Effect of quenching-partitioning process on decomposition of retained austenite in steel during secondary quenching

doi:10.13251/j.issn.0254-6051.2020.10.003

Abstract

Abstract: 0.26C-1.72Si-1.56Mn steel was treated by quenching-partitioning (Q-P) with different carbon partitioning time, and the Q-P microstructure, especially the decomposition of austenite during the secondary quenching stage of the Q-P process, was investigated. The results show that the mix microstructure of lath martensite and secondary quenching microstructure is formed after Q-P treatment, with existence of twin martensite in the secondary quenching microstructure. After Q-P treatment, the C content in retained austenite is higher than 1.0 wt% and the content of retained austenite is not less than 11%(volume fraction) with the partitioning time in the range of 10-300 s, which is beneficial to the improvement of toughness. The morphologies and size of the untransformed austenite after primary quenching are the key factors affecting its stability. The film austenite between primary martensite laths is easy to become retained austenite. Compared with the block untransformed austenite, the strip-shaped untransformed austenite is easy to form secondary quenching martensite and lamellar retained austenite.

Key words: quenching-partitioning, secondary quenching, retained austenite, secondary martensite, twin martensite

CLC Number:

TG156.1

Li Changyun, Zhang Shanshan, Kang Renmu, Xu Lei, Mi Guofa. Effect of quenching-partitioning process on decomposition of retained austenite in steel during secondary quenching[J]. Heat Treatment of Metals, 2020, 45(10): 11-16.

References

[1]Speer J, Matlock D K, Cooman B C D, et al. Carbon partitioning into austenite after martensite transformation[J]. Acta Materialia, 2003, 51(9): 2611-2622.
[2]Zhang K, Zhu M, Lan B, et al. The mechanism of high-strength quenching-partitioning-tempering martensitic steel at elevated temperatures[J]. Crystals, 2019, 9(2): 94-103.
[3]Peng F, Xu Y, Han D T, et al. Influence of pre-tempering treatment on microstructure and mechanical properties in quenching and partitioning steels with ferrite-martensite start structure[J]. Materials Science and Engineering A, 2019, 756: 248-257.
[4]Wang C Y, Li X D, Chang Y, et al. Comparison of three-body impact abrasive wear behaviors for quenching-partitioning-tempering and quenching-tempering 20Si2Ni3 steels[J]. Wear, 2016, 362-363: 121-128.
[5]Qin S W, Liu Y, Hao Q G, et al. High carbon microalloyed martensitic steel with ultrahigh strength-ductility[J]. Materials Science and Engineering A, 2016, 663: 151-156.
[6]Qin S W, Liu Y, Hao Q G, et al. The mechanism of high ductility for novel high-carbon quenching-partitioning-tempering martensitic steel[J]. Metallurgical and Materials Transactions A, 2015, 46(9): 4047-4055.
[7]Zhang K, Liu P, Li W, et al. Ultrahigh strength-ductility steel treated by a novel quenching-partitioning-tempering process[J]. Materials Science and Engineering A, 2014, 619: 205-211.
[8]Li Y J, Liu D, Zhang W N, et al. Quenching above martensite start temperature in quenching and partitioning(Q&P) steel through control of partial phase transformation[J]. Materials Letter, 2018, 230: 36-39.
[9]李娜, 刘国权, 康人木, 等. 一种新型Q-P-T钢的工艺与组织性能[J]. 材料热处理学报, 2013, 34(3): 118-124.
Li Na, Liu Guoquan, Kang Renmu, et al. Processing design and microstructure and mechanical properties of a new type of Q-P-T steel[J]. Transaction of Materials and Heat Treatment, 2013, 34(3): 118-124.
[10]王颖, 张珂, 郭正洪, 等. 残留奥氏体增强低碳Q-P-T钢塑性的新效应[J]. 金属学报, 2012, 48(6): 641-648.
Wang Ying, Zhang Ke, Guo Zhenghong, et al. A new effect of retained austenite on ductility enhancement of low carbon Q-P-T steel[J]. Acta Metallurgica Sinica, 2012, 48(6): 641-648.
[11]Peng F, Xu Y B, Gu X L, et al. The relationships of microstructure-mechanical properties in quenching and partitioning(Q&P) steel accompanied with microalloyed carbide precipitation[J]. Materials Science and Engineering A, 2018, 723: 247-258.
[12]郭浩冉, 高古辉, 桂晓露, 等. 配分温度对Q-P-T 钢组织与性能的影响[J]. 材料热处理学报, 2017, 38(9): 89-95.
Guo Haoran, Gao Guhui, Gui Xiaolu, et al. Effect of partitioning temperature on microstructure and mechanical properties of Q-P-T steel[J]. Transaction of Materials and Heat Treatment, 2017, 38(9): 89-95.
[13]Kang T, Zhao Z Z, Liang J H, et al. Effect of the austenitizing temperature on the microstructure evolution and mechanical properties of Q&P steel[J]. Materials Science and Engineering A, 2020, 771: 138584.
[14]郭艳辉, 付斌, 邓想涛. 低碳硅锰钢的Q＆P 热处理工艺[J]. 金属热处理, 2019, 44(7): 24-27.
Guo Yanhui, Fu Bin, Deng Xiangtao. Q＆P heat treatment process for low carbon Si-Mn steel[J]. Heat Treatment of Metals, 2019, 44(7): 24-27.
[15]Li Y, Chen S, Wang C, et al. Modeling retained austenite in Q&P steels accounting for the bainitic transformation and correction of its mismatch on optimal conditions[J]. Acta Materialia, 2020, 188: 528-538.
[16]Seo E J, Cho L, Estrin Y, et al. Microstructure-mechanical properties relationships for quenching and partitioning(Q&P) processed steel[J]. Acta Materialia, 2016, 113: 124-139.
[17]Seo E J, Cho L, Kim J K, et al. Constituent-specific properties in quenching and partitioning(Q&P) processed steel[J]. Materials Science and Engineering A, 2019, 740-741: 439-444.
[18]Lu J, Yu H, Kang P F, et al. Study of microstructure, mechanical properties and impact-abrasive wear behavior of medium-carbon steel treated by quenching and partitioning(Q&P) process[J]. Wear, 2018, 414-415: 21-30.
[19]Gao G H, Gao B, Gui X L, et al. Correlation between microstructure and yield strength of as-quenched and Q&P steels with different carbon content (0.06-0.42wt%C)[J]. Materials Science and Engineering A, 2019, 753: 1-10.
[20]Parthiban R, Chowdhury S G, Harikumar K C, et al. Evolution of microstructure and its influence on tensile properties in thermo-mechanically controlled processed (TMCP) quench and partition (Q&P) steel[J]. Materials Science and Engineering A, 2017, 705: 376-384.
[21]Allain S Y P, Gaudez S, Geandier G, et al. Carbon heterogeneities in austenite during quenching & partitioning (Q&P) process revealed by in situ high energy X-ray diffraction (HEXRD) experiments[J]. Scripta Materialia, 2020, 181: 108-114.
[22]Sugimoto K I, Tsunezawa M, Hojo T, et al. Ductility of 0.1-0.6C-1.5Si-1.5Mn ultra high-strength TRIP-aided sheet steels with bainitic ferrite matrix[J]. ISIJ International, 2004, 44(9): 1608-1614.
[23]Behera A K, Olson G B. Nonequilibrium thermodynamic modeling of carbon partitioning in quench and partition (Q&P) steel[J]. Scripta Materialia, 2018, 147: 6-10.