry friction, which is not only the last line of defense for safe running of the friction pairs, but also possibly a new key point to prolong the extreme service life of the friction pair. The study showed that surface texture can effectively prolong the running time in the transition stage of starved lubrication-dry friction. In view of this, in this paper, the effects of surface texture on the tribological performances with PAO lubricant of transition stage are researched. Dynamic evolution of the friction film components in the transition stage is analysized. Micro-mechanism of antifriction and anti-wear of transition stage is revealed, which could reduce the friction coefficient and its fluctuation in the transition stage and extend the transition time, and then effectively prolong the extreme service life of friction pair. Finally, the surface texture control technique of extreme service life is proposed. The research results would not only further perfect the theory of starved lubrication and dry friction, but also provide data and theoretical support for prolonging extreme service life.

Keywords

Surface texture Tribological mechanism Starved lubrication WP3.27 Tribocorrosion in ferritic stainless steels: A methodological approach

Demian Abreu, Washington Silva Jr, Miguel Ardila, Jose Daniel de Mello Universidade Federal de Uberlandia, Brazil

Abstract

The goal of this study was to develop a potentiodynamics-based methodological approach for characterising the tribocorrosion of ferritic stainless steel. Synergistic effects in tribocorrosion systems have been widely investigated and debated under potentiostatic conditions. Because potentiostatic tests can ignore essential phenomena that are typically noticeable in potentiodynamic tests (potential scanning), a specific potentiodynamic-technique-based methodology was developed to analyse tribocorrosion synergy in ferritic stainless steels. The proposed methodology consists of performing sliding tribological tests to evaluate mechanical wear accurately, potentiodynamic corrosion tests to determine corrosion resistance in the absence of mechanical wear, and tribocorrosion tests to associate mechanical wear and corrosion degradation caused by chemical/electrochemical effects. Validation of the developed methodology consisted of its application to an 11% Cr ferritic stainless steel. The results demonstrate that tribocorrosion intensifies wear rates, but only by a very small amount. WP3.28 Understanding abrasion-corrosion / improving the concrete mixer drum performance: Laboratory and field approach

Wilian Labiapari1, Ricardo Gonçalves1, Claudio Alcântara1, Vitor Pagani1, Julio di Cunto1, José Daniel de Mello2 1Aperam Solth America, Brazil. 2Universidade Federal de Uberlândia, Brazil

Abstract

Two of Brazil's the most important economic activities are mining and agribusiness, representing, in 2017, 17.3 % of Brazilian GDP. It is crucial to note that water is vital for these sectors being the principal corrosive agent for carbon steel in these prominent sectors. The problems concerning wear resistance are closely linked to performance and, obviously, to economic issues. In this way, they are using increasingly efficient materials, which are wear-resistant, but, in most cases, they neglected corrosion resistance and, mainly, the combined effect of wear and corrosion, which accelerates equipment failure. In this paper, a specific focus on the sector that benefits minerals, the concrete industry, laboratory and field tests were performed comparing common carbon steels type A36, Advanced High Strength Steels (AHSS), and ASTM 410 ferritic stainless steels. Initially, a piece of laboratory equipment, approaching real-life use, was built, adapting a manual concrete. In the field, samples were placed in a sand processing equipment and, inside a concrete mixer drum in a truck. In the laboratory, rubber wheel and fixed ball microabrasion tests were performed. Both industrial and laboratory samples were collected and extensively analyzed using SEM, 3D surface topography, and hardness tests. Finally, a complete stainless steel concrete mixer drum was built, adapted to a truck, and field-tested for five years, since 2015. An increase in the equipment's useful life was observed in up to three times compared to the A36 carbon steel, standard in this application. The ferritic stainless steel in a watery concrete environment, even though it’s softer than AHSS, had better wear performance. In 2020, some companies started using ferritic stainless steel for the maintenance of concrete mixing drums. Also, manufacturers are using it as an alternative when longer service life, reduced downtime for repair, and weight reduction are required.

Keywords

Abrasion-corrosion Synergy Water Ferritic Stainless Steel WP3.29 Time dependent analysis of cavitation damage and the effect of cathodic protection

Morteza Abedini1, Stefanie Hanke2, Fabian Reuter3 1University of Kashan, Iran. 2University Duisburg-Essen, Germany. 3Otto-von-Guericke University Magdeburg, Germany

Abstract

We performed tests on cavitation erosion corrosion on CuZn39Pb3 brass samples submerged in a 3.5% NaCl aqueous solution exposed to acoustic cavitation. After various sonication times of up to 20 h, surface damage was characterized by scanning electron microscopy and the weight losses of the samples were measured. To separate the effects of erosion and corrosion and quantify the synergy between the two effects, tests were conducted with the sample being held at open circuit potential and with cathodic protection. Significant changes in the mass loss rate with testing time are observed and can be attributed to the successive changes in the variation of surface roughness and the surface morphology of the various phases present in the alloy. A positive cumulative synergism between erosion and corrosion is found for all testing times. However, data suggests that the role of corrosion on the erosion rate and, therefore, the synergistic effect of erosion and corrosion decreases with the sonication time.

Keywords cavitation erosion cavitation corrosion cathodic protection synergy WP3.30 Sliding wear behaviour of titanium alloy sheets produced by large strain extrusion machining

Pushpinder Kumar, Ravinder Singh Joshi, Rohit Kumar Singla Thapar Institute of Engineering & Technology, India

Abstract

Excellent resistance to corrosion and strength to weight ratio are the few of the intrinsic properties of titanium and its alloys that make them a strong choice of material in different applications of biomedical, aerospace, automotive and power plant industries. Titanium and its alloys are commonly used in wide varieties of shapes varying from rectangular to circular bars and sheets as input materials in these industries. For example Titanium sheets are utilized in Boeing 777 for making floor support, ducting system, brackets and clips etc. Rolling is a process commonly used for making thin sheets. Inducing large amount of strain in high strength materials with HCP structure such as Magnesium and Titanium alloys makes rolling a multistage process. Moreover, controlling crystallographic texture in multistage deformation processes is also very critical. To overcome these limitations of multistage deformation and uncontrollable microstructure, large strain extrusion machining process is used to produce bulk form in a single continuous operation with controllable microstructure. In present research attempt sliding wear behaviour of titanium alloy strips produced by large strain extrusion machining is analyzed using tribometer. Micro-hardness of fabricated strips is examined on Vickers Hardness tester and roughness tester is used for roughness measurement of the fabricated strips. X-Ray diffraction and scanning electron microscopy is used for metallurgical analysis of the strips and debris analysis of the worn samples. Hardness measurement revealed a ~ 40-65% increase in fabricated sheet in comparison to bulk material. This increase in hardness may be attributed to grain refinement resulted from high deformation induced by the process. The roughness values of the strips decreased with increase in strain rate. Wear study of the samples have shown better results for strips fabricated by the process in comparison to bulk material. Wear rate is lower in the direction perpendicular to grain elongation.

Keywords

Large Strain Extrusion Machining Shear deformation Ultrafine-grained materials Wear WP3.31 New multi-sensing nanotribology test with electrical contact resistance and friction measurement

Ben Beake1, Tomasz Liskiewicz2, Adrian Harris1, Sam McMaster3 1Micro Materials Ltd, UK. 2Manchester Metropolitan University, UK. 3University of Leeds, UK

Abstract

Nano-/micro-scale tribology enables the onset of wear to be studied in detail and correlations with friction forces investigated to aid the design of surfaces with improved wear resistance. Reciprocating contacts occur in a wide variety of practical wear situations including hip joints and electrical contacts. In optimising materials for improved durability in these contacts it is important that the contact conditions can be reproduced. A capability for rapid high-cycle linear reciprocating nano-scale wear tests has therefore been developed (NanoTriboTest) with automatic recording of friction loops, cumulative energy dissipation and electrical contact resistance. The design has high level of lateral rigidity providing the necessary stability to perform nano-wear tests for several hours, up to 35000 cycles and 300 m sliding distance. High cycle reciprocating nano-wear tests have been performed on multilayer DLC coatings, and biomedical alloys Ti6Al4V and 316L stainless steel. Stainless steel exhibited a ductile response throughout the load range but an abrupt transition to higher friction and fracture-dominated wear occurred on Ti6Al4V. Improved detection of the onset of wear and the subsequent failure mechanisms was achieved by a multi- sensing approach where changes to electrical contact resistance were shown to correlate with friction. Nano- wear tests of noble metal-noble metal contacts showed much longer endurance than gold vs. steel contacts although occasional isolated failures were observed in 35000 cycle tests.

Keywords electrical contact resistance nano-/micro- wear friction WP3.32 The effect of railway wheel wear on reprofiling and service life

Arthur Pires, Caroliny Endlich, Fábio Antoniolli, Isabela Dalvi, João Queiróz, Lucas Pacheco, Guilherme Santos Universidade Federal do Espírito Santo, Brazil

Abstract

The aim of this work is to develop a method for comparison between wheel profiles in terms of how service wear affects the reprofiling process. An optimization method was applied to develop three new candidate profiles to substitute the currently used profile in a Brazilian railway.. A computational wheel wear simulation was performed using a Multibody simulation (MBS) in order to quantify the service wear of the four profiles. The two inputs of the wear simulation are: the dimensional wear coefficient of the Archard model and the statistical representation of the railway, while the outputs are the worn profiles with its respective mileage. The worn profiles are then used to simulate the wheel reprofiling process, obtaining the number of possible maintenance interventions as the output. Finally the best candidate was chosen based on its service life and new wheel reprofiling intervals are proposed.

Keywords

Wear simulation Reprofiling Wheel life Wheel Maintenance WP3.33 Slurry-erosive wear and wear product analysis: Utilization of design of experiments for condition monitoring of slurry pump impeller

Surapol Raadnui King Mongkut's University of Technology North Bangkok, Thailand

Abstract

The slurry - erosive wear experiments were systematically and statistically carried out at different type of hard particles, slurry concentration, impeller rotational speed and test duration. To investigate the influence of specific independent variables on slurry - erosive wear of stainless steel grade 402 (AISI SS 402) impeller, factorial experimental design was employed. The paper aim to optimize the slurry - erosive pot wear test results statistically and physically analyses of quantitative wear such as specimen weight loss, pot bulk temperature, motor current consumption and qualitative analyses of both eroded worn surface analysis and erosive wear particle morphology by optical and SEM micrographs. Several issues have been addressed, these include main and interaction effect of independent wear variables, typical worn surface pattern analysis and wear debris morphological analysis. The utilization of the statistical design of experiment enable the author to collect and analyses wear data indicating the extent to which the more understanding of the complex mode/mechanism of slurry – erosive wear can be further explored. In addition, condition monitoring of impeller wear stages by utilization of wear particle analysis was anticipated.

Keywords

Factorial design of experiments Slurry erosion Wear particle analysis WP3.34 Micro-abrasive glass surface for producing microplastics for biological tests

Yoshitaka Nakanishi, Hajime Yamaguchi, Yusuke Hirata, Yuta Nakashima, Yukio Fujiwara Kumamoto University, Japan

Abstract

Plastic is the most prevalent type of marine debris found in oceans. Plastic debris exist in various shapes and sizes, but those less than 5 mm in length are called “microplastics.” A production system should be developed to investigate the influence of microplastics on the environment, animals, tissues, and cells in vitro. The purpose of this study is to develop a micro-abrasive surface for producing microplastics for biological tests. The production system was a pin-on-disc abrasive machine, where a pin made of high-density polyethylene (HDPE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), or polypropylene (PP) was pressed onto a quartz glass disc via an air cylinder. Relative motions between the pin and disc were applied using a table with actuators. The pin and disc were soaked in a saline solution, and ultraviolet irradiation was performed through the glass disc during the production. The combined application of a conventional photoresist masking process and microslurry-jet (MSJ) mechanical removal process was proposed for microstructuring the micro-abrasive glass surface. Masking patterns made of a photocurable resin (SU-8) were created on the glass, and both the SU-8 patterns and the exposed glass surface were simultaneously removed using the MSJ. When the sacrificial patterns were processed and removed by the MSJ, the glass surface with microstructures was created. It was confirmed that continuously curved convex structures up to 30 μm in diameter and 4 μm in height with highly transparent glass surfaces were created. The particles generated by the pin-on-disc abrasive machine were collected and cleaned with fresh ultrapure water and ethyl alcohol. Through the SEM analysis and the size distribution curves of the particles at each surface profile, it is evident that the quality management of microplastics is possible by adjusting the surface profiles on the quartz glass discs.

Keywords

Surface processing Glass surface Abrasive wear Microplastics WP3.36 A hybrid approach to analysis of tribological signals collected for surface-coated titanium alloy: Synergistic usage of chaos theory and scanning electron microscopy

Magdalena Łępicka, Grzegorz Górski, Małgorzata Grądzka-Dahlke, Romuald Mosdorf Bialystok University of Technology, Poland

Abstract

In the last years, a growing interest in analyzing various signals with the use of chaos theory is observed. Recently, chaos theory found its application also in tribology. For example, the nonlinear properties of tribosystems have been used e.g. to determine the machinability of steel based on its surface profiles, as well as to predict the reliability of bearing materials. In our work, we propose a hybrid approach to the analysis of tribological phenomena, based on the application of recurrence quantification analysis (RQA) and principal component analysis (PCA) on the registered signal of the coefficient of friction, in synergy with scanning electron microscopic (SEM) observations. In this study, a dry sliding test of a TiN- or DLC-coated Ti6Al4V alloy was conducted in a ball-on-disc configuration. As a counter-material, a WC-Co ball was selected. After tribological examinations, the selected aspects of COF signals were analyzed in Matlab with the use of the Cross Recurrence Plot Toolbox. This toolbox utilizes the recurrence quantification analysis (RQA) method, which finds its applications in the analysis of the phenomena that occur in dynamical systems. Moreover, SEM observations of the wear tracks were done to determine the prevalent wear modes of the surface-modified discs. According to the findings, the synergistic approach that utilizes both microscopic observations of the wear tracks, as well as tools for determination of nonlinear characteristics of the collected tribological signals, offers a valuable insight into the phenomena that take place during friction. With post-processing of the COF signals with PCA and RQA, it is possible to obtain information that is not available with the use of the conventional analysis methods. The successful application of both RQA and PCA will be presented on signals which were acquired during the actual wear tests of the surface-modified titanium alloy.

Keywords recurrence quantification analysis principal component analysis titanium nitride titanium alloys WP3.37 Synergy effect modelling of cavitation and hard particle erosion

Leonel Teran1, Santiago Laín2, Sara Rodríguez1 1Universidad del Valle, Colombia. 2Universidad Autónoma de Occidente, Colombia

Abstract

Cavitation damage and hard particle erosion are some of the main sources of wear in most of the hydraulic machines like pumps or hydro turbines. However, the synergic effect of these two phenomena leads to a wear phenomenon that is more severe than the sum of the individual effects of cavitation and hard particle erosion, and that has been scarcely studied. Therefore, in this work, simplified computational fluid dynamics (CFD) simulations are used to investigate the behavior of a particle interacting with a cavitation bubble under several conditions of pressure, position, size and mass of the particle. The results of this first approach lead to obtain a model that includes three non-dimensional variables: the dependent variable includes the particle velocity, while the other two include the particle position relative to the eroded wall and the particle mass. Then the particle velocity results are combined with a traditional hard particle erosion model, for AISI 304 steel, to obtain a new model capable of predict the synergic effect of the cavitation damage and hard particle erosion. This new model is implemented in a CFD software in order to compare the predicted erosion rate with experimental results obtained using a slurry pot erosion tester under two conditions of particle concentration and two conditions of particle size, combined with four triangular cavitation inducers that produced different cavitation conditions.

Keywords

Cavitation Hard particle erosion Computational fluid dynamics Synergy WP3.38 Slippage effect on crack behavior of the pearlitic steel induced by the rolling-sliding friction

Yan Zhou1, Zhenzhen Gui1, Teng Shen1, Jin-fang Peng2, Zhi-biao Xu3, Min-hao Zhu2 1Guangzhou University, China. 2Southwest Jiao-tong University, China. 3Wuyi University, China

Abstract

The slippage effect on crack behavior induced by rolling-sliding friction has been investigated, especially for the crack behavior with the pearlitie microstructure evolution. To controlling the slippage, the rolling contact friction tests were conducted on the twin disc tester allowed two disc samples with different velocities rolling against each other. Wear loss and cross-section of worn samples have been characterized by scanning electron microscope to show the crack behavior. The results were shown that the initiation of crack usually occurred at sub-surface sites of cross-section samples. and the plastic deformation induced by the rolling-sliding friction led the ductility exhaustion of the ferrite structure with some voids forming along the deformed line of ferrite in the pearlite structure, then several adjacent voids in the deformed ferrite phase connected resulted in the crack nucleation. In addition, the cementite dissolved behavior in the pearlite structure played an important role on the propagation direction of crack significantly, and the angle between the crack propagation direction and the worn surface was changed as the slippage increased. As the slippage increasing, the number of cracks were increased and observed with the dissolved cementite structure, which is gradually changed from the lamellar shape to fragment shape, and then into particles. The slippage effects on the competition of the crack fatigue and the wear loss of material during rolling-sliding friction. The length and depth of crack was used as a parameter to evaluate the crack damage. At a constant slippage, the crack propagation rate is faster than the material removed rate, the wear loss is lower while the crack damage is heavier, and the crack length get longer as the friction cycles increased. For a large slippage, the wear loss is higher and the crack damage is slow down, the crack length is shorter as the cycles increased.

Keywords crack induced by friction slippage rolling-sliding pearlitic steel WP3.39 Sliding and erosion wear behaviour of thermal sprayed WC-Cr3C2-Ni coatings

Digvijay Bhosale, Walmik Rathod Veermata Jijabai Technological Institute, India

Abstract

The present work investigates comprehensively tribological behaviour of WC-Cr3C2-Ni coatings prepared by atmospheric plasma spray (APS) and high-velocity oxy-fuel (HVOF) spray methods. The dry sliding wear at room and elevated temperature (up to 800°C), wet (oil-based fracturing fluid) sliding wear at room temperature were studied against the alumina ball using the ball-on-disc tribometer according to the ASTM G99 standard. The erosion wear was studied using air-jet erosion tester (ASTM G76) at the impact angles 30° and 90° and temperatures 500°C and 650°C. Although both coatings show higher hardness, dense morphological structure and a lower degree of decarburisation, the HVOF coating offers better wear resistance over the APS coating under both dry and wet sliding conditions. Significant improvement in the wear resistance, especially above 500°C is attributed to the uniform formation of thick lubricous WO3. The solid particle erosion resistance of both coatings is observed to be the same up to 650°C under 30° and 90° impact angles.

Keywords

Thermal spray coating Sliding wear Erosion wear Ceramic coating WP3.40 Investigation of the glaze layer stability under thermal cyclic fretting loadings

Alixe Dreano, Soha Baydoun, Siegfried Fouvry LTDS, Ecole Centrale de Lyon, France

Abstract

The wear behavior of metallic alloys at variable temperature is a crucial aspect in many industrial components such as the turbines in aircraft engines. The blade/disk contact is subjected to cyclic thermal loading combined with fretting which can significantly damage the interface (Fig. 1a). The studied contact is a cobalt-based alloy sample fretted against alumina in a cross-cylinders configuration at 600°C. At such temperature, a protective third body referred to as “glaze layer” is spontaneously created at the interface. This layer exhibits excellent tribological properties which lead to an unworn regime. Previous study demonstrated that the glaze layer is thermally activated by a tribo-sintering process of cobalt oxide wear debris. It was also suggested that the excellent tribological behavior of the glaze layer may be either explained by its ductility at high temperature or by a continuous tribo-sintering process, leading both to a drastic reduction of the ejected wear debris. A high-temperature wear model was then proposed to predict the wear variations for such system [1]. To be more representative of the blade/disk contact, it is now suggested to investigate the stability of the protective glaze layer for thermal and sliding cyclic tribological conditions. The objective is to investigate the behavior of the interface when soliciting outside the stability range of the glaze layer. Firstly, results show that the glaze layer is destroyed at low temperature within a latency time, emphasizing the importance of the diffusive properties of this layer. Experiments also highlight the importance of cyclic history in the formation/destruction process of the glaze layer (Fig 2b). Finally, it is proposed to model the wear variations for such cycling loading conditions. [1] Dreano et al., Wear, 2020. Fig. 1 : a) Representative blade/disk contact ; b) Evolution of the wear behaviour during cyclic temperature fretting-wear

Keywords

Fretting Glaze Layer High temperature Wear model WP3.41 Suppressing notch wear in the side milling of a Ti-6Al-4V alloy

Ricardo Inácio1, Rodrigo Lopes da Silva2, Amauri Hassui1 1University of Campinas, Brazil. 2Federal University of Technology - Paraná, Brazil

Abstract

Despite many advantages offered by titanium alloys in comparison to other conventional materials in the industry, several manufacturing challenges arise, and they are associated with titanium mechanical, thermal, and chemical properties. As a result of these characteristics, titanium alloys are low machinability materials. Furthermore, when the purpose is an improvement in the machinability, machining path strategies have proven their influence over surface finishing, machining forces, and tool life. The majority of studies have shown the impact of the path strategies on frontal milling processes, and few of them are related to side milling. Finally, based on the Self-Propelled Rotary Tool (SPRT) technique, this work evaluates surface finishing behavior, machining forces, and tool life using two different path strategies (sinusoidal and linear) on the side milling of Ti-6Al-4V alloy. The results show that an adequate strategy and cutting conditions could improve surface finishing, decreases cutting forces, and increases tool life significantly without productivity loss.

Keywords side milling machining strategies tool wear machining forces WP3.42 Performance analysis of a novel in-situ magnetorheological honing process for finishing the internal surface of tubular workpieces

Sunil Kumar Paswan, Anant Kumar Singh Thapar Institute of Engineering and Technology, India

Abstract

The internal surface finish of tubular workpieces enhances the resistance for corrosion, wear, friction and chemical damages. The fine finished tubular workpieces are used as cylindrical dies, molds, pneumatic as well as hydraulic cylinders, cylindrical-barrels, and cylinders for the flow of high purity liquids or gases with better service life. From the very beginning of the manufacturing of tubular parts to their final nano-finished internal surface, it uses various tools that cost a lot. Also, the different workstations associate with a great probability of producing faulty end products. Therefore, to sort out such problems, a novel in-situ tool is designed and fabricated where it is possible that a single tool can perform both traditional as well as advance finishing on the internal surface of the tubular parts at the same workstation. The tool is made up of traditional honing stones and permanent NdFeB magnets. The honing stones finish the internal tubular surfaces through the traditional honing method and the magnets finish the surfaces through the magnetorheological honing method. The finishing wear mechanism is analyzed with the newly designed in-situ tool. The analytical results are confirmed with the experimentations performed using the in-situ tool. The initial coarse workpiece surface is finished with the honing stone of the in-situ tool. Further, the surface is finished through the magnetorheological method of finishing with the permanent magnets of the same in-situ tool. The significant improvement in the finished internal surface of tubular workpieces with a finishing rate of approximately 12 nm/min is achieved. The significant improvement in scanning electron micrographs, circularity images, hardness and reduction in roughness profile as well as waviness of the final finished internal surface of tubular workpieces ensures a higher extent of wear resistance in the internal surface of tubular workpieces which is crucial for their high-performance industrial applications. Keywords

In-situ tool honing magnetorheological finishing wear mechanism WP3.43 Friction and wear mechanisms in coated forming tools

Amanda Tavares1, Angelica Lopes2, Edith Aryel Mesquita1, Diego Almeida2, João Henrique Souza2, Henara Costa1 1Federal University of Rio Grande, Brazil. 2Bruning Tecnometal, Brazil

Abstract

Metal forming involves relative motion between a tool and a workpiece under very high contact pressures, thus possibly leading to severe tool wear, compromising the process stability and the quality of the final product. Despite being fundamental for forming, friction must be controlled to ensure stable forming conditions and reduced energy losses, often achieved by coating the tools. This work analyzed the tribological behavior of commercial thin hard PVD coatings used in metalforming tools. It identified wear mechanisms via scanning electron microscopy (SEM) and 3D topographic characterization before and after strip drawing tests, which were then correlated with friction coefficient measurements. Eight tool materials and three different coatings were tested: VN, TiCrN and TiAlN. The tools were classified into four groups according to their manufacturing process: sintered, rolled, cast and recast. They were initially characterized by SEM, optical interferometry and microhardness. It was shown that the VN coating was rougher, whereas TiCrN and TiAlN followed the substrate topography. The strip drawing tests showed that the VN and TiCrN coatings presented lower and more stable friction coefficient values, which was traced back to the formation of relatively smooth and partially oxidized transfer layers on the tool, leading to more favorable tribological conditions. The TiAlN coating presented higher and very unstable friction values, apparently due to protruding transfer layers, which increased friction and eventually led to galling. The best performance was attributed to the tools coated with TiCrN since the friction values were very stable along the tests. The tools coated with TiAlN presented the worst tribological performance, despite their initially smoother surfaces.

Keywords metalforming tools PVD coatings wear mechanisms friction WP3.44 Influence of particle attrition on erosive wear of bends in dilute phase pneumatic conveying

Yassin Alkassar1, Vijay K Agarwal1, R. K Pandey1, Niranjana Behera2 1Indian Institute of Technology Delhi, India. 2VIT University, India

Abstract

Bulk materials like sand particle/alumina, which do not possess good air retention properties or high permeability are generally conveyed in dilute phase, suspension flow in conventional pneumatic conveying systems. High inlet conveying air velocity is thus necessary to successfully convey such materials. As a result of high air velocity, the particles impact on the bend surface causes erosion of bends and attrition of particles. The study of bend erosion has been a subject of research for a long time and the influence of various operating parameters has been widely investigated. The authors have carried out an extensive experimental plan to study the influence of recirculation of material on the erosion of bends and attrition of particles. It is expected that the severity of erosion may go down as the particles lose sharp edges due to the recirculation of material. The experiments were conducted with silica sand having a mean particle size of 435 micron as abrasive erodent particles in the pilot plant. The pipeline test loop is 48 m long and of 67 mm inner diameter. The bends were placed in horizontal-horizontal orientation with R/d ratio of 4.0. The solid particle erosion behavior of three test bends (B1, B2 and B3) and particle degradation have been analyzed for a total of 29 runs with each batch conveying 300 kg material. The mass loss and bend wall thickness were regularly monitored. Material sample during each run was collected to assess the extent of particle attrition and changes in the particle morphology. This paper presents the experimental results of a comprehensive analysis of the erosion and particle degradation with a change in particle morphology. A correlation has been developed between the extent of material recirculated through the test pipeline and its influence on the erosion of bends and degradation of particles.

Keywords

Pneumatic conveying Dilute phase Particle degradation Erosive wear WP3.45 Degradation of superheater alloys by erosion-corrosion at 550°C under biomass-firing conditions

Raluca Pflumm1, Lukas Mengis1, Kamila Armatys Armatys2, Burkart Adamczyk2 Adamczyk2, Mathias Galetz3 1Dechema Research Institute, Germany. 2Bundesanstalt für Materialforschung und -prüfung, Germany. 3Dechema Research Institut, Germany

Abstract

Fluidised bed technology is often used in energy production with biomass as fuel. For such processes severe corrosion problems along with erosion are characteristic due to the high content of solid particles in the flue gas in conjunction with chlorine-rich species released during the combustion process. This paper discusses the performance of the commonly used IN 625 (2.4856) in comparison to several more cost-efficient Fe- and FeNi- based alloys, which are rich in silicon and refractory metals. The experimental approach includes experiments that combine corrosion with erosion. As a corrosive-erosive medium, ash from a biomass-firing facility in Germany was used. Tests at 550°C were conducted in a furnace with a quartz reactor which performs 320 degree rotations to simulate erosion. For a better understanding of the different degradation mechanisms additional tribological tests were conducted at 550°C on a pin-on-disc tribometer to evaluate the wear resistance of the alloys and of the oxide scales they form. Finally, stationary corrosion experiments in a gaseous atmosphere typical for biomass firing (i.e. 2.5HCl-17H2O-5O2-N2, vol.%) were conducted without erosion. Detailed analysis of metallographic cross-sections is used to clarify and separate the observed degradation mechanism. The results presented are discussed in view of the influence of Ni, Si and refractory metals (with emphasis on Mo) on the scale formation and on the resistance of the investigated materials.

Keywords biomass firing erosion-corrosion high temperature