25Cr-35Ni-Nb裂解炉管焊接工艺要点

裂解炉管用25Cr-35Ni-Nb材料属于离心铸造的高镍铬热强钢，化学成分较为复杂，在焊接过程中焊缝金属具有较大的结晶裂纹倾向，对焊接环境及施工要求较严格。通过对25Cr-35Ni-Nb材料的焊接性分析及焊接操作实践，掌握了该材料的焊接工艺要点、注意事项及焊接参数。通过优化焊接工艺参数，在工程承接的某烯烃裂解项目用裂解炉管的一次焊接合格率达到99.9%以上。

Welding Process of 25Cr-35Ni-Nb Cracking Furnace Pipe

25Cr-35Ni-Nb material for cracking furnace pipe is a high Ni-Cr thermal strength steel cast by centrifugal casting and the chemical composition is complex. The weld metal has a large tendency of crystallization crack during welding, and the requirements for welding environment and construction is strict. Through the weldability analysis and welding operation practice of 25Cr-35Ni-Nb material, the main points of welding process, precautions and welding parameters of the material are mastered. By optimizing the welding process parameters, the one-time welding qualification rate of cracking furnace pipe for an olefin cracking project undertaken by the project has reached more than 99.9%.