管口堆焊复合管是碳钢管内衬薄壁不锈钢管,管端内壁距坡口30 mm由焊丝堆焊出不锈钢层。采用这类复合管对接时可以使用异种钢焊丝一次完成焊道的根焊和过渡焊,比常规复合管省掉了封焊、切割、坡口加工等工序,提高了工作效率。但管端堆焊时容易产生应力集中、管口收缩变形的情况,甚至产生裂纹。因此这类复合管的使用在带来施工方便、提高工作效率的好处的同时,控制现场堆焊质量又成为新的技术难题。通过科学设计接头的坡口形式和尺寸,制定焊道的焊接顺序和操作技术要求,成功地解决了这类双金属复合管的焊接问题,同时研究出适用于野外作业的端部处理技术,保证了这类双金属焊接质量和安装效率。通过研究总结和成功应用,为今后管口堆焊复合管施工积累了经验。

Nozzle surfacing bimetal pipe is carbon steel pipe lined with thin-walled stainless steel tube, and stainless steel layer is built up 30mm from inner wall of the pipe end to groove by welding wire.When the composite pipe is used for butt joint, different steel welding wires can be used to complete the root welding and transition welding of the welding channel at one time, so that sealing welding, cutting, groove processing and other processes are omitted compared with the conventional composite pipe, and the working efficiency is improved.However, the stress concentration and the contraction and deformation of the nozzle are easily occurred when the pipe ends surfacing is being performed, and even cracks are generated.Therefore, while the use of this kind of composite pipe brings convenience to the project and improves the working efficiency, controlling the quality of on-site surfacing has become a new technical issue in construction.By scientifically designing the groove form and size of the joint, defining welding sequence and technical requirements of the welding channel, the welding issue of the bimetallic composite pipe is successfully solved, and the end treatment technology suitable for field operation is developed, so that the welding quality and installation efficiency of the bimetallic composite pipe are guaranteed. Through the summary and application, experience is accumulated for the construction of pipe surfacing bimetal pipe in the future.