中文摘要：

用断口形貌、化学成分、显微组织及力学性能测试等对21CrMo V5.11钢连铸辊早期断裂进行分析。结果表明,连铸辊的断裂属于疲劳断裂。疲劳源为堆焊层表面由于堆焊工艺控制不当而产生的周向裂纹;堆焊层组织为回火马氏体,伸长率极低,加速了疲劳裂纹的扩展;基体组织为保持马氏体位相的回火索氏体,冲击吸收能量较低,促进了连铸辊的疲劳断裂。

英文摘要：

Early fracture failure of the continuous casting roller manufactured by 21 CrMo V5. 11 steel was analysed by fracture morphology,chemical composition,microstructure and mechanical property test and so on. The results show that the fracture mode of the continuous casting roller is fatigue cracking and fracture sources are circumferential cracks of surfacing layer resulted from improper welding process.Tempered martensite microstructure of surfacing layer with low elongation accelerates the propagation of the fatigue crack. And the tempered sorbite matrix microstructure keeps martensite phase location with very low impact absorption energy promoting fatigue fracture.