Microstructure and strengthening mechanism of 2100 MPa grade ultra-high strength spring steel

doi:10.13251/j.issn.0254-6051.2024.06.024

Abstract

Abstract: Three ultra-high strength steels (1900, 2000 and 2100 MPa) were prepared by optimizing the alloy compositions and quenching and tempering processes. Their microstructure, mechanical properties and strengthening mechanisms were comparatively investigated. The results show that the prior austenite grain size decreases from 28.8 μm to 16.0 μm with the increase of C and V content in the steel. The tensile strength of 2100 MPa grade steel actually reaches 2130 MPa, and the percentage reduction of area is 42%. Further research shows that, the retained austenite in the 2100 MPa grade steel is up to 16.2% in volume fraction, and contributes a transformation-induced plasticity (TRIP) effect during tensile deformation, which significantly improves the work-hardening ability and uniform elongation of the steel. The strength of the 2100 MPa grade spring steel wire mainly comes from solution strengthening, dislocation strengthening and precipitation strengthening, and their contribution values are 391, 808 and 469 MPa, respectively. The fine prior austenite grain size and the TRIP effect from the retained austenite are the key to the excellent strength and ductility of the 2100 MPa grade ultra-high strength spring steel.

Key words: spring steel, microstructure, strength, work hardening, toughness

CLC Number:

TG142.1

Lu Wei, Tu Tianquan, Deng Xiaoyun, Luo Suhui, Xing Xianqiang, Luo Zhichao. Microstructure and strengthening mechanism of 2100 MPa grade ultra-high strength spring steel[J]. Heat Treatment of Metals, 2024, 49(6): 142-149.

References

[1]Wang M, Huang M X. Abnormal TRIP effect on the work hardening behavior of a quenching and partitioning steel at high strain rate[J]. Acta Materialia, 2020, 188: 551-559.
[2]王筱冬. 高强度弹簧钢的发展现状和趋势分析[J]. 中国锰业, 2017, 35(4): 104-106.
Wang Xiaodong. Development status and trend analysis of high strength spring steel[J]. China Manganese Industry, 2017, 35(4): 104-106.
[3]李军, 刘鑫, 曹广祥, 等. 汽车车身高强度钢的应用发展及挑战[J]. 汽车工艺与材料, 2021(8): 1-6.
Li Jun, Liu Xin, Cao Guangxiang, et al. Application development and challenge on high strength steel for automobile body[J]. Automobile Technology and Material, 2021(8): 1-6.
[4]张凯, 陈银莉, 孙彦辉, 等. 加热过程中H₂O(g)对55SiCr弹簧钢脱碳的影响[J]. 金属学报, 2018, 54(10): 1350-1358.
Zhang Kai, Chen Yinli, Sun Yanhui, et al. Effect of H₂O(g) on decarburization of 55SiCr spring steel during the heating process[J]. Acta Metallurgica Sinica, 2018, 54(10): 1350-1358.
[5]马钰, 唐海燕, 刘颜彬, 等. 稀土铈对55SiCr高应力弹簧钢夹杂物的改性作用[J]. 钢铁, 2022, 57(6): 57-71.
Ma Yu, Tang Haiyan, Liu Yanbin, et al. Modification of non-metallic inclusions in 55SiCr high stress spring steel by rare earth Ce[J]. Iron and Steel, 2022, 57(6): 57-71.
[6]邹江河, 姜云. 超高强度弹簧钢冷变形性能及其仿真模拟[J]. 钢铁研究学报, 2020, 32(12): 1157-1164.
Zou Jianghe, Jiang Yun, Cold deformation performance and its simulation of ultra-high strength spring steel[J]. Iron and Steel, 2020, 32(12): 1157-1164.
[7]刘自成, 王学林, 喻异双, 等. 高强度钢韧化机制及与亚结构关系的研究[J]. 钢铁研究学报, 2020, 32(12): 1093-1101.
Liu Zicheng, Wang Xuelin, Yu Yishuang, et al. Study on toughening mechanism of high strength steel and its relationship with substructure[J]. Journal of Iron and Steel Research, 2020, 32(12): 1093-1101.
[8]姜婷, 汪开忠, 于同仁, 等. 热处理工艺对弹簧钢55SiCrV力学性能和组织的影响[J]. 金属热处理, 2019, 44(10): 96-100.
Jiang Ting, Wang Kaizhong, Yu Tongren, et al. Effect of heat treatment process on mechanical properties and microstructure of 55SiCrV spring steel[J]. Heat Treatment of Metals, 2019, 44(10): 96-100.
[9]赵阳磊, 王灵水, 邱胜闻, 等. 60Si2Mn弹簧钢退火过程中的组织与性能变化[J]. 金属热处理, 2021, 46(8): 181-186.
Zhao Yanglei, Wang Lingshui, Qiu Shengwen, et al. Change of microstructure and properties of 60Si2Mn spring steel during annealing[J]. Heat Treatment of Metals, 2021, 26(8): 181-186.
[10]Xia B, Zhang P, Wang B, et al. A simultaneous improvement of the strength and plasticity of spring steels by replacing Mo with Si[J]. Materials Science and Engineering A, 2021, 820: 141516.
[11]Wang J J, Cao Y L, Xiang H J, et al. A piezoelectric smart backing ring for high-performance power generation subject to train induced steel-spring fulcrum forces[J]. Energy Conversion and Management, 2022, 257: 115442.
[12]Xiao G Z, Di H S. Delayed fracture resistance and mechanical properties of 30MnSi high strength steel[J]. Journal of lron and Steel Research, 2009, 16(3): 49-54.
[13]刘延强, 王丽君, 胡晓军, 等. 国内外超低氧弹簧钢生产工艺比较[J]. 钢铁研究学报, 2012, 24(12): 1-5.
Liu Yanqiang, Wang Lijun, Hu Xiaojun, et al. Comparison of processing techniques used in ultra-low oxygen spring steel production both domestic and abroad[J]. Journal of Iron and Steel Research, 2012, 24(12): 1-5.
[14]赵东宇, 雍岐龙, 杨庚蔚, 等. 铌对60Si2Mn弹簧钢表面脱碳敏感性的影响[J]. 钢铁, 2014, 49(5): 74-80.
Zhao Dongyu, Yong Qilong, Yang Gengwei, et al. Effect of niobium on surface decarburization sensitivity of 60Si2Mn spring steel[J]. Iron and Steel, 2014, 49(5): 74-80.
[15]刘耀中, 左传付. 轴承钢零件淬回火后的残留奥氏体[J]. 轴承, 2008(6): 48-51.
Liu Yaozhong, Zuo Chuanfu. The retained austenite in bearing steel after quenching and tempering[J]. Bear, 2008(6): 48-51
[16]Liang J, Lu H, Zhang L, et al. A 2000 MPa grade Nb bearing hot stamping steel with ultra-high yield strength[J]. Materials Science and Engineering A, 2021, 801: 140419.
[17]陈继平, 张乐, 邢献强, 等. 氧化时间对低合金弹簧钢奥氏体晶粒度测定的影响[J]. 金属热处理, 2021, 46(8): 241-245.
Chen Jiping, Zhang Le, Xing Xianqiang, et al. Effect of oxidation time on evaluation of austenite grain size of low alloy spring steel[J]. Heat Treatment of Metals, 2021, 46(8): 241-245.
[18]苏德达. 弹簧(材料)应力松弛及预防[M]. 天津: 天津大学出版社, 2002.
[19]Luo Z F, Jiang Y, Wu Z, et al. Effects of ultra-refine grain and micro-nano twins on mechanical properties of 51CrV4 spring steel[J]. Materials Science, 2017, 690: 225-232.
[20]文凤, 陈永利, 周雪娇, 等. 循环淬火对B/M超高强钢奥氏体晶粒细化的影响[J]. 热加工工艺, 2017(8): 196-198.
Wen Feng, Chen Yongli, Zhou Xuejiao, et al. Influences of cycle quenching on austenite grain refinement of B/M ultra-high strength steel[J]. Hot Working Technology, 2017(8): 196-198.
[21]Chen W J, Gao P F, Wang S, et al. Strengthening mechanisms of Nb and V microalloying high strength hot-stamped steel[J]. Materials Science and Engineering A, 2020, 797: 140115.
[22]Kim A B, Boucard B E, Sourmail C T, et al. The influence of silicon in tempered martensite: Understanding the microstructure-properties relationship in 0.5-0.6wt.%C steels[J]. Acta Materialia. 2014, 68(15): 169-178.
[23]李东辉, 李志敏, 肖茂果,等. 深冷处理对低碳高合金马氏体轴承钢力学性能及组织的影响[J]. 材料研究学报, 2019, 33(8): 561-571.
Li Donghui, Li Zhimin, Xiao Maoguo, et al. Effect of cryogenic treatment on mechanical properties and microstructure of low carbon high alloy martensitic bearing steel[J]. Journal of Materials Research, 2019, 33(8): 561-571.