The reasons for the difficulty of stainless steel welding process are as follows：
1. stainless steel material thermal sensitivity is strong, stay in 450 ~ 850℃ temperature zone slightly longer, weld and heat affected zone corrosion resistance will be seriously reduced;

2. prone to thermal crack;

3. poor protection, high temperature oxidation is serious;

4. Large linear expansion coefficient, easy to produce large welding deformation.