Effect of solution treatment on microstructure and properties of Cr23Ni7Mo2Cu0.6 duplex stainless steel

doi:10.13251/j.issn.0254-6051.2022.06.010

Abstract

Abstract: Effect of solution treatment on microstructure and properties of Cr23Ni7Mo2Cu0.6 duplex stainless steel was studied by XSL-4-12 box heat treatment furnace, Zeiss metallographic microscope, HRS-150 digital Rockwell hardness tester and tensile test machine. The results show that the content of ferrite increases with the increase of solution temperature, and the area ratio of ferrite to austenite reaches 1∶1 between 930 ℃ and 960 ℃. The content of σ phase decreases with the increase of solution temperature, only a small amount of σ phase exists at phase boundary at 960 ℃, and the uneven distribution of austenite phase due to forging at 1020 ℃ is also improved. The hardness and tensile strength of the alloy decrease at first and then increase with the increase of solution temperature, reaching the minimum values of 94.4 HRB at 1020 ℃ and 547 MPa at 1050 ℃, respectively. The elongation increases at first and then decreases with the increase of solution temperature, reaching a peak value of 41.5% at 990 ℃. Considering the effects of hardness, plasticity, toughness and microstructure uniformity of the material on formability of the material during drawing and deformation of the steel wire, the optimal solution temperature of the Cr23Ni7Mo2Cu0.6 duplex stainless steel is 1020 ℃.

Key words: Cr23Ni7Mo2Cu0.6 duplex stainless steel, solution treatment, σ phase, microstructure, properties

CLC Number:

TG156.94

Chen Jiajun, Zhu Zhiyuan, Li Jianqiang, Wang Shouqian. Effect of solution treatment on microstructure and properties of Cr23Ni7Mo2Cu0.6 duplex stainless steel[J]. Heat Treatment of Metals, 2022, 47(6): 59-63.

References

[1]Parayil T R, Howell P R. Decomposition of deformed ferrite in a duplex stainless steel[J]. Material Science and Technology, 1986, 2(11): 1131-1139.
[2]Peick W, Pohl M, Padilha A F. Recrystallization-transformation combined reactions during annealing of a cold rolled ferritic-austenitic duplex stainless steel[J]. ISIJ International, 1998, 38(6): 567-571.
[3]Lo K H, Shek C H, Lai J K L. Recent developments in stainless steels[J]. Materials Science and Engineering R-Reports, 2009, 65(4-6): 39-104.
[4]Maehara Y, Koike M, Fujino N, et al. Precipitation of σ phase in a 25Cr-7Ni-3Mo duplex phase stainless steel[J]. Transactions of the Iron and Steel Institute of Japan, 1983, 23(3): 240-246.
[5]Han Y, Zou D N, Zhang W, et al. Sigma phase precipitation of duplex stainless steel and its effect on corrosion resistance[J]. Materials Science Forum, 2009, 620-622: 391-394.
[6]刘燕, 高仁强, 陈兴润, 等. 2205双相不锈钢中σ相析出的影响因素分析[J]. 金属热处理, 2021, 46(3): 180-183.
Liu Yan, Gao Renqiang, Chen Xingrun, et al. Analysis of influencing factors of σ phase precipitation in 2205 duplex stainless steel[J]. Heat Treatment of Metals, 2021, 46(3): 180-183.
[7]高晓丹, 任学平, 李晶琨, 等. 时效工艺对2205双相不锈钢σ相析出行为的影响[J]. 金属热处理, 2020, 45(10): 1-5.
Gao Xiaodan, Ren Xueping, Li Jingkun, et al. Effect of aging process on σ phase precipitation of 2205 duplex stainless steel[J]. Heat Treatment of Metals, 2020, 45(10): 1-5.
[8]王小勇, 黄乐庆, 王海宝, 等. 固溶处理对双相不锈钢组织与性能的影响[J]. 金属热处理, 2018, 43(5): 101-105.
Wang Xiaoyong, Huang Leqing, Wang Haibao, et al. Influence of solution treatment on microstructure and properties of duplex stainless steel[J]. Heat Treatment of Metals, 2018, 43(5): 101-105.
[9]Shek C H, Wong K W, Lai J K L, et al. Hot tensile properties of 25Cr-8Ni duplex stainless steel containing cellular (σ+γ₂) structure after various thermal treatments[J]. Materials Science and Engineering A, 1997, 231(1/2): 42-47.
[10]Shek C H, Li D J, Wong K W, et al. Creep properties of aged duplex stainless steels containing σ phase[J]. Materials Science and Engineering A, 1999, 266(1/2): 30-36.
[11]Wang Y Q, Han J, Wu H C, et al. Effect of sigma phase precipitation on the mechanical and wear properties of Z3CN20.09M cast duplex stainless steel[J]. Nuclear Engineering and Design, 2013, 259: 1-7.
[12]Badji R, Bouabdallah M, Bacroix B, et al. Phase transformation and mechanical behavior in annealed 2205 duplex stainless steel welds[J]. Materials Characterization, 2008, 59(4): 447-453.
[13]Moayed M H, Laycock N J, Newman R C. Dependence of the critical pitting temperature on surface roughness[J]. Corrosion Science, 2003, 45(6): 1203-1216.
[14]Sieurin H, Sandström R. Austenite reformation in the heat-affected zone of duplex stainless steel 2205[J]. Materials Science and Engineering A, 2006, 418(1/2): 250-256.
[15]Gideon B, Ward L, Biddle G. Duplex stainless steel welds and their susceptibility to intergranular corrosion[J]. Journal of Minerals and Materials Characterization and Engineering, 2008, 7(3): 247-263.
[16]Liou H Y, Hsieh R H, Tsai W T. Microstructure and pitting corrosion in simulated heat-affected zones of duplex stainless[J]. Materials Chemistry and Physics, 2002, 74(1): 33-42.
[17]Chen T H, Yang J R. Microstructural characterization of simulated heat affected zone in a nitrogen-containing 2205 duplex stainless steel[J]. Materials Science and Engineering A, 2002, 338(1/2): 166-181.