Mechanical Properties of Trip Aided Bainitic Ferrite TBF Steels in Production and Service Conditions

Year 2018, Volume: 5 Issue: 3, 231 - 237, 30.09.2018

Eren Billur Semih Karabulut İmren Öztürk Yılmaz Samet Erzincanlıoğlu Hafize Çelik Evren Altınok Tanya Başer

https://doi.org/10.17350/HJSE19030000100

Cited By: 1

Abstract

I n the automotive industry, one of the most common methods to reduce the weight of the body components is to downgage the sheets using higher strength steels. In the design phase, engineers typically use the material properties of the incoming material, such as the yield strength and the elongation. For forming analyses, however, more detailed characterization is required flow curves, anisotropy, forming limit curves, etc. . Once the components are formed in the press shop, the yield strength increases due to work strain hardening. The parts are then welded in the body shop, and the body-in-white goes to the paint shop where it is baked to cure the paint. Most steels’ yield strength changes during this paint bake cycle, which determines its final properties in service. Bake hardening and in some cases, bake softening is measured by Bake Hardening Index BHI as defined by EN 10325-2006. The standard dictates relatively low pre-strain 2% and baking temperature 170°C . In real production conditions however, higher strains are achieved and baking temperatures may exceed 170°C to shorten the baking time. In this study, a new generation Advanced High Strength Steel AHSS grade TBF 1050 was characterized for metal forming purposes and its bake hardening response was studied both as the standard suggests and as the real production cycle dictates

Keywords

Advanced High Strength Steels, Material Characterization, Metal Forming, Elastic/Plastic Properties, Bake Hardening

References

• 1. Taub AI, Luo AA, Advanced lightweight materials and manufacturing processes for automotive applications. MRS Bulletin 40/12 (2015) 1045-1054.
• 2. Robert H and Scherre JM, New Peugeot 3008. Proceedings of EuroCarBody 2016, (2016), Bad Nauheim, Germany.
• 3. Senuma T, Physical Metallurgy of Modern High Strength Steel Sheets, ISIJ International 41/6 (2001) 520-532.
• 4. Billur E, Altan T, Three generations of advanced high-strength steels for automotive applications, Part I. Stamping Journal, Nov.- Dec., (2013) 16-17.
• 5. Pichler A, Hebesberger T, Krizan D, Winkelhofer F, Fruber M, Walch C, 3rd Generation of AHSS Grades: A New Family of Steel Grades with a Significantly Improved Balance between Strength and Formability. Proceedings of Materials in Car Body Engineering 2014, (2014), Bad Nauheim, Germany.
• 6. Araki K, Takada Y, Nakaoka K, Work hardening of continuously annealed dual phase steels. Trans. Iron Steel Inst. Jpn. 17/12 (1977) 710-717.
• 7. ThyssenKrupp Stahl AG, Höherfester Stahl für den AutomobilLeichtbau. ThyssenKrupp Stahl, No: 2045, (1999), Duisburg.
• 8. Ramazani A, Bruehl S, Gerber T, Bleck W, Prahl U, Quantification of bake hardening effect in DP600 and TRIP700 steels. Materials & Design 57/C (2014) 479-486.
• 9. Zackay VF, Parker ER, Fahr D, Busch R, The enhancement of ductility in high-strength steels. ASM Trans Quart 60/2 (1967) 252- 259.
• 10. Samek L, Krizan D, Steel--material of choice for automotive lightweight applications. Metal Review (2012) 1-6.
• 11. Grässel O, Frommeyer, G, Effect of martensitic phase transformation and deformation twinning on mechanical properties of Fe-Mn-SiAl steels. Materials Science and Technology 14/12 (1998) 1213-1217.
• 12. Billur E, Çetin B, Uğuz RO, Davut K, Arslan E, Advanced Material Characterization of TWIP Steels. Proceedings of New Developments in Sheet Metal Forming (2016) 303-318.
• 13. Davenport M, Third-generation advanced high strength steel emerges, Stamping Journal, Sept.-Oct., (2017) 22-28.
• 14. Branagan D, Overview of a New Category of 3rd Generation AHSS. Presented at Great Designs in Steel 2013, May 1, Livonia, MI, USA 2013.
• 15. Altan T, Tekkaya AE. Sheet metal forming: processes and applications, ASM International, 2012, ISBN:978-1615038442.
• 16. Fonstein N. Advanced High Strength Sheet Steels, Springer, 2015.
• 17. Sugimoto K, Mukherjee M, Chapter 8 - TRIP aided and complex phase steels, in: Automotive Steels, Rana R, Singh, SB (eds.)Woodhead Publishing, pp. 217-257, 2017.
• 18. Li SH, Dan WJ, Zhang WG, Lin ZQ, A model for strain-induced martensitic transformation of TRIP steel with pre-strain, Computational Materials Science 40/2 (2007) 292-299.
• 19. Stillger M, Brenne T, Feasibility-Simulation and Systematic Process Improvement of Hot Forming Parts as well as Mapping of Results to Vehicle Simulation, in: Proceedings of New Developments in Sheet Metal Forming 2016 (NEBU 2016), pp. 213-230, 2016.
• 20. European Committee for Standardization, EN 10325:2006: Steel - Determination of yield strength increase by the effect of heat treatment [Bake-Hardening-Index], 2006.
• 21. ArcelorMittal, Dual Phase Steels,, Product Brochure, 2017.
• 22. SSAB, Docol 590DP,, Product Brochure, 2017.
• 23. Voesatlpine Steel Division, Dual-Phase Steels,, Product Brochure, 2017.
• 24. Jonason, P, Aluminium intensive door - Mixmetal door structure, Presented at Doors and Closures in Car Body Engineering 2010, Bad Nauheim, Germany, 2010.
• 25. Flaxa V, Schulz T, Schulz S, Mohrbacher H, Entwicklung eines modularen Legierungskonzeptes für HDG DP-Stähle nach VDA239, 2013.
• 26. Pradhan, R, Dent-Resistant Brake-Hardening Steels for Automotive Outer-Body Applications, in SAE Technical Paper, SAE:910290, 1991.
• 27. Pereloma E, Timokhina I, Chapter 9 - Bake hardening of automotive steels, in Automotive Steels, in: Automotive Steels, Rana R, Singh, SB (eds.) Woodhead Publishing, pp. 259-288, 2017.
• 28. Kilic S, Ozturk F, Sigirtmac T, Tekin G, Effects of Pre-strain and Temperature on Bake Hardening of TWIP900CR Steel, Journal of Iron and Steel Research 22/4 (2015) 361-365.
• 29. Robertson LT, Hilditch TB, Hodgson PD, The effect of prestrain and bake hardening on the low-cycle fatigue properties of TRIP steel, International Journal of Fatigue 30/4 (2008) 587-594.
• 30. Dickie RA, Bauer DR, Ward SM, Wagner DA, Modeling paint and adhesive cure in automotive applications, Progress in Organic Coatings 31/3 (1997) 209-216.
• 31. Weenink W, Car Plants Order New Paint Shops, Automotive News Europe, 23 June 1997.
• 32. Bleck W, Bruhl S, Bake hardening effects in advanced high strength steels. In New Development on Metallurgy and Applications of High Strength Steels, 2008.
• 33. ArcelorMittal, Steels for cold stamping -Fortiform®,, Product Brochure, 2014.
• 34. Galdos L, de Argandoña ES, Mendiguren J, Gil I, Ulibarri U, Mugarra, E, Numerical simulation of U-Drawing test of Fortiform 1050 steel using different material models, Procedia Engineering 207 (2017) 137-142.
• 35. Bollen B, The Impulse Excitation technique,, in AMAP Colloquium, Aachen, Germany, 2017.
• 36. Banabic D, Sester M, The Influence of the Constitutive Equations on the Accuracy of Sheet Metal Forming Processes Simulation, in Die and Mold, Ankara, Turkey, 2011.
• 37. Xu L, Barlat F, Disk compression testing and constitutive modeling of TWIP sheet sample. In: Proceedings of ICTP (2008) 2312-2317.
• 38. Barlat F, Brem JC, Yoon JW, Chung K, Dick RE, Lege DJ, Pourboghrat F, Choi S-H, Chu E, Plane stress yield function for aluminum alloy sheets—Part 1: Theory, International Journal of Plasticity 19/9 (2003) 1297-1319.