针对一台中压换热器换热管在同一部位两次产生多根环向开裂现象，本文通过以下三个方面进行裂纹产生的原因分析：第一是胀管产生的换热管轴向应力计算；第二是工艺过程中热量交换引起的物理腐蚀；第三是工艺介质与换热器的材料及拉应力状态三种条件匹配而产生的不锈钢应力腐蚀，从而认为此现象是由特殊工况同作用时产生的组合腐蚀造成的。同时提出了从胀接的工艺次序、管程介质硫含量的控制、选用其他的换热管材料、换热器结构的改变等四个方面消除开裂的途径，可供同行在类似设备设计和制造时借鉴。“,”For a circumferential crack phenomenon of heat transfer tube which appears twice at the same position in a medium-pressure heat exchanger, this paper analyzes from three aspects: the calculation of axial stress in heat transfer tubes produced by tube, physical corrosion caused by heat exchange in the process and stress corrosion of stainless steel caused by process media. So it is believed that this phenomenon is caused by the combined corrosion of the special working conditions. At the same time, it proposes the ways to reduce the corrosion such as the process sequence of expansion, the control of sulfur content in tube side media, the selection of other heat pipe materials and the change of preheater structure, etc. We hope the solutions could be reference in design and manufacture of similar equipments.