Influence of processing parameters on the characteristics of surface layers of low temperature plasma nitrocarburized AISI 630 martensitic stainless steelInfluence of processing parameters on the characteristics of surface layers of low temperature plasma nitrocarburized AISI 630 martensitic stainless steel

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 Author Lee, Insup Source SpringerLink Content type Text Publisher The Korean Institute of Metals and Materials File Format PDF Copyright Year ©2017 Language English
 Subject Domain (in DDC) Technology ♦ Engineering & allied operations Subject Keyword plasma nitrocarburizing ♦ AISI 630 stainless steel ♦ expanded martensite layer ♦ corrosion resistance ♦ discharge voltage ♦ Metallic Materials ♦ Operating Procedures, Materials Treatment ♦ Magnetism, Magnetic Materials ♦ Engineering Thermodynamics, Heat and Mass Transfer ♦ Characterization and Evaluation of Materials ♦ Continuum Mechanics and Mechanics of Materials Abstract Plasma nitrocarburizing was performed on solution-treated AISI 630 martensitic precipitation hardening stainless steel samples with a gas mixture of H$_{2}$, N$_{2}$, and CH$_{4}$ with changing temperature, discharge voltage and amount of CH$_{4}$. When nitrocarburized with increasing temperature from 380 °C to 430 °C at fixed 25% N$_{2}$ and 6% CH$_{4}$, the thickness of expanded martensite (α'$_{N}$) layer and surface hardness increased up to 10 μm and 1323 HV$_{0.05}$, respectively but the corrosion resistance decreased. Though the increase of discharge voltage from 400 V to 600 V increased α'$_{N}$ layer thickness and surface hardness (up to 13 μm and 1491 HV$_{0.05}$, respectively), the treated samples still showed very poor corrosion behavior. Thus, to further improve the corrosion resistance, the influence of variation of the amount of CH$_{4}$ in the nitrocarburizing process was investigated. Increasing the CH$_{4}$ percentage aided higher corrosion resistance, although it decreased the α'$_{N}$ layer thickness. The most appropriate conditions for moderate α'$_{N}$ layer thickness, high surface hardness and better corrosion resistance than the solution-treated bare sample were established, which is plasma nitrocarburizing at 400 °C with 400 V discharge voltage and containing 25% N$_{2}$ and 4% CH$_{4}$. ISSN 15989623 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 2017-11-14 Publisher Place Seoul e-ISSN 20054149 Journal Metals and Materials Volume Number 23 Issue Number 6 Page Count 9 Starting Page 1112 Ending Page 1120