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本文以用于成品机架的WC-6%Co(文中含量均为质量分数)硬质合金辊环为研究对象,在其轧制400 T 80A帘线钢线材后,根据轧槽的表面形貌、金相显微组织和裂纹扩展情况对热疲劳裂纹特征进行了分析;结合轧制工况条件,对热疲劳裂纹的形成进行了讨论。分析结果表明:WC-6%Co硬质合金辊环轧槽表面上并未出现明显的龟裂纹,轧槽上的热疲劳裂纹细小且浅;轧制过程中的磨损、氧化、粘结相元素的扩散和冷却水的冲刷等因素的共同作用导致了材料中的WC晶粒的碎化和剥落而形成凹坑;热裂纹在向轧槽内部扩展过程中,以粗大WC晶粒的穿晶断裂为主;辊环材料的高的导热性和断裂韧性能够抑制热疲劳裂纹的萌生和扩展。
In this paper, the WC-6% Co (the content in the text is the mass fraction) hard alloy roll ring for the finished frame is taken as the research object. After rolling 400 T 80A cord steel wire rod according to the surface morphology of the groove, , Microstructure and crack growth of the thermal fatigue crack characteristics were analyzed; combined with rolling conditions, thermal fatigue crack formation were discussed. The results show that there is no obvious crack on the surface of WC-6% Co hard alloy roll ring, the thermal fatigue crack in the groove is small and shallow, and the wear, oxidation and binder phase Elemental diffusion and cooling water scouring and other factors lead to the WC particles in the material fragmentation and spalling and the formation of pits; hot cracks in the rolling groove to the internal expansion process, with coarse WC crystal transgranular Fracture. The high thermal conductivity and fracture toughness of roll ring material can restrain the initiation and propagation of thermal fatigue crack.