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冷轧辊断裂原因分析上钢三厂钢研所金相组冷轧辊要求高的表面光洁度。一般使用6～7小时要磨削一次。质量好的冷轧辊使用寿命可达200多次的磨削周期,而质量差的却只有30～40次的磨削周期就断裂。经过对断辊的断口分析,发现裂纹起源于中心孔的刀痕,然后向外扩展,最后导致瞬时断裂。断口的微观形貌是解理或准解理,在解理面交界处有一层韧窝。金相检验看到轧辊中心区域的组织是粗片状珠光体和呈偏析分布的碳化物。而长寿命的轧辊中心区域是球化组织。作者认为,轧辊中心孔加工粗糙是形成裂纹的外因,而锻压和热处理工艺不当,形成碳化物偏析和片状珠光体是使裂纹不受干扰地扩展的内因。因此某些工厂规定辊身基体组织的球化率要大于70％。
Analysis of the reasons for the fracture of the cold roll The high temperature surface finish required by the cold roll of the metallographic group of the Steel Research Institute of No.3 Steel Works. The general use of 6 to 7 hours to be ground once. Good quality cold roll life of up to 200 times the grinding cycle, while poor quality but only 30 to 40 times the grinding cycle rupture. After analysis of the fracture of the broken roller, it was found that the crack originated in the center hole and then expanded outward, finally leading to instantaneous fracture. Fracture micro-morphology is cleavage or quasi-cleavage, cleavage at the junction of a layer of dimples. Metallographic examination to see the roll center of the organization is coarse pearlite and segregation distribution of carbides. The long-life roller center area is spheroidization organization. The author believes that the rough machining of the center hole of the roll is the external cause of the crack formation, while the forging and heat treatment process is improper. The formation of carbide segregation and lamellar pearlite is the internal cause of expanding the crack without interference. Therefore, some factories require that the nodularity of the barrel body should be greater than 70%.