高速钢复合轧辊表面大面积剥落的原因

Cause of Large Area Spalling on Surface of High Speed Steel Composite Roll

通过化学成分分析、力学性能检测、显微组织和断口形貌观察等方法,对高速钢复合轧辊表面大面积剥落的原因进行了分析。结果表明:三次浇注工艺控制不当及心部球墨铸铁液纯净度不够导致复合轧辊中间层与高速钢表层及心部铸铁层的界面处存在大量粗大碳化物、片状分布的疏松孔洞以及聚集分布的夹杂物带等严重缺陷,使得界面处的结合不良;在轧制力的作用下,裂纹在上述缺陷处萌生,并沿缺陷处快速扩展,最后导致轧辊表面发生大面积剥落失效。

The reason for large area spalling on the surface of high speed steel composite roll was analyzed by chemical composition analysis,mechanical property testing,microstucture and fracture morphology observation.The results show that the improper control process of three time pouring and low purity of core ductile iron liquid led to the generation of a large number of serious defects such as the coarse carbides,loose pore defects distributed in sheets and inclusions distributed aggregatively at the interface between the middle layer and the high speed steel surface layer and the core cast iron layer of the composite roll,resulting in poor bonding at the interface.Under rolling force,the crack initiated at the these defects and rapidly expanded along the defects,ultimately leading to large area spalling failure on the surface of the roll.