Application of 17-7 Precipitation-hardenable Stainless Steel in Dentistry

¹ University of Michigan School of Dentistry, Ann Arbor, Michigan

The tensile and bending qualities, microhardness, and resistance to breakage by bending were determined for 17-7 PH stainless steel in various conditions, and the values were compared with those obtained with 18-8 stainless steel and a cobalt-chromium-nickel alloy.

The properties of the 17-7 PH stainless steel in the cold-worked martensitic condition were comparable to those of the 18-8 stainless steel and the spring-temper condition tion of the cobalt-chromium-nickel alloy, although the yield strength in tension of the 17-7 PH stainless steel was superior to any of the materials examined.

After a precipitation-hardening treatment of 1 hour at 9000 F. the strength properties of the 17-7 PH stainless steel increased markedly and were superior to the other materials. The increase in strength was accompanied by a decrease in ductility, but this decrease was not sufficiently significant to be reflected in the resistance to breakage by bending. Shorter times than 1 hour of heating at 900° F. resulted in less improvement in strength qualities, while heating at 1,3000 F. resulted in overaging and a decrease in properties.