Effect of annealing temperature on microstructure and mechanical properties of 0.14C-7Mn hot-rolled medium manganese steel

doi:10.13251/j.issn.0254-6051.2023.11.013

Abstract

Abstract: Annealing experiments of the hot-rolled 0.14C-7Mn medium manganese steel were carried out at 600 ℃, 620 ℃ and 640 ℃ for 10 h, respectively. The results show that after annealing, lath ferrite and austenite are obtained. The volume fraction of austenite increases with the increase of annealing temperature, the content of C and Mn in austenite gradually decreases, which leads to the decrease of mechanical stability. The tensile curves of annealed steels show continuous yield. With the increase of annealing temperature, the volume fraction of austenite increases, while the stability decreases, and the martensite produced during deformation increases, so the tensile strength increases. During the deformation process, the continuous transformation of an appropriate amount of reversed austenite with moderate stability leads to work hardening, which delays the generation of neck shrinkage and increases the uniform elongation.

Key words: medium manganese steel, austenite stability, transformation induced plasticity, mechanical properties

CLC Number:

TG161

Wang Tao, Yang Dapeng, Yi Hongliang. Effect of annealing temperature on microstructure and mechanical properties of 0.14C-7Mn hot-rolled medium manganese steel[J]. Heat Treatment of Metals, 2023, 48(11): 83-89.

References

[1]李军, 路洪洲, 易红亮, 等. 乘用车轻量化及微合金化钢板的应用[M]. 北京: 北京理工大学出版社, 2015: 3-23.
[2]Maryam Soleimani, Alireza Kalhor, Hamed Mirzadeh. Transformation-induced plasticity (TRIP) in advanced steels: A review[J]. Materials Science and Engineering: A, 2020, 795: 140023.
[3]杜林秀, 高秀华, 吴红艳, 等. 低碳中锰钢板材住址控制理论及性能[M]. 北京: 冶金工业出版社, 2021: 5-21.
[4]王明明, 马飞, 裴未迟, 等. 汽车用高强塑积中锰钢的研究进展[J]. 金属热处理, 2022, 47(9): 272-280.
Wang Mingming, Ma Fei, Pei Weichi, et al. Research progress of medium manganese steels with high product of strength and elongation for automobile[J]. Heat Treatment of Metals, 2022, 47(9): 272-280.
[5]Yang D P, Du P G, Wu D, et al. The microstructure evolution and tensile properties of medium-Mn steel heat-treated by a two-step annealing process[J]. Journal of Materials Science and Technology, 2021, 75: 205-215.
[6]Cai H L, Chen P, Oh J K, et al. Quenching and flash-partitioning enables austenite stabilization during press-hardening processing[J]. Scripta Materialia, 2020, 178: 77-81.
[7]Wang M M, Tasan C C, Ponge D, et al. Smaller is less stable: Size effects on twinning vs. transformation of reverted austenite in TRIP-maraging steels[J]. Acta Materialia, 2014, 79: 268-281.
[8]Jacques P J, Delannay F, Ladrière J. On the influence of interactions between phases on the mechanical stability of retained austenite in transformation-induced plasticity multiphase steels[J]. Metallurgical and Materials Transactions A, 2001, 32(11): 2759-2768.
[9]Rietveld H M. A profile refinement method for nuclear and magnetic structures[J]. Journal of Applied Crystallography, 1969, 2(2): 65-71.
[10]Xu H F, Zhao J, Cao W Q, et al. Tempering effects on the stability of retained austenite and mechanical properties in a medium manganese steel[J]. ISIJ International, 2012, 52(5): 868-873.
[11]Van Dijk N H, Butt A M, Zhao L, et al. Thermal stability of retained austenite in TRIP steels studied by synchrotron X-ray diffraction during cooling[J]. Acta Materialia, 2005, 53(20): 5439-5447.
[12]张加美. 超低碳中锰钢组织亚微米化机理及强塑性控制[D]. 沈阳: 东北大学, 2018.
[13]Ding R, Dai Z, Huang M, et al. Effect of pre-existed austenite on austenite reversion and mechanical behavior of an Fe-0.2C-8Mn-2Al medium Mn steel[J]. Acta Materialia, 2018, 147: 59-69.
[14]Yang D P, Wu D, Yi H L. Reverse transformation from martensite into austenite in a medium-Mn steel[J]. Scripta Materialia, 2019, 161: 1-5.
[15]Chiang J, Lawrence B, Boyd J D, et al. Effect of microstructure on retained austenite stability and work hardening of TRIP steels[J]. Materials Science and Engineering A, 2011, 528(13/14): 4516-4521.
[16]Lee S J, Kim J, Kane S N, et al. On the origin of dynamic strain aging in twinning-induced plasticity steels[J]. Acta Materialia, 2011, 59(17): 6809-6819.
[17]Cai Z H, Ding H, Misra R D K, et al. Unique serrated flow dependence of critical stress in a hot-rolled Fe-Mn-Al-C steel[J]. Scripta Materialia, 2014, 71: 5-8.
[18]Han J, Lee S J, Jung J G, et al. The effects of the initial martensite microstructure on the microstructure and tensile properties of intercritically annealed Fe-9Mn-0.05C steel[J]. Acta Materialia, 2014, 78: 369-377.
[19]Shi J, Sun X J, Wang M Q, et al. Enhanced work-hardening behavior and mechanical properties in ultrafine-grained steels with large-fractioned metastable austenite[J]. Scripta Materialia, 2010, 63(8): 815-818.
[20]Sugimoto K I, Kobayashi M, Hashimoto S I. Ductility and strain-induced transformation in a high-strength transformation-induced plasticity-aided dual-phase steel[J]. Metallurgical Transactions A, 1992, 23(11): 3085-3091.