耐热合金钢管子-管板仰焊工艺研究及应用

Research and application of heat-resisting alloy steel tube-to-tubesheet welding process in overhead position

某高温换热类设备内件采用耐热低合金钢锻件和耐热低合金钢换热管作为换热介质的承压边界材料,由于产品为特殊的立式结构,管子-管板焊缝的焊接只能在仰焊位置操作。通过工艺研究发现,为了得到质量稳定、焊缝尺寸和形状满足设计和相关技术条件要求的管子-管板仰焊焊接接头,优先选用内缩填丝式管子-管板焊接坡口,合理配比自动钨极氩弧焊工艺参数、控制焊炬角度的同时,还需要严格控制定位胀接参数和焊接操作过程的清洁,制定合理的预热、后热和焊后热处理工艺。

Heat-resisting alloy steel forgings and heat-resisting alloy steel tubes were used as pressure bearing boundary materials of heat exchanger medium in a high-temperature heat exchanger.Due to the special vertical structure of the equipment,the welding operation of the tube-to-tubesheet weld can only be realized in overhead position.It was found through process study,that in order to obtain the tube-to-tubesheet overhead welded joints with stable quality and whose sizes and shapes comply with design and specification,it is preferable to select the groove of tube-to-tubesheet welds with inner shrinking filler wire technology,rationally determine the welding procedure parameters of automatic TIG welding and control the welding torch angle,meanwhile,it is also needed to strictly control the expanding procedure parameters and the cleaning during the welding operation,and work out reasonable preheating,post-heating and post-welding heat treatment process.