40Cr钢法兰焊接接头断裂原因分析

摘要

The reasons of fracture of 40Cr welding flange were analyzed on the basis of macro observation, metallurgical, chemical composition analysis, etc. The results showed that the 40Cr welding flange existed the defects of root crack, toe crack, lack of fusion, and incomplete penetration, etc. The root crack will expend under the exerting of the stress, leading to fracture during application. The root crack caused by improper welding operation was the main cause for fracture at early stage. The paper also proposed the improvement suggestion for welding process.%通过宏观观察、金相分析和化学成分分析等方法,对40Cr钢法兰焊接接头的断裂原因进行了分析.结果表明,40Cr钢法兰焊接接头存在根部裂纹、焊趾裂纹、未熔合和未焊透等焊接缺陷,在应力的作用下,根部裂纹发生扩展,造成接头在使用过程中发生断裂.焊接工艺及操作不当导致法兰焊接接头产生根部裂纹,是其发生早期断裂的主要原因,并对焊接工艺提出了改进建议.