ISSN 2594-5327
58th Congresso anual — Vol. 58 , num. 1 (2003)
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Abstract
Nitriding austenitic stainless steel on conventional temperatures near 550ºC is accompanied by an intensive precipitation of chromium nitrides on the diffusion zone. This precipitation promotes a high hardening effect, but lowers the corrosion resistance of the material. To best combine hardening effect and corrosion resistance the nitriding must be carried out at temperatures below 450ºC. For this purpose the plasma nitriding is the best process. This paper describes the plasma nitriding response for an austenitic stainless steel AISI 316L on temperatures of 550ºC and 400ºC, using a gas mixture of 75%N₂:25%H₂ and 25%N₂:75%H₂ for 12 hours at the nitriding temperature. The results show that after nitriding at 550ºC the diffusion zone is formed with the precipitation of nitrides type Fe₄N and CrN. After nitriding at 400ºC no nitrides precipitation is verified and an expanded austenite (γN) is formed. This γN phase is responsible for a strong hardening effect increasing the surface hardness up to ~ 1500 HV, without impairs the corrosion resistance.
Nitriding austenitic stainless steel on conventional temperatures near 550ºC is accompanied by an intensive precipitation of chromium nitrides on the diffusion zone. This precipitation promotes a high hardening effect, but lowers the corrosion resistance of the material. To best combine hardening effect and corrosion resistance the nitriding must be carried out at temperatures below 450ºC. For this purpose the plasma nitriding is the best process. This paper describes the plasma nitriding response for an austenitic stainless steel AISI 316L on temperatures of 550ºC and 400ºC, using a gas mixture of 75%N₂:25%H₂ and 25%N₂:75%H₂ for 12 hours at the nitriding temperature. The results show that after nitriding at 550ºC the diffusion zone is formed with the precipitation of nitrides type Fe₄N and CrN. After nitriding at 400ºC no nitrides precipitation is verified and an expanded austenite (γN) is formed. This γN phase is responsible for a strong hardening effect increasing the surface hardness up to ~ 1500 HV, without impairs the corrosion resistance.
Keywords
plasma nitriding, austenitic stainless steel, expanded austenite
plasma nitriding, austenitic stainless steel, expanded austenite
How to cite
Caetano, Renato Ribeiro; Jr., Adonias Ribeiro Franco; Pinedo, Carlos Eduardo.
LOW TEMPERATURE PLASMA NITRIDED AUSTENITIC STAINLESS STEEL TYPE 316L,
p. 2031-2037.
In: 58th Congresso anual,
Rio de Janeiro, Brasil,
2003.
ISSN: 2594-5327, DOI 10.5151/2594-5327-2814
