38CrMoAlA钢回火硬度的变化规律及其函数关系的建立  

Change Rule and Functional Relationship Establishment of Tempering Hardness in 38CrMoAlA Steels

作　　者：郭从盛[1] 龙姝明[2] 冯小明[1] 张会[1] 

机构地区：[1]陕西理工学院材料学院,陕西汉中723003 [2]陕西理工学院物理系,陕西汉中723001

出　　处：《铸造技术》2007年第9期1191-1194,共4页Foundry Technology

基　　金：陕西省自然科学基础研究计划项目(2007E112)

摘　　要：调质钢的回火硬度H与回火温度T和回火时间t存在着函数关系。通过等温回火实验采集了38CrMoAlA钢回火后的硬度数据。这些数据表明,调质钢等温回火时的硬度下降表现为快速下降和缓慢下降两个明显不同的阶段,这一变化规律可以用双指数函数H(T,t)=a(T)e-b(T)t+c(T)e-d(T)t来描述。双指数函数中的参数{a(T),b(T),c(T),d(T)}随温度的变化可以表示成温度的二次多项式函数。通过对实验数据的非线性拟合,可以计算出不同等温条件下参数{a(T),b(T),c(T),d(T)}的取值集合,对取值集合的线性回归分析,可以计算出二次多项式函数中的每一个系数。这些系数与钢的化学成分有关,可称为淬火钢回火时硬度变化的特征系数。There is a functional relationship among tempering hardness H, tempering temperature T and tempering time t in quenched and tempered steels, The hardness data of three kinds of steels were collected by using austempering tests. These data indicate that the tempering hardness change show as two obviously different stages, i.e. fast decrease and slow decrease, during austempering for quenched and tempered steels, This change rule can be described with a double exponential distribution functional relationship. H（T,t） = a（T）e^-b（T）t 4- c（T）e^-d（T）t. The change of parameter {a （T）, b（T）, c（T）, d（T）} with temperature in double exponential function can be expressed as a quadric polynomial function of temperature. The fetching value set of the parameter{a（T）, b（T）, c （T）, d（T）} under different conditions of austempering can be calculated by the nonlinear fitting of the experimental data. The coefficients in quadric polynomial function can be calculated by linear regression analysis of data for the fetching value set. These coefficients relate to the chemical composition of the steels, and can be known as the characteristic coefficient of hardness change of quenched steels during tempering.

关 键 词：调质钢 回火硬度 函数关系 非线性拟合 

分 类 号：TG161[金属学及工艺—热处理]