材料期刊网

利用Gleeble-3500热模拟试验机研究了不同变形温度（550、600、650、700℃）和不同变形速率（0.001、0.01、0.1、1、10 s－1）对热轧态中碳钢温变形过程中变形行为的影响，并结合热加工图探明了在细小晶粒铁素体基体上形成均匀分布细小渗碳体颗粒复相组织的最佳工艺窗口。结果表明，温变形过程中，会发生铁素体再结晶以及渗碳体片层动态球化行为，其微观组织演变对流变应力影响较大；根据绘制的热加工图，温变形的适宜温度区间为630～700℃，速率区间为0.30～10和0.001～0.007 s－1，在该工艺区间变形，初始组织转变为细小均匀铁素体基体上分布着细小粒状渗碳体的复相组织。

The warm compression test for medium carbon steel was carried out on Gleeble-3500 thermal-simulation ma-chine. The effects of deformation temperature (550,600,650,700℃) and strain rate (0.001,0.01,0.1,1,10 s-1) on the microstructure evolution were studied. The processing map was established to explore the best parameter combina-tion to generate the evenly distributed and fine cementite particles on the ferrite matrix. The results show that during the warm deformation,dynamic spheroidization of lamellar cementite and ferrite dynamic recrystallization occurred,and the flow stress was influenced by the evolution of microstructure. According to the processing map,the best processing parameter that the temperature range of 630-700℃and the strain of 0.30-10 and 0.001-0.007 s-1 could be obtained. The composite microstructure with ultrafine ferrite grains and uniform distribution of cementite particle was obtained.