为了控制Mn18Cr18N护环钢热锻后的组织和性能,通过热模拟压缩试验研究了该钢在900~1200℃、应变速率为0.001~0.1s-1和初始晶粒尺寸为48~230 μm条件下的动态再结晶行为,建立了双曲本构模型,结合双曲本构模型和动态材料模型构建了热加工功率耗散图:通过功率耗散图和微观组织对锻造过程变形温度和应变速率进行了分析.结果表明:当变形温度不高于1 100℃时,随着应变速率的降低和温度的升高,功率耗散率ηJ逐渐增大:当温度高于1 100℃后规律相反:当ηJ不小于0.2时,该钢可获得均匀细化的完全动态再结晶组织.

To control the microstructure and properties of retaining ring steel after hot forging,the dynamic behavior of Mn18Cr18N retaining ring steel was investigated by thermomechanical compression test under the conditions of experimental temperature from 900℃ to 1 200℃,strain rate from 0.001 s-1 to 0.1 s-1 and initial grain size from 48 μm to 230 μm.The hyperbolic constitutive model was established.Based on the hyperbolic constitutive model and dynamic material model,the iso-efficiency map was constructed.Through power dissipation map and microstructure analysis,the deformation temperature and deformation rate duing casting were studied.The results show that the power dissipation rate ηJ increased with the decrease of strain rate and the increase of temperature when the deformation temperature was not higher than 1 100℃,however,changes were opposite when higher than 1 100℃.The fine homogenized and completely dynamic recrystallization could be obtained when the ηJ was not smaller than 0.2.