热冲压硼钢非等温奥氏体相变动力学模型  

Kinetics model of non-isothermal austenite phase transformation for hot stamping boron steel

作　　者：李学涛[1,2] 江社明[1] 张启富[1] 滕华湘[2] 赵海峰 黄鸣东 

机构地区：[1]钢铁研究总院先进金属材料涂镀国家工程实验室,北京100081 [2]首钢技术研究院薄板所,北京100043 [3]北京科技大学机械工程学院,北京100083

出　　处：《钢铁》2017年第8期92-96,共5页Iron and Steel

基　　金：北京市科技计划资助项目(D15110300350000)

摘　　要：利用Gleeble-3500热模拟试验机对热冲压硼钢进行了线膨胀试验,得到了不同加热速度下硼钢奥氏体化动力学曲线;研究了加热速度对相变过程的影响,结果显示,加热速度越高,获得相同体积分数的奥氏体所需的时间越短,且奥氏体开始转变温度升高,当加热温度介于Ac1和Ac3时,奥氏体体积分数转变速度随着加热温度的升高先增大后减小。根据奥氏体形核长大理论,考虑加热速度的影响,建立了非等温条件下热冲压硼钢的统一奥氏体相变动力学模型。利用遗传算法确定并优化了硼钢奥氏体化动力学模型中的材料常数,所得材料常数确定的相变模型能够较好的描述硼钢连续加热过程线膨胀曲线,并能够较好地预测硼钢在不同加热速度下的奥氏体体积分数。The austenite transformation kinetics curves of hot stamping boron steel were investigated by thermal expan- sion testing on a Gleeble-3500 themml-mechanical simulator under different heating rates. The effect of heating rate on the austenite formation was investigated. Results show that the austenite formation start temperature rises with heating rate increasing, to achieve the same volume fraction of austenite, and less time is required at a higher heating rate. When the heating temperature is between Ao~ and At3, transformation rate of austenite percentage with the heating temper- ature rising will first increase then decrease. A unified kinetics model of the non-isothermal austenitization considering the influence of heating rate, based on the theory of austenite nucleation and growth, was established. Material con- stants in the kinetics model were determined and optimized through a genetic algorithm in Matlab. The model can de- scribe the austenite transformation kinetics curves of boron steel and accurately predict the fraction of the austenite under different heating rates.

关 键 词：硼钢 奥氏体 相变动力学模型 加热速度 遗传算法 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG306[金属学及工艺—金属材料]