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本文利用着色探伤、低倍检验、金相分析、显微硬度及电子探针等方法，分析了某化肥厂一段转化炉炉管沿异种纲焊接融合区的爆裂事故。研究结果表明：４Ｃｒ２５Ｎｉ２０钢与１（１／４）Ｃｒ（１／２）Ｍｏ钢焊接融合区，在５００℃左右， 近２００００小时的运行中，１（１／４）Ｃｒ（１／２）Ｍｏ钢接近融合线部位，由于碳向焊缝扩散而发 生脱碳现象，沿异种钢的融合线折出薄壳状脆性碳化物相，融合区硬度升高，这是导 致融合区韧性下降，引起炉管沿融合线断裂的主要原因。
In this paper, using the methods of color inspection, low magnification, metallographic analysis, microhardness and electron probe, the burst accident along the heterogeneous weld fusion zone in the first-stage reformer tube of a fertilizer plant was analyzed. The results show that 1 (1/4) Cr (1/2) Mo (subscript Mo) is the most suitable for the welding of 4Cr25Ni20 steel and 1 (1/4) Cr As the steel approaches the fusion line, decarburization occurs as the carbon diffuses into the weld and the shell-like brittle carbide phase breaks out along the fusion line of the dissimilar steels, increasing the hardness of the fusion zone, which leads to a decrease in the toughness of the fusion zone, Tube along the fusion line the main reason for the fracture.