DOCSLIB.ORG

The Use of Various Peening Methods to Improve the Fatigue Strength of Titanium Alloy Ti6al4v Manufactured by Electron Beam Melting

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Use of Various Peening Methods to Improve the Fatigue Strength of Titanium Alloy Ti6al4v Manufactured by Electron Beam Melting AIMS Materials Science, 5(5): 1000–1015. DOI: 10.3934/matersci.2018.5.1000 Received: 21 August 2018 Accepted: 23 October 2018 Published: 29 October 2018 http://www.aimspress.com/journal/Materials Research article The use of various peening methods to improve the fatigue strength of titanium alloy Ti6Al4V manufactured by electron beam melting Hitoshi Soyama* and Yuya Okura Department of Finemechanics, Tohoku University, 6-6-01 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan * Correspondence: Email: [email protected]; Tel: +81227956891. Abstract: Additive manufacturing (AM) of metals is one of the foremost methods used for making medical implants and components for aviation. However, the fatigue strength of AM metals is weaker than that of the bulk equivalent. Mechanically treating the surface, such as by shot peening, can improve the fatigue strength, and novel peening methods without shot have also been proposed. In this paper, in order to demonstrate the improvements made in AM metals by various peening methods, specimens made of titanium alloy Ti6Al4V manufactured by electron beam melting (EBM) were treated by shot peening, laser peening and cavitation peening, then assessed by a plate bending fatigue test. In the case of shot peening, the shots were accelerated by a water jet to mitigate the incidence of dust during the process. For laser peening, the specimen was placed in water, and the effect of the impact produced at the target due to collapsing bubbles, which developed after laser ablation of the surface, was greater than the effect due to the laser ablation itself. For cavitation peening, the cavitation was generated by injecting a high speed water jet into water. In each case improvements in the fatigue strength of the Ti6Al4V were made. Improvements of 104% by laser peening, 84% by cavitation peening and 68% by shot peening compared with a non-peened specimen were achieved. Keywords: mechanical surface treatment; medical implant; titanium alloy; additive manufacturing; electron beam melting; fatigue strength; shot peening; laser peening; cavitation peening 1. Introduction Additive manufacturing (AM) of metals is an attractive process for manufacturing medical 1001 implants and aviation components, in the first case because it is easy to make implants that are an order more porous [1] and in the second case because the weight of components can be reduced by the increased design freedom without having to consider machining [2]. Unfortunately, the fatigue strength of AM metals is significantly less than that of their bulk counterparts [2,3]. It has been reported that mechanically treating the surface, such as by shot peening, can improve the fatigue strength of AM metals [2,3]. However, a comparison between the improvements made to the fatigue strength of AM metals by conventional shot peening and novel peening methods, such as laser peening [4–6] and cavitation peening [7], has not been done. Therefore, we carried out an experimental investigation of the use of shot peening, laser peening and cavitation peening to improve the fatigue strength of Ti6Al4V manufactured by an electron beam melting method. As is well known, additive manufacturing, which is also called direct manufacturing, such as by electron beam melting and/or selective laser melting, is suitable for the manufacture of medical implants, since porous implants can be produced and they can be made based on the needs of each individual patient. However, the fatigue strength and/or fatigue life of AM metals is much smaller than that of bulk materials because of the surface roughness. It has been reported that the fatigue life of titanium alloy Ti6Al4V produced by additive manufacturing, rolling and casting decreased as the maximum surface roughness increased [8]. Several methods, including electron beam melting (EBM), selective laser melting (SLM), laser engineered net shaping (LENS) and a wire feed method have been proposed [9,10]. The advantage of EBM is that the build rate is normally larger than that of SLM [9,11]. However, the fatigue strength of EBM materials is smaller than that of SLM materials [9,10,12], as the roughness of the surface is greater [10]. Thus, the main purpose of the present paper is to improve the fatigue strength of titanium alloy Ti6Al4V manufactured by EBM. It has been reported that the fatigue strength and/or fatigue life of titanium alloy Ti6Al4V manufactured by EBM can be improved by shot peening and cavitation peening [2,3]. The conventional method for mechanically treating a surface is shot peening. As mentioned above, shot peening can improve the fatigue strength of AM metals [2,3]. However, shot peening produces dust due to collisions between the shot, and the dust causes dust explosions [13] and a health hazard. In order to avoid these risks, a shot peening technique using recirculating shot accelerated by a water jet was established [14]. This technique was used in this study for shot peening. In the case of laser peening, there are two major methods. One method is to use a powerful pulsed laser, such as one with several J per pulse, to treat the surface, which is covered by a sacrificial layer of tape or paint. In this method, a liquid film is formed on the surface [4,6]. The other method is submerged laser peening which obviates the need for a sacrificial layer [5]. In either case, it is considered that a laser induced shock wave in the liquid results in the material being treated. As is well known, in the case of submerged laser peening, a bubble is generated after laser ablation, and this bubble develops, then collapses, and as its collapse it erodes the surface, the same as cavitation bubble [7]. Thus, in this paper, this process, which follows laser ablation, is called “laser cavitation”. Using a submerged shock wave sensor to measure the pressure amplitude in the water showed that the pressure induced by laser ablation was larger than that by laser cavitation [15]. However, when the force due to the impact was measured by a special homemade sensor developed to evaluate cavitation impact [16,17], the amplitude of the impact induced by laser cavitation was 1.5 times larger than that due to laser ablation [7]. That is, when laser cavitation is considered and optimized, we get two hits, i.e., from laser ablation and laser cavitation, with a single pulse. Thus, in AIMS Materials Science Volume 5, Issue 5, 1000–1015. 1002 the present experiment, the submerged laser peening system was used. In the case of cavitation peening, shots are not required. Thus chemical cleaning to remove material transferred to the surface from the shots is unnecessary. Moreover, since cavitation peening can be used to treat the inner walls of a tube by placing it parallel to the jet axis [18], it can be used in the manufacture of porous medical implants. It has been reported that the fatigue strength of spinal implants made of titanium alloy was improved by cavitation peening [19]. Note that the mechanism for cavitation peening is different to that of water jet peening, in which the impacts of water columns are used to create plastic deformation [20]. Even though the water jet is submerged, the surface can be treated by water jet peening. In the case of water jet peening, a powerful plunger pump with an injection pressure of several hundreds of MPa is required. On the other hand, in the case of cavitation peening, the injection pressure required for a cavitating jet is about one tenth of the pressure required for water jet peening [21]. Thus, risk of surface damage to the implants by cavitation peening is negligible compared to water jet peening, and also the initial and running costs of cavitation peening are less than one tenth of those of water jet peening. Thus, in the present experiments, the effect of cavitation peening using a submerged water jet was investigated. As mentioned above, the impact mechanism to produce local plastic deformation is different for each peening method [20]. The impact of shot with the surface is used in shot peening, whereas the impact induced by laser ablation and laser cavitation are utilized for submerged laser peening, and the impact induced by cavitation bubbles collapsing is used in cavitation peening. Thus, the strain rate for each peening method is different. It has been reported that the plastic deformation in the material and the surface roughness are different when the strain rate of the peening method is different [22]. Thus it is worthwhile investigating the improvements made in the fatigue life and/or fatigue strength of the AM metals used for medical implants by the different peening methods. In this study, to compare the improvements made in the fatigue strength of an AM metal manufactured by EBM by the various peening methods, we used fatigue test specimens made of titanium alloy Ti6Al4V. These specimens were treated by shot peening, submerged laser peening and cavitation peening, then assessed by a plate bending fatigue test. Note that all the test specimens were heat-treated to improve the fatigue strength, as the fatigue strength of specimens without heat-treatment was considerably smaller than that of heat-treated specimens. 2. Experimental apparatus and procedures 2.1. Titanium alloy Ti6Al4V manufacture by EBM Figure 1 illustrates the geometry of the specimens used for the plate bending fatigue tests. All the specimens were manufactured by EBM. The powder used in the EBM process was made of Ti6Al4V and had an average diameter of about 75 m. The spot size of the electron beam for selective melting was 0.2 mm in diameter, and the stacking pitch was 90 m. The specimens, as shown in Figure 1, included 4 holes.
Load more

Recommended publications
  • Peening Weld Surfaces with Steel Shot Induces Compressive Stresses That Raise Resistance to Fatigue and Corrosion
    Peening weld surfaces with steel shot induces compressive stresses that raise resistance to fatigue and corrosion. By Tom Floyd hot peening improves Testing shot-peened parts, re- Built-in compressive stresses property performance searchers have demonstrated that raise resistance to stress corrosion of welds and weld- peening raises fatigue resistance of by counteracting tensile stresses. mentsS by cancelling residual tensile fillet welds in carbon steel and butt Stress corrosion occurs when tensile stresses that develop in surfaces as welds in constructional alloy steel stresses break up oxide layers that welds cool and replacing them with by 20 to 40 percent, and can double normally protect surfaces of chro- compressive stresses. Compressive fatigue resistance of butt welds in mium-containing alloys. Though stresses raise resistance to fatigue, aluminum plate and 18-percent Ni bare metal re-oxidizes to form fresh stress corrosion, and intergranular maraging steel. Researchers at Rock- oxide coatings, recurring cycles of corrosion. well International (Atomic Di- tensile stresses continually rupture A cold-working process, shot vision) found that shot peening pre- these layers. peening bombards a metal work- vents stress corrosion cracking of As for intergranular corrosion, piece with spherical pellets, com- weldments in austenitic stainless characteristic of stainlesses sensi- monly steel shot. Each impact steel. tized at weld temperatures, peening stretches and densifies surface lay- Fatigue resistance improves be- before welding helps to prevent it ers. Because subsurface material re- cause, when service imposes tensile by breaking up surface grains. This mains unstretched, it exerts an op- stresses in a part, the built-in com- action provides a multitude of nu- posing force, trying to restore the pressive stresses counteract them.
    [Show full text]
  • Effect of Shot Peening on Fatigue Strength of Maraging Steel
    Transactions on Engineering Sciences vol 39, © 2003 WIT Press, www.witpress.com, ISSN 1743-3533 Effect of shot peening on fatigue strength of maraging steel N. ~awa~oishi',T. ~a~ano~ & M. ~ori~arna~ I Faculty of Engineering, Kagoshima University,Kagoshima, Japan 2 Miyakonojyo National College of Technology, Miyakonojyo, Japan Abstract Rotating bendmg fatigue tests were carried out for a shot-peened maraging steel in order to investigate the effects of shot peening on the fatigue strength and the fracture mechanism focusing on the effect of surface roughness. Fatigue strength was markedly improved by shot peening because of hardening and generation of compressive residual stress in the surface layer. The origin of fatigue fracture changed from the specimen surface at high stress levels to an inclusion in the interior of specimen at low stress levels. And at the middle stress levels, both fracture modes were observed. Consequently, the shape of the S-N curve of shot- peened specimen was complex, corresponding to the change of fracture mode. In the region where surface fracture occurs, polishing the specimen surface and double shot peening using superhard fine particles were effective to improve the fatigue strength through the decrease in stress concentration due to smoothening the specimen surface. Transactions on Engineering Sciences vol 39, © 2003 WIT Press, www.witpress.com, ISSN 1743-3533 100 Surface Twatment V1 1. Introduction Maraging steel is an ultra-high strength steel which has both high tensile strength and high ductility [1],[2]. However, fatigue strength is relatively low in comparison with the hgh static strength [3]. Therefore, the study on the improvement of fatigue strength of maraging steel is important.
    [Show full text]
  • Laser Peening for Prevention of Fatigue Failures
    LASER PEENING FOR PREVENTION OF FATIGUE FAILURES David F. Lahrman Peter A. Gaydos LSP Technologies, Inc. United States ABSTRACT Laser peening is an innovative commercially-available surface enhancement process for increasing the fatigue life of metal components. The process produces deep residual compressive stress into treated surfaces, typically five to ten times deeper than conventional metal shot peening. These deep compressive residual stresses inhibit the initiation and propagation of fatigue cracks. Laser peening has been particularly effective in increasing the resistance to fatigue crack propagation initiated from foreign object damage in titanium alloy fan and compressor blades of aircraft gas turbine engines. [1,2,3,4] However, the potential application of this process is much broader, encompassing automotive parts, orthopedic implants, tooling and dies, and others. Significant progress has been made to lower the cost and increase the throughput of the process, making it affordable for numerous applications. This paper reviews the status of laser peening technology, material property enhancements, and potential applications. KEYWORDS Laser shock peening, fatigue, life, residual stress, surface, enhancement HOW LASER PEENING WORKS Laser peening drives a high amplitude shock wave into a material surface using a high energy pulsed laser. The effect on the material being processed is achieved through the mechanical “cold working” effect produced by the shock wave, not a thermal effect from heating of the surface by the laser beam. The laser system is a high-energy, pulsed neodymium-glass laser system having a wavelength of 1.054 µm. The laser peening system produces very short laser pulses, selectable from 8 to 40 nanoseconds, with a pulse energy of up to 50 joules.
    [Show full text]
  • Finite Element Modelling of Shot Peening and Peen Forming Processes and Characterisation of Peened Aa2024-T351 Aluminium Alloy
    UNIVERSITE´ DE MONTREAL´ FINITE ELEMENT MODELLING OF SHOT PEENING AND PEEN FORMING PROCESSES AND CHARACTERISATION OF PEENED AA2024-T351 ALUMINIUM ALLOY ALEXANDRE GARIEPY´ DEPARTEMENT´ DE GENIE´ MECANIQUE´ ECOLE´ POLYTECHNIQUE DE MONTREAL´ THESE` PRESENT´ EE´ EN VUE DE L'OBTENTION DU DIPLOME^ DE PHILOSOPHIÆ DOCTOR (GENIE´ MECANIQUE)´ SEPTEMBRE 2012 © Alexandre Gari´epy, 2012. UNIVERSITE´ DE MONTREAL´ ECOLE´ POLYTECHNIQUE DE MONTREAL´ Cette th`eseintitul´ee : FINITE ELEMENT MODELLING OF SHOT PEENING AND PEEN FORMING PROCESSES AND CHARACTERISATION OF PEENED AA2024-T351 ALUMINIUM ALLOY pr´esent´ee par : GARIEPY´ Alexandre en vue de l'obtention du dipl^ome de : Philosophiæ Doctor a ´et´ed^ument accept´eepar le jury d'examen constitu´ede : M. GOSSELIN Fr´ed´eric, Doct., pr´esident M. LE´VESQUE Martin, Ph.D., membre et directeur de recherche M. BOCHER Philippe, Ph.D., membre et codirecteur de recherche M. CHAMPLIAUD Henri, Ph.D., membre Mme ROUHAUD Emmanuelle, Ph.D., membre iii A` ma famille iv ACKNOWLEDGEMENTS I would like to first thank Pr. Martin L´evesque and Claude Perron for their guidance and trust throughout this project. Your confidence allowed me to explore hypotheses that made my work interesting, challenging and, I hope, useful. I would also like to thank Pr. Philippe Bocher at Ecole´ de Technologie Sup´erieure for welcoming the computer savvy mechanical engineering student I was in his group and introducing me to the fascinating field of materials science. The time and expertise provided by the National Research Council Canada - Aerospace is also greatly appreciated. I would like to thank Simon Larose for his generous help and advice and well as Christian Corbeil and Xavier Pelletier for their support.
    [Show full text]
  • Laser Peening Process and Its Impact on Materials Properties in Comparison with Shot Peening and Ultrasonic Impact Peening
    Materials 2014, 7, 7925-7974; doi:10.3390/ma7127925 OPEN ACCESS materials ISSN 1996-1944 www.mdpi.com/journal/materials Review Laser Peening Process and Its Impact on Materials Properties in Comparison with Shot Peening and Ultrasonic Impact Peening Abdullahi K. Gujba 1 and Mamoun Medraj 1,2,* 1 Department of Mechanical and Industrial Engineering, Concordia University, 1455 De Maisonneuve Blvd. W., Montreal, QC H3G 1M8, Canada; E-Mail: [email protected] 2 Department of Mechanical and Materials Engineering, Masdar Institute, Masdar City, P.O. Box 54224, Abu Dhabi, UAE * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +1-514-848-2424 (ext. 3146); Fax: +1-514-848-3175. External Editor: Douglas Ivey Received: 17 October 2014; in revised form: 18 November 2014 / Accepted: 27 November 2014 / Published: 10 December 2014 Abstract: The laser shock peening (LSP) process using a Q-switched pulsed laser beam for surface modification has been reviewed. The development of the LSP technique and its numerous advantages over the conventional shot peening (SP) such as better surface finish, higher depths of residual stress and uniform distribution of intensity were discussed. Similar comparison with ultrasonic impact peening (UIP)/ultrasonic shot peening (USP) was incorporated, when possible. The generation of shock waves, processing parameters, and characterization of LSP treated specimens were described. Special attention was given to the influence of LSP process parameters on residual stress profiles, material properties and structures. Based on the studies so far, more fundamental understanding is still needed when selecting optimized LSP processing parameters and substrate conditions.
    [Show full text]
  • Case Studies of Fatigue Life Improvement Using Low Plasticity Burnishing in Gas Turbine Engine Applications
    Case Studies of Fatigue Life Improvement Using Low Plasticity Burnishing in Gas Turbine Engine Applications Paul S. Prevhy Ravi A. Ravindranath ~revev~ambBa-research.com) ([email protected]) Lambda Research NAVAIR, 22195 Elmer Road 5521 Fair Lane Bldg: 106, Room: 202-G Cincinnati, OH 45227 Patuxent River, MD 20670-1534 Michael Shepard Timothy Gabb [email protected] @[email protected]@ Wright Patterson AFB NASA Glenn Research 2230 Tenth St., Ste. 1 21088 Brookpark, Bldg. 43, Room 231 WPAFB, OH 45433-7817 Cleveland, OH 44135-3191 ABSTRACT fatigue benefit of thermal stability at engine Surface enhancement technologies such as shot temperatures. (LSP), and low plasticity An order of magnitude improvement in damage e substantial fatigue life tolerance of LPB processed Ti-6-4 fan blade improvement. However, to be effective, the leading edges. compressive residual stresses that increase fatigue 0 Elimination of the fretting fatigue debit for Ti-6-4 strength must be retained in service. For successful with prior LPB. integration into turbine design, the process must be Corrosion fatigue mitigation with LPB in Carpenter affordable and eompatible with the manufacturing 450 steel. LPB provides thermally stable Damage tolerance improvement in 17-4PH steel. Where appropriate, the performance of LPB is compared to conventional shot peening after exposure to engine operating temperatures. INTRODUCTION LPB is a new method of surface enhancementCl-4 ] deep stable surface compressive residual compressive residual stress little cold work for improved fatigue, ,and stress corrosion performance even design. ed temperatures where compression from shot The x-ray diffraction based background studies of relaxes.[5] LPB surface treatment is thermal and mechanical stability of surface using conventional multi-axis CNC machine t enhancement techniques are briefly reviewed, unprecedented control of the residual stress demonstrating the importance of -g cold work.
    [Show full text]
  • Laser Peening Vs. Shot Peening: Engineering of Residual Stresses, Surface Roughness and Cold Working
    Laser Peening vs. Shot Peening: engineering of residual stresses, surface roughness and cold working 0. Higounenc1 1 Metal Improvement Company I Curtiss Wright Surface Technologies, Bayonne, France Abstract In Laser Peening (LP), compared to Shot Peening (SP), the magnitude of residual compressive stress at the surface is the same: about 60% of elastic limit; but the depth is much higher. In Low Cycle Fatigue (LCF) depth of residual compressive stress is beneficial because it does not only delay crack initiation, but also crack propagation. Depth of residual stress is also crit­ ical in Foreign Object Damage (FOO) and Crack Grow Rate (CGR) applications. Changes in surface roughness, as soon as cold work, are much more significant in shot SP compared to LP. Those changes can have a positive, or a negative influence depending on application and condition: HCF or LCF, deteriorating or non-deteriorating environment such as corrosion or FOO, fretting, surface contact fatigue. Thus, LP is complementary to SP in some specific applications such as LCF, FOO, CGR. The other advantage is the extremely high process control that allow more easily to take into ac­ count the credit of LP in the design .. Keywords: shot peening, laser peening, fatigue life, crack nucleation, crack propagation Introduction Laser Peening (LP) is a process in which an iintense beam of laser light (irradiance 2 to 1OGW/cm2) is directed on to a sacrificial ablating material placed on the surface of the com­ ponent to be treated. The light rapidly vaporizes a thin portion of the ablative layer, producing a plasma that is confined by the inertia of a thin laminar layer of water (-1 mm thick) flowing over the surface.
    [Show full text]
  • An Overview of Shot - Peening
    International Conference on Shot Peening and Blast Cleaning AN OVERVIEW OF SHOT - PEENING A Niku-Lari· IITT, France. ABSTRACT Controlled shot-peening is an operation which is used largely in the manufacture of mechanical parts. It should not be confused with sand blasting used in cleaning or descaling parts. Shot-peening is in fact a true machining operation which helps· increase fatigue and stress corrosion resistance by creating beneficial residual surface stresses. The technique consists of propelling at high speed ~mall beads of steel, cast iron, glass or cut wire against the part to be treated. The size of the beads can vary from 0.1 to 1.3 or even 2mm. The shot is blasted under conditions which must be totally controlled. The main advantage of this particular surface treatment is that it increases considerably the fatigue life of mechanical parts subjected to dynamic stresses. It has many uses in industry, particularly in the manufacture of parts as different as helical springs, rockers, welded joints, aircraft parts, transmission shafts, torsion bars, etc. At a time when the optimum characteristi_cs are being demanded of mechanical assemblies, shot-peening is a surface treatment method which is being increasingly chosen by engineers. However, shot-peening technology is yet to be fully perfected and the substantial changes produced in the treated material make it difficult at the present time to put the best conditions into practical use. KEY WORDS Residual stress, surface roughness, stress relaxation, Sh.at-size, Shot-velocity, Shot-hardness, Intensity, Fatigue. 1. THE TECHNOLOGY OF SHOT-PEENING 1.1 Shot-Peening Machines There are numerous types of shot-peening machines.
    [Show full text]
  • Dislocation Pinning Effects Induced by Nano-Precipitates During Warm Laser Shock Peening: Dislocation Dynamic Simulation and Experiments" (2011)
    Purdue University Purdue e-Pubs Birck and NCN Publications Birck Nanotechnology Center 7-15-2011 Dislocation pinning effects induced by nano- precipitates during warm laser shock peening: Dislocation dynamic simulation and experiments Yiliang Liao Purdue University, [email protected] Chang Ye Purdue University, [email protected] Huang Gao Purdue University, [email protected] Bong-Joong Kim Purdue University Sergey Suslov Birck Nanotechnology Center, Purdue University, [email protected] See next page for additional authors Follow this and additional works at: http://docs.lib.purdue.edu/nanopub Part of the Nanoscience and Nanotechnology Commons Liao, Yiliang; Ye, Chang; Gao, Huang; Kim, Bong-Joong; Suslov, Sergey; Stach, Eric A.; and Cheng, Gary J., "Dislocation pinning effects induced by nano-precipitates during warm laser shock peening: Dislocation dynamic simulation and experiments" (2011). Birck and NCN Publications. Paper 975. http://dx.doi.org/10.1063/1.3609072 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Authors Yiliang Liao, Chang Ye, Huang Gao, Bong-Joong Kim, Sergey Suslov, Eric A. Stach, and Gary J. Cheng This article is available at Purdue e-Pubs: http://docs.lib.purdue.edu/nanopub/975 Dislocation pinning effects induced by nano-precipitates during warm laser shock peening: Dislocation dynamic simulation and experiments Yiliang Liao, Chang Ye, Huang Gao, Bong-Joong Kim, Sergey Suslov et al. Citation: J. Appl. Phys. 110, 023518 (2011); doi: 10.1063/1.3609072 View online: http://dx.doi.org/10.1063/1.3609072 View Table of Contents: http://jap.aip.org/resource/1/JAPIAU/v110/i2 Published by the AIP Publishing LLC.
    [Show full text]
  • The Method of Corrective Shot Peening : How to Correct the Distortion on the Machined Parts
    The Method Of Corrective Shot Peening : How To Correct The Distortion On The Machined Parts Sutarno and Maris Munthe, Indonesian Aerospace Industry (IAe) Jl. Pajajaran 154 Bandung 40174 Indonesia [email protected], [email protected] Abstract Most of machining process that applied on one side of aircraft parts will leaves the parts in high stress state and this condition is the main causes of distortion. There are several methods that used for correction of the distortion and Corrective Shot Peening is one of them. Corrective Shot Peening is the combination of the art and the rule of thumb by applying of peening principle with S280 and /or S330 steel shot size to induce energy lock by lengthen specific area of the part and this will release the distortion. This paper will prepared the corrective peening method to overcome the distortion on 7000 series of aluminum structural parts which will impact on fit, form, function and parts service life in assembly line Key word : shot peening, correction of distortion, energy lock. a. Introduction Machining processes consists of milling, drilling, turning and boring. Machining process is applied to any kind of raw materials in order to meet the engineering drawing requirements. In milling process especially for one side machining only, will contribute the unbalance in term of residual stress and form a new equilibrium and followed by distortion or defection. To minimize the distortion some improvement will be done such as improvement in machining method (depth of cut ; cutting speed and cooling system). For distortion parts will be corrected by corrective peening method.
    [Show full text]
  • 24 / 7 / 365 Machines
    Spring 2017 Volume 31, Issue 2 | ISSN 1069-2010 ShotThe Peener Sharing Information and Expanding Global Markets for Shot Peening and Blast Cleaning Industries 24 / 7 / 365 Machines Engineered Abrasives® Delivers Three Machines to US Automotive Firm PLUS: ❚ NEW FLAPPER PEENING TOOL ❚ WHEELBLAST EQUIPMENT AND SHOT PEENING ❚ CURVE SOLVER WEB APP ❚ RECYCLING ABRASIVES 2 The Shot Peener | Spring 2017 Spring 2017 | CONTENT 22 PeenSolver: Your Free Curve Solver Web App Electronics Inc. is introducing their PeenSolver Web App. The app is available free of charge, it’s SAE J2597 compliant, and it uses the same curve-fit feature and equations Dr. Kirk developed for the Excel-based program. 26 The Importance of Work 6 According to Dr. Kirk, this article has two Engineered Abrasives recently delivered three machines that objectives: (1) to explain the units that are ready to work 24/7/365 for a US automotive manufacturer. dominate shot peening and (2) to show how the amount and rate of work done affects every shot peening parameter. Only simple 8 arithmetic is invoked—no finite element How a New Product is Developed analysis! Brigitte Labelle, the co-owner of Shockform Aeronautique Inc., shares how the new SPIKER® 38 flapper peening tool went from SAE AMS2590A: The First Revision of the Modern Rotary concept to finished product. Flap Peening Specification Dave Barkley, the sponsor of SAE AMS2590A, describes the revisions to the popular rotary flap peening specification. 12 The Role of Wheelblast in Shot Peening Kumar Balan reviews application-based uses of wheelblast 42 machines for shot peening. Recycling Abrasives Would you like to implement a new recycling program in your organization? Don’t miss this article by Mike Wright, CEO of 18 Wisdom Environmental.
    [Show full text]
  • Quantification of Shot Peening Coverage
    acaDEMIC STUDY by Dr. David Kirk | Coventry University Quantification of Shot Peening Coverage INTRODUCTION A suggested identifying parameter for a shot stream’s Shot peening is essentially a surface metalworking process. A ability to achieve required coverage levels is described in stream of high-energy shot particles does work on the surface some detail. of components. The work done manifests itself in the form of dents. Coverage with dents increases with peening time. 1 PARTICLE WORK CAPABILITY The progress of coverage is illustrated in fig.1. The rate of Each effective shot particle has some capability for doing increase in coverage slows down with increase in the amount work on a component’s surface. This capability depends of peening – following the “Law of Diminishing Returns.” An upon the kinetic energy possessed by the particle. It is not important practical requirement is that the applied shot stream commonly recognized that work units and kinetic energy must achieve a required degree of coverage in an economical units are identical, i.e.: time. As coverage increases a surface layer of work-hardened, The units for work can be expressed as either N*m or compressively-stressed component material is generated. It kg*m2*s-2. is this “magic skin” that promotes improvement in service performance. Work is force (in Newtons) multiplied by distance (in meters) so that: Work units = N*m (1) Kinetic energy, ½mv2, has units of kg (for the mass, m) and of m*s-1 (for the velocity, v). Hence by inserting these units we have that: Kinetic energy units = kg*m2*s-2 (2) Force, which has the unit of Newtons, N, is equal to mass (in kg) multiplied by acceleration – which has units of m*s-2.
    [Show full text]