终轧温度对高氮奥氏体钢组织和力学性能的影响

通过加压冶炼、控制轧制方式获得氮质量分数为0.59%的Mn18Cr18N钢板,研究了终轧温度对高氮奥氏体钢组织和力学性能的影响。结果表明,在再结晶区轧制并且终轧温度为970 ℃的钢板,组织为奥氏体等轴晶和部分孪晶,强度较低,塑性、冲击韧性较好;终轧温度为910 ℃的钢板,大部分组织为变形奥氏体晶粒,有少量再结晶晶粒,随着终轧温度降低钢板强度升高,塑性和冲击韧性降低;在未再结晶区轧制并且终轧温度为780 ℃的钢板,组织为变形严重的奥氏体晶粒,强度最高,塑性、韧性最低。所有试验钢有晶界析出的Cr₂N相,降低终轧温度和减缓轧后冷却速度,会增加Cr₂N相的析出。

Effects of finish rolling temperature on microstructure and mechanical properties of high nitrogen austenitic steel

Mn18Cr18N steel plate with nitrogen mass fraction of 0.59% was obtained by pressurized metallurgy and controlled rolling technology. The effects of finish rolling temperature on microstructure and mechanical properties of high nitrogen austenitic steel were investigated. After recrystallization zone rolling and finish rolling at 970 ℃, the steel plates consisted of equiaxed austenite and some twins, with lower strength, higher ductility and impact toughness. After finish rolling at 910 ℃, the steel plates consisted of most deformed austenite and some recrystallization grains. The strength increased, the ductility and the impact toughness decreased with the decrease of finish rolling temperature. After non-recrystallization zone rolling and finish rolling at 780 ℃, the steel plates consisted of severe deformed austenite, with the highest strength, the lowest ductility and impact toughness. The precipitation Cr₂N formed along grain boundary which could be found in all plates. The quantity of precipitation Cr₂N increased with the decrease of finish rolling temperature and cooling rate after rolling.