| Title |
The Effect of Cold Work on Grain Boundary Precipitaion and Sensitization in Nitrogen Added Type 316L Stainless Steels |
| Authors |
서무홍(Moo Hong Seo); 오용준(Yong Jun Oh); 유우석(Woo Seog Ryu); 천병선(Byong Sun Chun); 홍준화(Jun Hwa Hong) |
| Keywords |
Type 316L stainless steels; Sensitization; Cold work; Nitrogen addition |
| Abstract |
The precipitaion and sensitization behavior of nitrogen added Type 316L stainless steels(SS) were investigated by using specimens cold worked for 0~40%. The alloys had a variation in nitrogen content from 0.04 to 0.15%. To quantify the degree of sensitization double-loop electrochemical potentiokinetic reactivation (DL-EPR test was performed in a 0.1M H2SO4 + 0.01M KSCN solution at 30℃. The addition of nitrogen increased sensitization resistance by retarding the onset of M23C6 precipitation and shifted Time-Temperature-Sensitization (TTS) curve to higher temperature and longer time range. Cold work accelerated the M23C6, precipitation and sensitization kinetic due to the increase in dislocation density. However, the acceleration of sensitization was found to depend on the added nitrogen content in the alloys. The alloys with high nitrogen(>0.1%N) content exhibited higher accelation of the sensitization as a function of the cold work than that with low nitrogen content. From the microstructural analysis, this was found to he attributed to the development of intensive slip bands during cold work and retardation of dislocation annihilation during subsequent aging in the alloys with high nitrogen content. |