| 发明名称 |
NITRIDING METHOD AND NITRIDED PART PRODUCTION METHOD |
| 摘要 |
A low alloy steel is heated to a temperature ranging from 550 to 620° C., and high KN and low KN value processes are performed for a total process time of A: 1.5 to 10 hours. In the high KN value process, a nitriding potential KNX given by Formula (1): 0.15 to 1.50, the average KNX value KNXave: 0.30 to 0.80, and the process time is X in hours. In the low KN value process, which is performed after the high KN value process, a nitriding potential KNY given by Formula (1): 0.02 to 0.25, the average KNY value KNYave: 0.03 to 0.20, and the process time is Y in hours. Average nitriding potential value KNave determined by Formula (2) ranges from 0.07 to 0.30.;KNi=(NH3 partial pressure)/(H2 partial pressure)3/2] (1);KNave=(X×KNXave+Y×KNYave)/A (2)where i is X or Y. |
| 申请公布号 |
US2017016107(A1) |
申请公布日期 |
2017.01.19 |
| 申请号 |
US201515123732 |
申请日期 |
2015.03.10 |
| 申请人 |
NIPPON STEEL & SUMITOMO METAL CORPORATION |
发明人 |
UMEHARA Takahide;DAITO Yoshihiro |
| 分类号 |
C23C8/26 |
主分类号 |
C23C8/26 |
| 代理机构 |
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代理人 |
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| 主权项 |
1. A nitriding method, comprising a gas nitriding step in which a low alloy steel is heated to a temperature ranging from 550 to 620° C. in a gas atmosphere containing NH3, H2, and N2, the gas nitriding step being performed for a total process time of A ranging from 1.5 to 10 hours,
the gas nitriding step including the steps of: performing a high KN value process with a nitriding potential KNX determined by Formula (1) ranging from 0.15 to 1.50 and with an average value KNXave of the nitriding potential KNX, the average value KNXave ranging from 0.30 to 0.80, the high KN value process being performed for a process time of X in hours, and performing a low KN value process after the high KN value process, the low KN value process being performed with a nitriding potential KNY determined by Formula (1) ranging from 0.02 to 0.25 and with an average value KNYave of the nitriding potential KNY, the average value KNYave ranging from 0.03 to 0.20, the low KN value process being performed for a process time of Y in hours, wherein an average nitriding potential value KNave determined by Formula (2) ranges from 0.07 to 0.30,
KNi=(NH3 partial pressure)/[(H2 partial pressure)3/2] (1)KNave=(X×KNXave+Y×KNYave)/A (2) where i is X or Y. |
| 地址 |
Tokyo JP |
