温压缩变形过程中渗碳体的球化行为

Spheroidization behavior of cementite during warm compression deformation

在Gleeble-3500热模拟试验机上对原始组织为层片状珠光体的高碳钢进行温度为640-700℃、应变速率0．01-10s^-1，最大真应变为1的温压缩变形，采用扫描电镜研究了该过程中渗碳体片层的组织演变情况，并用DEFORM-3D软件模拟了温变形过程中试样内部等效应变的分布情况。结果表明，温压缩变形过程中存在着形变不均匀性，使得试样心部和边缘组织形态有明显差异，随着应变速率的降低，边缘层片状珠光体组织球化为粒状珠光体；在变形过程中珠光体组织主要发生渗碳体片层的球化，随着应变量、应变速率以及变形温度的增加，渗碳体球化率明显增大。

Using a Gleeble-3500 simulator, the warm compression deformation with the maximum true strain of 1 for high carbon steel with lamellar pearlite was performed in the rang of temperature from 640℃ to 700℃ and with the strain rate range from 0.01 to 10s^-1 .The structure evolution of the lamellar cementite was investigated by scanning electron microscopy （SEM）, and the distribution of equivalent strain in the deformed specimen was simulated with DEFORM-3D software during the warm deformation process. The results show that the microstructure differences in the center and the edge of the deformed specimen are evident due to the inhomogeneity of deformation. Lamellar pearlite in the edge of the specimen is spheroidized gradually to granular pearlite with the strain rate decreasing. During the deformation process the lamellar cementite of pearlite mostly was spheroidized. With the amount of strain, stain rate and deformation temperature increasing the spheroidization rate of cementite enhances markedly.