Energy efficient manufacturing chain for advanced bainitic based on thermomechanical processing

Prof. Dr. Alexandre da Silva Rocha, Laboratório de Transformação Mecânica – UFRGS Prof. Dr.-Ing. Hans-Werner Zoch – Stiftung Institut für Werkstofftechnik - Bremen Working team

IWT - Bremen working team:

Prof. Dr.-Ing. Hans-Werner Zoch UFRGS - Porto Alegre working team: Dr.-Ing. Jérémy Epp Dr.-Ing. Matthias Steinbacher Prof. Dr. Alexandre da Silva Rocha Dr.-Ing. Heinrich Klümper-Westkamp Prof. Dr. Rafael Menezes Nunes Capes Dr.-Ing. Juan Dong Prof. Dr. Lírio Schaeffer M. Sc. Marian Skalecki Prof. Dr. Afonso Reguly 88887.142484/2017 Prof. Dr. Nestor Heck Dr. Eng. Alberto Guerreiro Brito DFG ZO140/21-1 Msc. Rafael Luciano Dalcin Msc. Rodrigo Afonso Hatwig Msc. Thiago Marques Ivaniski Eng. Antonio Carlos de Figueiredo Silveira Eng. Tâmie de Souza Perozzo

Slide 2 Introduction  The waste of Energy in Brazil in the last 3 years reached the amount of about EU 16.2 billion.  Brazil is appointed as the top country in Energy waste in the Industry. Ovens and boilers are the main responsible in the Industry for the high amount of energy waste.  In Brazil, governmental programs as Inovar Auto implemented a politics to force companies to reduce vehicles fuel consumption, installation of safety equipment. Rota 2030 will also increase investment in R&D and is being waited for next year.  As it is well known, development and application of materials and processes to Source: Assoc. das Empresas de Serv. De Conservação de achieve higher strength to weight ratios is Energia. essential to decrease fuel consumption.

Slide 3 Motivation Introduction

 Usually in the manufacturing of automotive components a high amount of energy is used in the heating of the material for hot forging or in the conditioning of the material for warm or cold forging.  Besides that the material has to be heat treated to achieve the desired mechanical properties, what normally involves Q&T with additional energy consumption.  Finally, a surface treatment is needed to improve the surface related properties, as wear and fatigue resistance. Slide 4 Manufacturing routes for forged automotive parts Introduction

Hot forging

Quenching • Q&T or surface • • I.H.

Tempering

Machining

Aditional • . surface • Nitrocarburizing treatment • Oxinitring

Slide 5 Typical Manufacturing Route in Hot-forging Introduction

• 30 T°T° hours Elevated amount of Spheroidizing • Easier energy necessary to to Forge spheroidizing.

Phosphatizing

• Improved Cold Forging Mechanical Properties

Finish Machining

• 8 hours Gas • Quenchi Carburizing ng

• 2 hours • Error possibility of heat treatment

Slide 6 Typical Route in Cold Forging Introduction

Conventional and Slide 7 New-generation bainitic steels

Research Steel grade C[%] Mn[%] Si[%] Cr[%] YS [MPa] Rm [MPa] Strain[%] 70 Institute 60 0.2%C 20MnCrMo7 0,22 1,72 0,49 1,6 860 1250 14 EZM

(%) 0.3%C 50 IF IF-HS HDB 0,17 1,52 1,46 1,32 782 1167 12,5 RWTH 40 MILD Advanced Bainitic BH Steels Solam B1100 <0,2 <1,9 <1,5 >700 >1100 >15 Arcelor

30 C-Mn TRIP 18MnCr5-3 Elongation DP, CP Metasco MC 20 0,25 1,3 0,9 0,8 >700 >1000 >15 Ascometal

HSLA 25MnCrSiVB6 Total Total 10 MARTENSITIC H2/mod. 0,16 1,25 800 1050 16 Hirschvogel 0 16MnCr5 0 200 400 600 800 1000 12001400 1600 HSX 130HD 0,17 1,5 1,2 1,2 1030 1170 16,2 Swiss Steel Yield Strength (MPa) LUT–1 0,20 1,3 0,5 1,1 850 1100 15 Uni Leoben 20MnCr5

Slide 8 New-generation bainitic steels

Si

Slide 9 Objectives of the project  Development of process routes using continuous cooling bainitic steels aiming at energy consumption reduction and improved mechanical and surface properties for automotive and machine parts.

Determination of the processes window for some of the new continuous cooling bainitic steels;

Detection (e.g. by Eddy-Current Analysis) of the ongoing phase transformations during cooling from forging temperature;

Adjusting microstructure by thermomechanical processing;

Improvement of surface related properties (wear and friction) by developing specific surface treatments.

Slide 10 Methodology

Materials of analysis: (Bs) temperature reduction;

 Swiss Steel HSX 130; It promotes enrichment of austenite in Swiss Steel HSX 130 carbon during bainitic transformation; C Mn Si Cr It allows lower cooling rate on CCT diagram, 0,17% 1,50% 1,20% 1,20% good for thermomechanical process.

 A steel with a higher carbon content;  A steel obtained by Spray Forming process and/or by carbon enrichment.

Slide 11 Materials of analysis Methodology  Route 1 - Forging above austenitizing temperature with T forging a, b, c: different cooling rates; different continuous cooling rates T R.T.: room temperature; until room temperature with : forging; posterior cold forging process with T T inter.: intercritical temperature; aust. I : Calibration low deformation rates (calibration). – Expected microstructure: Bainite + Tinter. martensite + low quantities of retained austenite. Bs a b c Bf

R.T I

t

Slide 12 Thermomechanical process routes Methodology

 Route 2 – Forging above austenitizing temperature (I) with posterior forging at intercritical temp. (II). – Expected microstructure: Hardened ferrite + retained austenite + martensite + bainite (greater quantities).

 Route 3 – Forging (I) with posterior warm forging in I the bainitic field (III). II – Expected microstructure: Retained austenite + martensite + bainite (greater quantity). III  Route 4 – Austenitizing and a single forging step in the bainitic field (III). – Expected microstructure: Bainite and retained austenite.  Route 5 – Austenitizing and single forging at the intercritical field (II). – Expected microstructure: Hardened ferrite + retained austenite + martensite + bainita.

Slide 13 Thermomechanical process routes Methodology

Slide 14 Surface Modification Methodology

 WP1 (a+b): Material acquisition and preparation of samples (IWT + UFRGS) – 11/17 to 01/18  Material acquisition (IWT and UFRGS);

 Manufacturing of the samples and preliminary heat treatment. (IWT and UFRGS);

 WP2: Experimental simulation of thermo-mechanical process and in-process analysis of microstructure (IWT) – 11/17 to 05/18  Thermo-mechanical process with simplified sample geometry;

 In-process microstructure control by eddy-current sensor technique;

 Description of phase transformation kinetics and modeling;

Slide 15 Working packages Methodology

 WP3: Analysis of microstructure evolution via in-situ synchrotron XRD experiments (IWT) – 04/18 to 11/18

X-ray diffraction experiments during thermomechanical treatments for evaluation of:

Phase transformations;

Crystallite size evolution;

Residual stresses;

Crystallographic texture; Experimental device for thermomechanical treatments at European Synchrotron Radiation Facility (Grenoble, France).

Carbon content in solution based on lattice parameter evolution;

Slide 16 Working packages Methodology

 WP4: FEM Forging simulation (UFRGS) – 11/17 to 05/18 Finite element simulation;

Data crossing between simulation results, Gleeble data and thermodynamical simulations aiming to plan thermo-mechanical treatments;

 WP5: Determination of Heat Transfer Coefficients - HTC (IWT + UFRGS) – 12/17 to 04/18

Time-Temperature cooling curves acquisition;

Q-Probe;

Thermo-mechanical simulation;

 Evaluation of boundary conditions for the heat transfer between die and workpiece;

Slide 17 Working packages Methodology

 WP6: Thermo-mechanical Experiments (UFRGS + IWT) 04/18 to 11/18 Experimental forging in the different established routes;

Adaptation of Presses;

Manufacturing of Dies;

Instrumentation;

Development of cooling devices;  WP7: Mechanism-based definition of process window (IWT + UFRGS) – 02/18 to 01/19

Parameters definitions based on the previous results;

 WP8: Post surface-strengthening treatments (IWT + UFRGS) – 10/18 to 11/19 ;

Plasma Nitriding;

Deep Rolling;

Slide 18 Working packages Methodology  WP9: Experimental characterization of the treated samples (IWT + UFRGS) 01/18 to 04/19 Metallographic analysis (MO & SEM); X-Ray Diffraction; Hardness tests; Wear tests; GDOES; Compression and Tensile tests; Fatigue tests;

 WP10: Project management (UFRGS + IWT) – during all the project. Student exchange supervision;

On-line meetings;

National and international conferences;

Slide 19 Working packages Time schedule

(2018 -2019) Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May WP1: Steel acquisition, confection and IWT X X X X sample characterization. UFRGS X X X X X WP2: Experimental simulation of the IWT processes. UFRGS IWT X X X WP3: DRX experiments in-situ. UFRGS IWT WP4: Forging simulation. UFRGS IWT WP5: Heat transfer coefficients. UFRGS IWT WP6: Thermomechanical experiments. UFRGS IWT WP7: Definition of the window process. UFRGS IWT WP8: Post superficial heat treatment. UFRGS IWT WP9: Characterization tests. UFRGS IWT WP10: Project management. UFRGS

Slide 20 Working plan for the extended period: ퟑ풓풅 and ퟒ풕풉

 Steel production by Spray forming.  Carbon Enrichment of Samples.  Forging of real/model parts with numerical simulation of the forging process.  Mechanical testing of the produced parts.  Final development of surface treatments for the produced parts and evaluation of wear and fatigue properties.

Slide 21 Student missions

5th 7th 8th Study Missions 1th Trimester 2nd Trimester 3rd Trimester 4th Trimester 6th Trimester Trimester Trimester Trimester Msc. Rodrigo Hatwig Eddy-Current analysis, Gleeble Route definition, steel Doctorate degree 2 characterization Eng.Tâmie Perozzo Dilatometry, XRD Master Degree 2 Heat-transfer coefficient Master Degree 3 Surface treatments Graduation degree 1 Steel characterization Thermomechanical Graduation degree 2 experiments Graduation degree 3 Forged steel characterization Microstructure analysis during Post Doctoral thermomechanical processing

Slide 22 We would like to acknowledge the German Research Council (DFG) and CAPES for funding of the projects Capes 88887.142484/2017 and DFG ZO140/21-1

Thank you for your attention!

Slide 23