Mainly used in the food industry and surgical instruments, the addition of molybdenum gives it a special structure that is resistant to corrosion. Compared to 304, it has better resistance to chloride corrosion, thus it is also used as 'marine steel'. SS316 is commonly used in nuclear fuel recycling devices. 18/10 grade stainless steel usually also meets this application level.
　　To save stainless steel materials, a welded ring form is used. This structure must have the sealing surface processed after the welded ring and the connecting pipe are welded together. Generally, it is used under an operating pressure of 2.5 MPa. Smooth surface welded flanges are not suitable for equipment that requires high airtightness for toxic and flammable explosive media due to their poor connection rigidity and sealing performance.
　　The connecting disc material of this structure uses carbon steel or stainless steel. If carbon steel is used, the surface needs to be nickel-plated, and the clamp material is made of cast aluminum ZL7. The sealing roughness of the connecting disc is 20, and there must be no obvious radial grooves and scratches. The specific structure can be seen in GB4982-85.