Nitrogen alloyed martensitic stainless steel and process

摘要

The present invention comprises a process for nitriding martensitic stainless steel and the alloy produced thereby comprising heating a stainless steel alloy to a temperature of from about 900° F. (480° C.) to about 2500° F. (1370° C.) in a vacuum furnace in the presence of hydrogen or argon gas in order to clean the surface. After the hydrogen or argon gas is removed from the chamber, nitrogen gas, or a different nitrogen gas derivative is injected into said furnace as a pulsed injection at a partial pressure of from about 500 torr to about 1000 torr. The steel is nitrogen alloyed at a temperature of from about 1400° F. (760° C.) to about 2200° F. (1205° C.) and then quickly quenched at ambient temperature. Preferably, after a sufficient period of time, the temperature is raised a second time from about 900° F. (480° C.) to about 2500° F. (1370° C.) prior to cooling the final product.

主权项

1. A process for nitriding martensitic stainless steels comprising:
a. heating martensitic stainless steels to a temperature of from about 900° F. (480° C.) to about 2500° F. (1370° C.) in a vacuum furnace in the presence of hydrogen or argon gas in order to clean the surface thereof; b. subsequently removing the hydrogen or argon gas from said furnace; c. injecting nitrogen (N2) gas, ammonia gas (NH3) or mixtures thereof as a pulsed injection into the chamber of said furnace which is at a partial atmospheric pressure of from about 500 torr to about 700 torr; d. nitrating said steel at a temperature of from about 1400° F. (760° C.) to about 2200° F. (1205° C.); e. quenching said steel, and, f. raising the temperature of the chamber in said furnace a second time from about 900° F. (480° C.) to about 2500° F. (1370° C.) prior to cooling the final product.