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针对30CrMnSiA碰撞断裂样品,经宏观分析并采用扫描电子显微镜微观断口观察,配合能谱仪成分分析,及金相显微镜组织观察可知,断面原有陈旧性大裂纹,深达管厚一半,碰撞断裂起始于陈旧裂纹根部,是陈旧裂纹再扩展。主裂缝根部晶粒粗大,缝旁有大型氧化铝夹渣及点状内氧化物,缝边脱碳,陈旧裂纹形成与穿管有关。穿管裂纹与大型夹渣及局域粗晶,共同造成碰撞非正常断裂。其中,夹杂物和粗晶区域是管材断裂主要原因。
According to the results of macro analysis, microscopic fracture observation of scanning electron microscopy (SEM), composition analysis of energy spectrometer and microstructure observation of metallurgical microscope, we can see that the original large cracks in the section of the fracture are 30CrMnSiA, Beginning at the root of an old crack, it is an extension of the old crack. The main cracks at the root of coarse grains, seams next to a large alumina slag and point-like oxide, seam edge decarburization, the formation of old cracks and through the tube. Wearing tube cracks and large-scale slag and local coarse grain, common collision caused by abnormal rupture. Among them, the inclusions and coarse grain area is the main reason for pipe fracture.