Impact properties of sintered and wrought 17–4 PH stainless steel

Abstract

Charpy V notch (CVN) impact testing was conducted on full size and subsize specimens of sintered and wrought 17–4 PH stainless steel (17–4 PH SS) in the as sintered and H900 heat treated conditions. Test geometries correspond to the American Society for Testing and Materials (ASTM) and Metal Powder Industries Federation (MPIF) impact testing standards. Merits of a notched specimen compared with an unnotched specimen were analysed for both the wrought and sintered materials. The notched ASTM standard bars had a lower coefficient of variance for impact energy than the unnotched MPIF standard bars and displayed greater toughness. Porosity and grain size have a detrimental synergistic effect on impact toughness for the sintered material. Following a discussion about the differences in the wrought and sintered microstructures, it is recommended that impact testing of the injection moulded and sintered specimens should be evaluated according to the ASTM test specifications.

Keywords:

• STAINLESS STEEL
• 17-4 PH SS
• SINTERING
• CHARPY TEST
• IMPACT TOUGHNESS
• METAL POWDER INJECTION MOULDING
• TESTING
• SIZE EFFECTS