316LN高氮超低碳奥氏体不锈钢的热变形行为和组织演变

试验的316LN钢（/%:0.011C,0.49Si,1.52Mn,0.016P,0.001S,16.65Cr,13.43Ni,2.18Mo,0.153N）为7.2 t铸锭初轧开坯并锻造成的Φ180 mm圆钢。利用Gleeble-3800热模拟试验机研究了316LN钢在应变速率0.1~50 s^-1、1050~1200℃时的热变形行为和组织演变规律,并通过线性回归分析建立了316LN钢的本构方程。结果表明,变形温度升高有利于动态再结晶的形核,并在热变形过程中促进动态再结晶扩展;热变形过程材料常数α为0.0061,应力指数n为5.5436,表观激活能550.512 kJ/mol,动态再结晶晶粒数量随着变形温度的增加而增多,到1 200℃变形时发生了完全的动态再结晶。

Hot Deformation Behavior and Structure Evolution of High Nitrogen Ultra-Low-Carbon Austenite Stainless Steel 316LN

The test steel 316LN (/% : 0.011C, 0.49Si, 1.52Mn, 0.016P, 0.001S, 16.65Cr, 13.43Ni, 2.18Mo, 0. 153N) is Φ 180 mm round bar forged and primary-rolled from 7. 2 t ingot. The hot deformation behavior and structure evolution rule of steel 316LN with strain rate 0. 1 ~ 50 s^-1 at 1 050 ~ 1 200 ℃ has been studied by using thermal-simulated test machine Gleeble-3800, and a constitutive equation of steel 316LN is established by linear regression analysis. Results show that increase of deformation temperature is favorable for nucleation of dynamic recrystallization and promoting the development of dynamic recrystallization during hot deformation; in hot deformation process the material constant α is 0.006 1, the stress exponent n is 5.543 6 and the apparent activation energy is 550. 512 kJ/mol； with increasing deformation temperature the number of dynamic recrystallized grains in steel increases, and the complete dynamic recrystallization occurs in steel deformed at 1 200 ℃.