摘要
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。
The thermal fatigue crack characteristics of the WC-6%Co carbide roll used in reducing sizing stands,after rolling 400 tons 80A grade of tyre cord steel wire rod,were analyzed according to groove surface morphology,metallurgical microstructure and crack propagation.The forming process of the thermal fatigue crack was discussed combining with the operating conditions.The results show that the turtle cracks do not appear in the groove surface obviously,the thermal fatigue cracks are fine and shallow.In the rolling process,such factors as wear,oxidization,diffusion of binder phase elements and scouring of cooling water,result in the fragmentizing and spalling of WC grains and form the pits.In the propagation process towards the groove interior,thermal cracks are mainly the transgranular fractures on the coarse WC grains.The high thermal conductivity and fracture toughness of the carbide roll material can inhibit thermal fatigue crack initiation and propagation.
出处
《硬质合金》
CAS
北大核心
2011年第2期73-77,共5页
Cemented Carbides
