For the purpose of fabricating ultra-high nitrogen austenitic steels (>1mass%N), the phenomenon of nitrogen absorption into solid solution was thermodynamically analyzed and applied to Fe-Cr-Mn system ternary alloy. During the annealing of the steel in a nitrogen gas atmosphere of 0.1 MPa at 1473 K (nitrogen absorption treatment), the nitrogen content of the steel was increased with the absorption of nitrogen gas from the material surface and then saturated when the system reached a state of equilibrium. The effect of the steel composition on the equilibrium nitrogen content was formulated taking account of interactions among Cr, Mn and N atoms, and the condition for fabrication of ultra-high nitrogen austenitic steels was clarified. The nitrogen addition to ultra-high content markedly increased proof stress and tensile stress of the austenitic steels without losing moderate ductility. For example, Fe-24Cr-10Mn-1.43N (mass%) alloy has 830 MPa in 0.2% proof stress, 2.2 GPa in true tensile stress and 75% in total elongation.
|ジャーナル||Materials Science Forum|
|出版ステータス||出版済み - 1月 1 2003|
|イベント||Thermec 2003 Processing and Manufacturing of Advanced Materials - Madrid, スペイン|
継続期間: 7月 7 2003 → 7月 11 2003
!!!All Science Journal Classification (ASJC) codes