一种低碳微合金管线钢的热变形行为  

Hot deformation behavior for a kind of low carbon micro-alloy pipeline steel

作　　者：林武[1] 李红英[1] 曾翠婷[1] 宾杰[1] 魏冬冬[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2010年第3期940-947,共8页Journal of Central South University:Science and Technology

基　　金：湖南省科技资助项目(2007CK3072)

摘　　要：采用MMS-200热力模拟实验机进行高温压缩试验,研究一种低碳微合金管线钢在应变速率为0.1,1.0和5.0s-1,变形温度为800～1150℃条件下的热变形行为及流变应力特征,利用透射电镜和光学显微镜观察高温压缩变形后的组织,采用Zener-Hollomon参数的双曲正弦函数来描述实验钢的热变形流变应力行为。研究结果表明:流变应力随着变形温度的升高而降低,随着变形速率的提高而增大;实验钢在高温压缩过程中存在动态回复和动态再结晶2种软化机制,在较高变形温度和较低应变速率条件下,才发生动态再结晶;在获得的流变应力解析式中,结构因子A、应力水平参数α和应力指数n分别为2.6×1018s-1,0.012MPa-1和5.73,热变形激活能为518.73kJ/mol。The hot deformation behavior and flow stress of a low carbon microalloyed pipeline steel were investigated on MMS-200 thermal-mechanical simulating tester. The experimental deformation temperatures varied from 800 ℃ to 1 150 ℃,and deformation rates were from 0.1 s-1 to 5.0 s-1. The microstructures of specimens obtained through high-temperature compressive deformation were observed by transmitted electron microscope and optical microscope. Zener-Hollomon parameters of the hyperbolic sine function were used to describe the high temperature deformation behavior of the flow stress. The results show that the flow stress decreases with the increase of temperature,while increases with the increase of strain rate. There are two kinds of softening mechanisms in thermal deformation process-dynamic recovery and dynamic recrystallization. Dynamic recrystallization occurs under the condition of high temperature and low strain rate. According to the obtained equation of flow stress,parameters A,α and n are 2.6×1018 s-1,0.012 MPa-1 and 5.73,respectively,and the hot deformation activation energy is 518.73 kJ/mol.

关 键 词：低碳微合金钢 热变形 流变应力 动态回复 动态再结晶 

分 类 号：TG146[一般工业技术—材料科学与工程]