Microstructure and properties of dissimilar metal welds of ferritic and austenitic stainless steels

Microstructure of dissimilar welding joint between ferritic stainless steel and austenitic stainless steel and its effect on properties were investigated.The result shows that the microstructure of welded seam is a mixture of δ-ferrite and austenite,and the morphology and content of δ-ferrite in different area of the weld seam are significantly different.The microhardness varies with the morphology and content of δ-ferrite,and acicular δ-ferrite can increase the microharness of weld seam.Furthermore,the impact toughness of base metal and heat-affect zone of 443 stainless steel is worse than that of 304 austenitic stainless steel;moreover,the impact absorbing energy decreases dramatically with the decrease of temperature and ductile fracture and brittle fracture occurs at room temperature and at-20 ℃,respectively.