Nb-B复合高强度集装箱用钢的高温变形行为

来源期刊：金属学报2011年第1期

论文作者：宋仁伯 张永坤 文新理 贾翼速

文章页码：34 - 40

关键词：Nb-B钢； 真应力-真应变曲线； 应变硬化指数； 动态再结晶； 激活能

Key words：Nb-B steel； true stress-true strain curve； strain hardening exponent； dynamic recrystallization； activation energy

摘    要：在Gleeble-1500热模拟试验机上,通过单道次高温压缩变形实验,研究Nb-B复合高强度集装箱用钢的高温变形行为.结果表明:在本实验所采用的变形工艺参数范围内,实验钢在热加工硬化过程中,当应变速率为0.1和1 s^-1时,应变硬化指数n与真应变ε曲线上出现"单波峰"和"单波谷";应变速率为5和15 s^-1时,应变硬化指数n与真应变ε曲线上出现"双波峰"和"双波谷"现象,在热加工硬化过程中的硬化机制以位错强化、孪晶强化和析出强化为主.根据Zener-Hollomon和Ludwik方程,对实验数据进行非线性拟合,得出在1123-1423 K范围内的变形激活能和应力指数分别为(428.188±20.109)kJ/mol和4.923,并建立了Z参数的表达式、热变形方程、动态再结晶的模型图.

Abstract: Hot deformation behaviors of high strength container steel compounded with Nb-B have been systematically studied through high temperature compression tests on the Gleeble-1500 thermal-mechanical simulator. In the present deformation conditions, there are different relationships between the strain hardening exponent (n) and the true strain (ε) under different strain rates at the deformation temperature of 1423 K; n-εcurves have single peak and single valley at the strain rates of 0.1 s^-1 and 1s^-1, while n-εcurves have double peaks and double valleys at the strain rates of 5 s^-1 and 15 s^-1.During the heat work-hardening process, dislocation strengthening, twin strengthening and precipitation strengthening are the major work-hardening mechanisms of the tested steel. According to Zener-Hollomon and Ludwik equation, the experimental data have been regressed by using nonlinear method, the apparent deformation activation energy (Q) and stress exponent (n) were obtained to be about (428.188±20.109) kJ/mol and 4.923 in the temperature range of 1123 K-1423 K, respectively. Finally, an expression of Z parameter, hot deformation equation and dynamic recrystallization model diagram of the tested steel are established.