Abstract: The production difficulties of super duplex stainless steel 6A pump castings were introduced, and the key technologies of the casting were analyzed, including smelting and composition control, casting process, heat treatment process and welding process. After adopting appropriate technological measures, the qualified super duplex stainless steel 6A castings were successfully obtained. The castings tested by a full-piece one-time PT（penetration test） was qualified, and their chemical composition and mechanical properties met the requirements of ASTM standard. At the same time, the welding process of 6A stainless steel was studied, and the suitable welding parameters were found, and the mechanical properties of the welded joint met the requirements.