Microstructure evolution and mechanical properties of bearing steel for tunnel boring machine during hot rolling and spheroidizing annealing process

doi:10.13251/j.issn.0254-6051.2025.05.002

Abstract

Abstract: Effect of rapid cooling process after rolling(final cooling temperature) on microstructure evolution and mechanical properties of the tested bearing steel during hot rolling and spheroidizing annealing was systematically studied by means of Gleeble-3500 thermal simulator, OM, SEM, EBSD, tensile test and hardness test. The results show that when the final cooling temperature decreases from 650 ℃ to 570 ℃, the pearlite lamellar spacing decreases from 109.87 nm to 68.77 nm, and the yield strength and tensile strength increase from 899 MPa and 1127 MPa to 1333 MPa and 1655 MPa, respectively. After isothermal spheroidizing annealing, the spheroidization rate of cementite is more than 85%, and the hardness of the tested steel is between 230 HV0.5 and 240 HV0.5. As the pearlite lamellar spacing increases, the size of carbide particles and ferrite grains gradually decreases after spheroidizing annealing, and the hardness of the microstructure gradually increases. After comprehensive comparison of the microstructure and mechanical properties after hot rolling and spheroidizing annealing, the pearlite lamellar spacing of the specimen with a final cooling temperature of 570 ℃ is the smallest, the spheroidization rate of the cementite is the highest after spheroidizing annealing, the hardness is relatively low, and the processing property is better.

Key words: bearing steel, tunnel boring machine, final cooling temperature, spheroidizing annealing, microstructure, mechanical properties

CLC Number:

TG335.1

Tong Shankang, Wang Wei, Gan Xiaolong, Xue Zhengliang, Tian Hao, Li Desheng, Xu Guang. Microstructure evolution and mechanical properties of bearing steel for tunnel boring machine during hot rolling and spheroidizing annealing process[J]. Heat Treatment of Metals, 2025, 50(5): 9-15.

References

[1] 刘雅政, 黄斌, 蒋波, 等. 盾构机轴承用钢的开发与质量控制[J]. 钢铁, 2014, 49(5): 1-6, 12.
Liu Yazheng, Huang Bin, Jiang Bo, et al. Development and quality control of bearing steel for tunnel shield machine[J]. Iron and Steel, 2014, 49(5): 1-6, 12.
[2] Liu Y Z, Fan C H. Development and prospect of heat treatment technology for rolling bearing parts made of high carbon chromium bearing steel[J]. Heat Treatment of Metals, 2014, 39(1): 53-57.
[3] 张丹. 盾构机用大断面高碳铬轴承钢组织性能控制研究[D]. 北京: 北京科技大学, 2015.
[4] Brien J M O, Hosford W F. Spheroidization cycles for medium carbon steels[J]. Metallurgical and Materials Transactions A, 2002, 33: 1255-1261.
[5] Li Z X, Li C S, Zhang J, et al. Effects of annealing on carbides size and distribution and cold formability of 1.0C-1.5Cr bearing steel[J]. Metallurgical and Materials Transactions A, 2015, 46: 3220-3231.
[6] Bhadeshia H K D H. Steels for bearings[J]. Progress in Materials Science, 2012, 57(2): 268-435.
[7] Li Z X, Li C S, Ren J Y, et al. Design of online spheroidization process for 1.0C-1.5Cr bearing steel and microstructure analysis[J]. Metallurgical and Materials Transactions A, 2018, 49: 1782-1794.
[8] Wang W, Luo T, Liu Z, et al. Influences of cooling rate on solidification microstructure and carbide of GCr15 bearing steel[J]. Metallurgical and Materials Transactions B, 2023, 54(2): 776-792.
[9] Mao M, Guo H, Wang F, et al. Effect of cooling rate on the solidification microstructure and characteristics of primary carbides in H13 steel[J]. ISIJ International, 2019, 59(5): 848-857.
[10] Jiang D, Zhang L. Influence of cooling parameters on the microstructure and primary carbide precipitation in GCr15 steel[J]. Steel Research International, 2021, 92(11): 1-9.
[11] Huo X, Ning Y, Li L, et al. Research and control of network carbide in GCr15 bearing steel[J]. Materials Research Express, 2020, 7: 016559.
[12] Li Z X, Li C S, Zhang J, et al. Microstructure of hot rolled 1.0C-1.5Cr bearing steel and subsequent spheroidization annealing[J]. Metallurgical and Materials Transactions A, 2016, 47: 3607-3621.
[13] Wang M, Zhang F, Yang Z. Effects of high-temperature deformation and cooling process on the microstructure and mechanical properties of an ultrahigh-strength pearlite steel[J]. Materials and Design, 2017, 114: 102-110.
[14] 李振兴. GCr15轴承钢热加工及热处理过程的组织与性能研究[D]. 沈阳: 东北大学, 2018.
[15] Shanmugam S, Misra R D K, Mannering T, et al. Impact toughness and microstructure relationship in niobium-and vanadium microalloyed steels processed with varied cooling rates to similar yield strength[J]. Materials Science and Engineering A, 2006, 437(2): 436-445.
[16] Seo S W, Bhadeshia H, Suh D W. Pearlite growth rate in Fe-C and Fe-Mn-C steels[J]. Materials Science and Technology, 2015, 31(4): 487-493.
[17] Sun Y, Wu D. Effect of ultra-fast cooling on microstructure of large section bars of bearing steel[J]. Journal of Iron and Steel Research International, 2009, 16(5): 61-65.
[18] 孙艳坤. 轴承钢热变形及冷却过程中珠光体相变研究[J]. 热加工工艺, 2011, 40(20): 157-159.
Sun Yankun. Research on pearlite transformation in hot-reforming and cooling process for bearing steel[J]. Hot Working Technology, 2011, 40(20): 157-159.
[19] 梁宇, 余凌锋, 梁益龙. 珠光体钢微观组织与拉伸性能关系[J]. 材料热处理学报, 2013, 34(7): 73-77.
Liang Yu, Yu Lingfeng, Liang Yilong. Relationship between microstructure and tensile properties of a pearlitic steel[J]. Transactions of Materials and Heat Treatment, 2013, 34(7): 73-77.
[20] Elwazri A M, Wanjara P, Yue S. The effect of microstructural characteristics of pearlite on the mechanical properties of hypereutectoid steel[J]. Materials Science and Engineering A, 2005, 404(1/2): 91-98.
[21] Gang U G, Lee J C, Nam W J. Effect of prior microstructures on the behavior of cementite particles during subcritical annealing of medium carbon steels[J]. Metals and Materials International, 2009, 15: 719-725.
[22] Qi M, Wu H, Zhang Z M. Subcritical spheroidization annealing of cold rolled Cr-Mo microalloyed medium carbon steel with different initial microstructure[J]. Steel Research International, 2023, 94(5): 7-11.
[23] Zhao X, Zhao X, Dong C, et al. Effect of prior microstructures on cementite dissolution behavior during subcritical annealing of high carbon steels[J]. Metals and Materials International, 2021, 28(6): 1-13.
[24] Li Z X, Li C S, Kim S H, et al. Influence of initial pearlite morphology on the microstructure evolution during heat treatment of 1.0C-1.5Cr steel[J]. Metals and Materials International, 2018, 25: 9-17.
[25] Zhang H, Pradeep K G, Mandal S, et al. Enhanced superplasticity in an Al-alloyed multicomponent Mn-Si-Cr-C steel[J]. Acta Materialia, 2014, 63: 232-244.
[26] Prasad C, Bhuyan P, Kaithwas C, et al. Microstructure engineering by dispersing nano-spheroid cementite in ultrafine grained ferrite and its implications on strength-ductility relationship in high carbon steel[J]. Materials and Design, 2018, 139: 324-335.
[27] Storojeva L, Ponge D, Kaspar R, et al. Development of microstructure and texture of medium carbon steel during heavy warm deformation[J]. Acta Materialia, 2004, 52(8): 2209-2220.
[28] Li L F, Wang Y. Microstructure evolution of a pearlitic steel during hot deformation of undercooled austenite and subsequent annealing[J]. Metallurgical and Materials Transactions A, 2008, 39(3): 624-635.