Improved corrosion resistance of powder manufactured AISI 904L parts by hot isostatic pressing post treatment

Metal binder jetting (MBJ) of AISI 904L super austenitic stainless steel makes it possible to produce complex components with a higher corrosion resistance compared to austenitic stainless steels such as AISI 304L and AISI 316L. The initial sintering trials resulted in a porous part with low corrosion resistance. As AISI 904L is a steel with austenitic phase throughout the entire sintering window, densification during sintering was inhibited which resulted in the reduced corrosion resistance due to open porosities. The trials were made with AISI 904L powder suited for MBJ but shaped through metal powder extrusion due to lack of printer availability. This paper will show how to enhance densification and utilize pickling in order to improve the corrosion resistance closer to the expected level comparable to cast and rolled material but with the shaping possibilities of MBJ.