The nonisothermal multipass deformation behavior of as-cast 42CrMo alloy was studied with declining temperature, constant pass strain, varying strain rate, and interval time. The stresses are used to develop the constitutive model. As the finishing temperature increases from 990°C to 1070°C, the stress decreases gradually and the softening effect increases, which results in a large grain size and inhomogeneous microstructure. The low angle grain boundaries transform into high angle grain boundaries through absorbing dislocations. The noticeable stress softening in a high strain rate is attributed to the thermal softening, dynamic recovery, and dynamic recrystallization. The thermal softening is no longer considered to be the main interpass softening mechanism at a low strain rate. The interval time has a negligible effect on the stress, but the significant changes in grain size and texture component are caused by the interpass softening. The average grain size is approximately 40 μm, and the distorted grain boundaries and small fine grains are found in the interval times of 0.5–5 s, implying the dynamic recovery and grain growth. The near {001}<110> and {110}<112> orientation exerts an important influence on the grain refinement.

中文翻译：

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铸态42CrMo合金非等温多道次压缩的本构特征，显微组织和组织演变

研究了铸态42CrMo合金的非等温多道次变形行为，其中包括温度下降，道次恒定应变，变化的应变速率和间隔时间。应力用于建立本构模型。当最终温度从990°C升高到1070°C时，应力逐渐降低，软化效果增强，这会导致较大的晶粒尺寸和不均匀的微观结构。低角度晶界通过吸收位错转变成高角度晶界。高应变速率下明显的应力软化归因于热软化，动态恢复和动态再结晶。在低应变速率下，热软化不再被认为是主要的道间软化机制。间隔时间对压力的影响可以忽略不计，但是晶粒尺寸和织构成分的显着变化是由道次软化引起的。平均晶粒尺寸约为40 μ m和失真晶界和小细颗粒在0.5-5 S中的间隔时间被发现，这意味着动态恢复和晶粒生长。{001} <110>和{110} <112>附近的取向对晶粒细化产生重要影响。