Low temperature active-screen plasma surface alloying of precipitation hardening stainless steels

摘要

Precipitation hardening stainless steels are used for a variety of applications in a vast range of industries due to their combination of high mechanical properties, good corrosion resistance and an appropriate level of wear resistance for certain applications. Despite this, the properties of these steels still need to be improved to fit the further requirements needed for more demanding applications. This has work investigated the response of 17-4PH and 17-7PH stainless steels to active screen plasma nitriding and active screen plasma carburising. The main focus was on mechanical propet1ies, corrosion, wear resistance and the formation of the S-phase. The active screen plasma nitriding treatments were conducted for 20 hours at 350(^0)C, 390(^0)C and 430(^0)C in a gas mixture of 25%:N(_2) + 75H(_2) and active screen plasma carburising treatments were conducted at 370(^0)C, 410(^0)C and 450(^0)C in a gas mixture of 1.5CH(_4) and 98.5%H(_2). The thickness of the plasma alloyed layer on both steels increase with the increase in the treatment temperature for both plasma nitriding and carburising.