Austenitic stainless steel welding often has problems

Weld hot crack

During the welding process, the weld-around cracks are very likely to appear in the weld-around zone, while the heat-affected zone (HAZ) or the metal between the multi-layer weld beads may appear to be liquefied. In order to prevent this weld hot crack defect, firstly, we must strictly control the weld metal structure and the content of harmful impurity elements, and adjust the chemical composition of the weld as much as possible, and try to make the weld metal have austenite-ferrite summer structure; 2. When welding, small specifications should be adopted as much as possible, fast welding speed to reduce the degree of overheating of the weld pool, and to reduce segregation, can also prevent the formation of thick columnar products, and effectively prevent cracks.

Intergranular corrosion of welded joints

When austenitic stainless steel welded parts work in corrosive media, local corrosion along the grain boundary may occur at the weld, which will cause the decline of metal mechanical properties and corrosion properties. In order to prevent the occurrence of this problem, appropriate electrodes, wires, fluxes, etc. should be selected so that the weld box contains appropriate alloying elements and content, which can effectively avoid the occurrence of crystal intercalation corrosion defects; in addition, select the welding method with the smallest heat input In addition, after welding, the weld on the side contacting the medium should be solid solution treated as the last weld as possible.

Post-weld heat treatment

After austenitic stainless steel is welded, post-weld heat treatment is generally not required. If the performance requirements of the welded workpiece are high, low-temperature, medium-temperature or high-temperature post-weld heat treatment can be selected according to the actual situation.