The most famous is the following formula: Austenitic forming ability of =Ni%+30C%+30N%+0.5Mn%+0.25Cu%From this equation can be seen: carbon is a strong austenite forming elements, the formation of austenite is the nickel 30 times, but it cannot be added to the corrosion of stainless steel after welding, because it will cause the corrosion problem of sensitized intergranular corrosion and subsequent.30 times the nitrogen austenitic formation ability is also a nickel, but it is a gas, do not want to cause porous, stainless steel packing buckle "-" stainless steel flat buckle "-" stainless steel tooth "only in a limited number of nitrogen added in stainless steel. Addition of manganese and copper will cause fire life and reduce the problems in the process of welding steel. Recently held in Seoul ISSF (forum of international iron and Steel Association Conference stainless steel) prediction, part of the market at low nickel austenitic stainless steel and 200 stainless steel could replace 300 series stainless steel raw material supply, this year will not be a serious shortage situation. Only 200 series stainless steel tube corrosion resistance is better than 300, therefore, China should consider the development of stainless steel application specification.