中文摘要：

为研究残余元素As、Sn对钢热塑性的影响及稀土La的改善作用,利用Gleeble-1500热模拟机研究了700~1050℃温度范围内含有As、Sn和La的低碳钢的高温热塑性。结果表明,残余元素As、Sn在晶界的偏聚增加了第Ⅲ脆性区的宽度和凹槽的深度,恶化了钢的热塑性。而稀土La的加入固定了钢中部分残余元素,细化了晶粒,减少了残余元素在晶界的偏聚,并降低了动态再结晶的起始温度,从而改善了试验钢在830~950℃范围内的热塑性。

英文摘要：

In order to investigate the effect of residual elements As,Sn and the improvement of rare earth La on the hot ductility of steels,the tensile tests were carried out on low carbon steel containing some As,Sn and La between 700 ℃ and 1050 ℃ by a Gleeble-1500 thermal simulator. The results show that the segregation of residual elements As and Sn at the grain boundary increase the width and depth of the low ductility region Ⅲ and deteriorate the hot ductility of steels. At the range of 830-950 ℃,the improvement of the hot ductility in the steel by La addition may be attributed to the fixation of La on residual elements,the refinement of grain size,the reduction of the residual elements segregation at the grain boundary and the lowering of the dynamic recrystallization onset temperature.