C型试样淬火及深冷处理过程中变形行为的数值模拟

Numerical Simulation of Distortion Behavior in C-ring Specimen during Quenching and Deep Cryogenic Treatment

基于金属-热-机械耦合模型,采用有限元方法模拟了C型环的淬火和深冷处理过程。并从热应变和组织应变角度出发,揭示了C型环淬火和深冷处理过程中的变形机制。结果表明:淬火过程中较大的心表温差导致局部相互约束产生热应变约-0.0026mm/mm,由相变产生的相变应变为0.0038mm/mm,引起C型环试样发生不均匀拉伸变形,开口和最大直径的尺寸变化分别为0.071和-0.091mm;深冷处理后,试样的热应变-0.0052mm/mm略大于相变应变0.0051mm/mm,开口和最大直径的尺寸变化分别为0.041和-0.132mm。与淬火过程相比,深冷处理通过降低热应变和增大组织应变来稳定C型环的尺寸变化。

Based on the theory of metallic-thermal-mechanical couple model, finite element method was adopted to simulate the quenching (QT) and deep cryogenic treatment (DCT) processes of C-ring specimen. The distortion behavior of C-ring specimen during QT and DCT was revealed from the point of view of thermal strain and microstructural strain. The results showed that during the quenching process, the large temperature difference between surface and center of specimen led to the local mutual constraint and thus generating the thermal strain of about -0.002 6 mm/mm, and the phase transformation strain was 0.003 8 mm/mm, which caused non-uniform tensile deformation of C-ring specimen. The dimensional changes in the opening and the maximum diameter positions were 0.071 mm and -0.091 mm respectively. After DCT, the thermal strain of -0.005 2 mm/mm was slightly larger than the phase transformation strain of 0.005 1 mm/mm, the dimensional changes in the opening and the maximum diameter positions were 0.041 mm and -0.132 mm respectively. The size of C-ring was stabilized by reducing thermal strain and increasing microstructural strain for the DCT as compared with the QT.