Phase transformation behaviors of ultra high strength cord steel LX92A in continuous cooling and isothermal cooling

doi:10.13251/j.issn.0254-6051.2021.05.005

Abstract

Abstract: The transformation behaviors of ultra high strength cord steel LX92A in continuous cooling and isothermal cooling after compressively deforming of 60% at 920 ℃ were studied by thermal simulation. The results show that the cooling rates of 0.5 K/s and below in continuous cooling produce network cementite at grain boundaries. When cooling rate reaches 1 K/s or above, the cementite becomes line-shaped and its quantity decreases with the increase of cooling rate; and when the cooling rate increases above 15 K/s, martensitic transformation occurs. For the isothermal cooling, the temperature range of pearlitic transformation is 550-700 ℃, and the nose tip temperature is about 604 ℃. With the decrease of isothermal transformation temperature, the microstructure changes from coarse lamellar pearlite to lamellar pearlite, fine lamellar pearlite, till bainite appears at 525 ℃. Predictive models of pearlite lamellar spacing based on the degree of undercooling and cooling rate are obtained by regression analysis, with their fitness factors reach above 0.99 and 0.97, respectively.

Key words: ultra high strength cord steel, continuous cooling, isothermal transformation, pearlite, interlamellar spacing

CLC Number:

TG142.1

Li Zhanwei, Shen Kui, Yu Xuesen, Zhang Yu. Phase transformation behaviors of ultra high strength cord steel LX92A in continuous cooling and isothermal cooling[J]. Heat Treatment of Metals, 2021, 46(5): 32-37.

References

[1]顾元国. 汽车用高强帘线钢92A的二火开坯工艺研究[J]. 热加工工艺, 2018, 47(7): 108-111.
Gu Yuanguo. Study on rerolling process of high strength cord steel 92A for automobile[J]. Hot Working Technology, 2018, 47(7): 108-111.
[2]姚利丽, 朱晨露, 华欣, 等. 国内外超高强度钢帘线用盘条微观组织研究[J]. 金属制品, 2016, 42(6): 41-47.
Yao Lili, Zhu Chenlu, Hua Xin, et al. Study on microstructure of domestic and imported wire rods for ultra high strength steel cord[J]. Metal Products, 2016, 42(6): 41-47.
[3]王培滨, 刘红锁, 张世鑫, 等. ST/UT超高强度钢丝帘线在子午线轮胎中的应用[J]. 轮胎工业, 2018, 38(5): 296-301.
Wang Peibin, Liu Hongsuo, Zhang Shixin, et al. Application of ultra high strength steel cord in radial tire[J]. Tire Industry, 2018, 38(5): 296-301.
[4]Hitoshi Tashiro, Toshimi Tarui. State of the art for high tensile strength steel cord[J]. Nippon Steel Technical Report, 2003, 88(7): 87-91.
[5]余万华, 刘飞, 高山, 等. 超高强度帘线钢C92DA的连续冷却特性[J]. 材料热处理学报, 2014, 35(12): 150-154.
Yu Wanhua, Liu Fei, Gao Shan, et al. Continuous cooling characteristics of ultra-high-strength steel C92DA for tyre core wire[J]. Transactions of Materials and Heat Treatment, 2014, 35(12): 150-154.
[6]崔忠圻, 覃耀春. 金属学与热处理[M]. 北京: 机械工业出版社, 2007: 243.
[7]彭红兵, 唐尧. 国内外帘线用高碳钢线材质量对比[J]. 金属热处理, 2019, 44(12): 44-48.
Peng Hongbing, Tang Yao. Quality comparison of the high carbon steel for domestic and foreign cord wire application[J]. Heat Treatment of Metals, 2019, 44(12): 44-48.
[8]王伯文. 高碳钢线材轧后冷却工艺优化[D]. 武汉: 武汉科技大学, 2009.
Wang Bowen. Cooling technology improvement of high-carbon steel wire after rolling[D]. Wuhan: Wuhan University of Science and Technology, 2009.
[9]李月云, 胡磊, 王雷, 等. 高性能预应力钢绞线盘条SWRH72BCr-1的开发[J]. 金属热处理, 2018, 43(9): 31-36.
Li Yueyun, Hu Lei, Wang Lei, et al. Development of high performance prestressed steel strand wire SWRH72BCr-1[J]. Heat Treatment of Metals, 2018, 43(9): 31-36.
[10]王国红, 宗斌, 魏建忠. 碳钢盘条中珠光体类型组织的区分和判定[J]. 冶金标准化与质量, 2005, 43(4): 13-16.
Wang Guohong, Zong Bin, Wei Jianzhong. Differentiation and identification of the pearlite structure types in carbon steel wire rod[J]. Metallurgical Standardization and Quality, 2005, 43(4): 13-16.
[11]Han K, Edmonds D V, Smith G D W. Optimization of mechanical properties of high-carbon pearlitic steels with Si and V additions[J]. Metallurgical and Materials Transactions A, 2001, 32(6): 1313-1324.
[12]江卓俊, 沈奎, 于学森, 等. 控冷工艺对帘线钢盘条组织及性能的影响[J]. 热加工工艺, 2019, 48(13): 124-126, 130.
Jiang Zhuojun, Shen Kui, Yu Xuesen, et al. Effect of controlled cooling technology on microstructure and properties of cord steel wires[J]. Hot Working Technology, 2019, 48(13): 124-126, 130.
[13]Elwazri A M, Wanjara P, Yue S. Empirical modelling of the isothermal transformation of pearlite in hypereutectoid steel[J]. Materials Science and Technology, 2006, 22(5): 542-546.
[14]魏勇, 韦贺, 严海峰, 等. 等温温度对82B高碳钢过冷奥氏体转变的影响[J]. 金属热处理, 2018, 43(12): 211-215.
Wei Yong, Wei He, Yan Haifeng, et al. Effect of isothermal temperature on undercooled austenite transformation of 82B high carbon steel[J]. Heat Treatment of Metals, 2018, 43(12): 211-215.
[15]笪光杰, 杨忠民, 王凯, 等. 奥氏体化温度和冷却速率对含Nb高碳钢组织性能的影响[J]. 金属热处理, 2020, 45(6): 1-6.
Da Guangjie, Yang Zhongmin, Wang Kai, et al. Effects of austenitizing temperature and cooling rate on microstructure and properties of Nb-containing high carbon steel[J]. Heat Treatment of Metals, 2020, 45(6): 1-6.
[16]Zener C. Kinetic of the decomposition of austenite[J]. Transactions of the American Institute of Mining and Metallurgical Engineers, 1946, 167: 550-595.
[17]Hillert M. Solid state phase transformation[J]. Jenkontorets Annaler, 1957, 141: 757-790.
[18]卫广智, 潘广明, 齐福利. SWRH82B珠光体片层间距计算模型研究[J]. 现代机械, 2012(1): 72-73, 88.
Wei Guangzhi, Pan Guangming, Qi Fuli. Research on the calculation models of interlamellar spacing of pearlite in SWRH82B steel[J]. Modern Machinery, 2012(1): 72-73, 88.
[19]Kumar A, McCulloch C, Hawbolt E B, et al. Modelling thermal and microstructural evolution on runout table of hot strip mill[J]. Material Science and Technology, 1991, 7(4): 360-368.