| Title |
Research Paper / Trasformations : Dissolution Behavior of Nitrogen in Fe - Mn - Cr - Ni System Austenitic Stainless Steel |
| Authors |
김형걸(Byung Geol Kim); 김봉서(Bong Seo Kim); 유경재(Kyung Jae Yoo); 권해웅(Hae Woong Kwon); 이희웅(Hee Woong Lee) |
| Abstract |
Induction melting method under pressurized nitrogen gas was used to produce austenitic stainless steels dissolved with high content of nitrogen. Fe-Mn-Cr-Ni allay system was melted using Cr-nitride ferrous allay(6wt.% N) as a main additive element. The concentration and dissolution behaviors of nitrogen in as-casted alloys were investigated to clarify the effectiveness of induction melting method under pressurized nitrogen gas and Cr-nitride ferrous alloy in producing high nitrogen austenitic stainless steels having excellent mechanical, corrosion-resistance and non-magnetic properties. Nitrogen concentration in molten alloys was increased with increasing nitrogen pressure up to 1.5 atm. This result can be explained by Sievert`s law. The nitrogen concentration of about 6.900 ppm was obtained in a molten alloy when melted at the nitrogen pressure of 1.5 atm. XRD and XPS measurements were carried out to investigate the dissolution behavior of nitrogen in a molten alloy. Although it was failed to detect some nitrides by XRD, XPS measurement revealed the existence of nitride such as Cr₂N. Therefore it can be concluded that the dissolved nitrogen in a molten alloy exists as two states, one is as a solid solution state, the other is as a nitride state. It seems reasonable to conclude the most of nitrogen were dissloved as a solid solution state, and some nitrogen are apt to be formed into a nitride. |