With the development of globalization, more and more attention has been paid to improving the engine emission temperature and realizing the low emission and lightweight performance in automobile manufacturing. Therefore, more and more welding stainless steel exhaust pipe technology has been applied in automobile manufacturing process. Different from the original cast iron exhaust pipe, the stainless steel exhaust pipe can meet the casting temperature to the greatest extent, and can bear a high temperature limit when working, and the weight reduction effect of the stainless steel exhaust pipe is also very good.

When welding stainless steel exhaust pipe, two casting methods are generally used. One is to continuously press stainless steel material to make it formed, and then weld it. The other is to weld the stainless steel after expanding. These two methods are very flexible in the selection of materials, many materials can be used, and the manufacturing technology is also very advanced. Generally, laser welding technology is used, which can not only fully improve the process quality, improve the accuracy, reduce the error rate, improve the success rate and improve the efficiency, but also has great elasticity, and the produced steel pipe has various properties and strong heat resistance.

Therefore, this technology is adopted by more and more automobile parts manufacturing companies, and has a good development prospect. The exhaust manifold welded by this method not only greatly improves the heat resistance temperature, but also has good overall performance, which is more durable than the traditional iron casting. At present, it has achieved large-scale mass production. However, there are still many shortcomings in the welded stainless steel exhaust pipe produced by laser welding technology, such as higher cost, higher noise, substandard stiffness and low product accuracy. At present, many domestic automobile enterprises have optimized and upgraded the technology, and the most representative is Harbin Institute of technology, which has developed an internal high pressure forming technology However, because the technology is not mature enough, there is no mass production, and further production practice is needed.