Effect of different intercritical quenching temperature on microstructure and properties of 9Ni Steel

doi:10.13251/j.issn.0254-6051.2021.07.004

Abstract

Abstract: Effects of different intercritical quenching temperatures in the range of 620-680 ℃ on the strength and low temperature impact property of 9Ni steel were analyzed by means of SEM, XRD, fatigue testing machine, and impact testing machine. The results show that the content and stability of reversed austenite have a significant effect on the material properties. With the increase of intercritical quenching temperature, the tensile strength of the steel continues to increase, while the low temperature impact property presents a nonlinear trend of first increasing and then decreasing. When the intercritical quenching temperature is 640 ℃, the reversed austenite content, the elongation after fracture, the impact absorbed energy of the specimens all are the highest, respectively being 9.65%, 32.67%, 332.83 J at room temperature and 297.69 J at -196 ℃, showing the best match of strength and toughness on the whole.

Key words: 9Ni steel, intercritical quenching temperature, microstructure, reversed austenite, mechanical properties

CLC Number:

TG142.79

Li Rongbin, Qin Pinqiang, Chen Yongqiang, Li Ke, Long Wenyong. Effect of different intercritical quenching temperature on microstructure and properties of 9Ni Steel[J]. Heat Treatment of Metals, 2021, 46(7): 18-22.

References

[1] 杨跃辉, 蔡庆伍, 武会宾, 等. 两相区热处理过程中回转奥氏体的形成规律及其对9Ni钢低温韧性的影响[J]. 金属学报, 2009, 45(3): 270-274.
Yang Yuehui, Cai Qingwu, Wu Huibin, et al. Formation of reversed austenite and its effect on cryogenic toughness of 9Ni steel during two-phase region heat treatment[J]. Acta Metallurgica Sinica, 2009, 45(3): 270-274.
[2] 郭魁文, 朱健, 王秉新. 两相区热处理对9Ni钢低温韧性的影响[J]. 辽宁石油化工大学学报, 2010, 30(2): 26-28.
Guo Huaiwen, Zhu Jian, Wang Bingxin. Influence of two-phase region heat treatment on cryogenic toughness in 9Ni steel[J]. Journal of Liaoning Petrochemical University, 2010, 30(2): 26-28.
[3] Kinney C C, Pytlewski K R, Khachaturyan A G, et al. The microstructure of lath martensite in quenched 9Ni steel[J]. Acta Materialia, 2014, 69: 372-385
[4] 杨跃辉, 苑少强, 刘坚, 等. 快速加热回火过程中9Ni钢组织的演化[J]. 材料热处理学报, 2019, 40(6): 97-102.
Yang Yuehui, Yuan Shaoqiang, Liu Jian, et al. Microstructure evolution of 9Ni steel during rapid heating and tempering[J]. Transactions of Materials and Heat Treatment, 2019, 40(6): 97-102.
[5] Nakanishi D, Kawabata T, Aihara S. Effect of dispersed retained γ-Fe on brittle crack arrest toughness in 9% Ni steel in cryogenic temperatures[J]. Materials Science and Engineering A, 2018, 723: 238-246.
[6] 谢章龙, 刘振宇, 陈俊, 等. 9Ni钢薄板的奥氏体化温度及强韧化因素分析[J]. 钢铁研究学报, 2011, 23(9): 37-38.
Xie Zhanglong, Liu Zhenyu, Chen Jun, et al. Austenitizing temperature for 9Ni steel thin plate and analysis of strengthening and toughening factors[J]. Journal of Iron and Steel Research, 2011, 23(9): 37-38.
[7] 曹宏玮, 罗兴宏, 刘实. 淬火温度对7Ni钢低温力学性能的影响[J]. 材料研究学报, 2018, 32(5): 388-394.
Cao Hongwei, Luo Xinghong, Liu Shi. Effect of quenching temperature on cryogenic mechanical properties of a 7Ni steel[J]. Chinese Journal of Materials Research, 2018, 32(5): 388-394.
[8] 许立雄, 武会宾, 牟丹. 两相区淬火对7Ni钢微观组织和力学性能的影响[J]. 材料工程, 2018, 46(8): 113-119.
Xu Lixiong, Wu Huibin, Mou Dan. Effect of quenching in dual-phase region on microstructure and mechanical properties of 7Ni steel[J]. Journal of Materials Engineering, 2018, 46(8): 113-119.
[9] 赵宏禹, 刘荣佩, 王长军, 等. QLT与QT热处理工艺对9Ni低温钢性能的影响[J]. 金属热处理, 2018, 43(12): 100-104.
Zhao Hongyu, Liu Rongpei, Wang Changjun, et al. Influence of QLT and QT heat treatment process on properties of 9Ni steel[J]. Heat Treatment of Metals, 2018, 43(12): 100-104.
[10] Cheng J H, Shen J C, He Y Z, et al. Effect of quenching lamellarizing and tempering process on strength and toughness of 9NiCrMo steel[J]. Iron and Steel, 2014, 49(9): 87-91.
[11] Jang J, Ju J B, Lee B W, et al. Effects of microstructural change on fracture characteristics in coarse-grained heat-affected zones of QLT processed 9%Ni steel[J]. Materials Science and Engineering A, 2003, 340(1): 68-79.
[12] Zhang J M, Li H, Yang F, et al. Effect of heat treatment process on mechanical properties and microstructure of a 9% Ni steel for large LNG storage tanks[J]. Journal of Materials Engineering and Performance, 2013, 22(12): 3867-3871.
[13] 刘文斌, 战国锋, 黄峰. 回火温度对7Ni钢组织和性能的影响[J]. 金属热处理, 2020, 45(12): 63-68.
Liu Wenbin, Zhan Guofeng, Huang Feng. Effect of tempering temperature on microstructure and properties of 7Ni steel[J]. Heat Treatment of Metals, 2020, 45(12): 63-68.
[14] Yang Y H, Cai Q W, Wu H B. Formation of reversed austenite and its effect on cryogenic toughness of 9Ni steel during two-phase region heat treatment[J]. Acta Metallurgica Sinica, 2009, 45(3): 270-274.
[15] Yang Y H, Cai Q W, Tang D, et al. Precipitation and stability of reversed austenite in 9Ni steel[J]. International Journal of Minerals Metallurgy and Materials, 2010, 17(5): 587-595.
[16] 张坤, 唐荻, 武会宾. 逆转变奥氏体对9Ni钢低温冲击韧度的影响[J]. 热加工工艺, 2012, 41(8): 177-179.
Zhang Kun, Tang Di, Wu Huibin. Effect of reversed austenite on impact toughness of 9Ni steel at low temperature[J]. Hot Working Technology, 2012, 41(8): 177-179.