Various welding methods for stainless steel welded pipes have their own advantages and disadvantages. How to improve strengths and avoid weaknesses, combine several welding methods to form a new welding process to meet people's requirements for stainless steel welded pipe quality and production efficiency, is a new trend in the development of stainless steel welded pipe technology. After several years of exploration and research, the combined welding process has made progress, and Japan, France and other countries have mastered certain welding techniques for the production of stainless steel welded pipe. Combination welding methods are: argon arc welding + plasma welding, high frequency welding + plasma welding, high frequency preheating + three torch argon arc welding, high frequency preheating + plasma welding + argon arc welding. Combined welding increases the welding speed significantly. For combined welding with high-frequency preheating, the quality of welded steel pipe is equivalent to conventional argon arc welding and plasma welding. The welding operation is simple, and the entire welding system is easy to automate. This combination is easy to connect with existing high-frequency welding equipment. Low investment costs and good returns.