超高强度帘线钢LX92A连续和等温冷却下的相变行为

doi:10.13251/j.issn.0254-6051.2021.05.005

摘要/Abstract

摘要： 通过热模拟试验研究了超高强度帘线钢LX92A在920 ℃压缩变形60%后的动态连续冷却转变和等温转变行为。连续冷却转变时,当冷速为0.5 K/s及以下时,在晶界位置存在明显网状结构渗碳体;当冷速达到1 K/s及以上时,渗碳体变为线条状,并随冷速增大,渗碳体逐渐减少;当冷速达到15 K/s以上时,组织中出现马氏体。等温转变时,珠光体转变的温度区间为550~700 ℃,鼻尖温度约为604 ℃,随温度降低,转变后的显微组织由粗大片层状珠光体向片状珠光体、索氏体、屈氏体转变,当转变温度降低到525 ℃时,组织中出现贝氏体。研究了珠光体片层间距与过冷度和冷速的关系,并采用回归分析法得到了片层间距模型,拟合优度分别达到0.99和0.97以上。

关键词: 超高强度帘线钢, 连续冷却, 等温转变, 珠光体, 片层间距

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

中图分类号:

TG142.1

李战卫, 沈奎, 于学森, 张宇. 超高强度帘线钢LX92A连续和等温冷却下的相变行为[J]. 金属热处理, 2021, 46(5): 32-37.

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.

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