Microstructure of welded joint of super304 austenitic steel used for ESC boiler

Argon-arc welding was conducted for the super304H austenitic stainless steel and its weld microstructure was studied. The results show that almost no crack and deformation could be found in weld bead after welding by 210 A direct current. The microstructure of austenite is a small amount of granular carbides containing Nb, presenting tree-like and reticulated structures after cankered. The weld bead and the substrate combined well, without obvious heat-affected zone. The precipitated phase of Cr could not be found on the grain boundary near the weld bead, but the distribution of Cr element in weld microstructure is non-homogeneous.