| Title |
The Effect of Nitrogne on the Grain Boundary Precipitation and Sensitization of Type 316L Stainless Steels |
| Authors |
오용준(Yong Jun Oh) ; 류우석(Woo Seog Ryu) ; 홍준화(Jun Hwa Hong) |
| Abstract |
Nitrogen effect on sensitization behavior of type 316L stainless steel was investigated in view of thermal precipitation. The investigated alloys had a variation in carbon and nitrogen contents. The sensitization resistance was improved with decreasing of carbon content and increasing of nitrogen content. From a microstructural observation on the sensitized alloys, it was found that the addition of nitrogen up to 0.15% increased sensitization resistance through suppressing the initiation and growth of M_(23)C_6 type carbide. M_6C type carbide was only formed at the alloy with medium nitrogen content. Besides carbides, Mo-rich precipitates such as intermetallic η and χ phases, and five-fold symmetry phase were observed at the grain boundary. These phases were more popular in the medium nitrogen alloy than in low nitrogen alloy at the same aging condition. From a TEM-EDS(energy despersive spectroscope) analysis, it was found that these Mo-rich phases had not a significant deterimental effect on the sensitization resistance. |