重载传动齿轮钢淬透性及相变变形规律的研究

发布时间：2018-03-12 07:04

  本文选题：齿轮钢　切入点：化学成分　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：本论文以20Cr2Ni4重载传动齿轮钢为研究对象,主要采用顶端淬透性、热膨胀、力学性能及渗碳变形等实验,研究了化学成分波动对其淬透性、相变组织、力学性能及渗碳热处理变形的影响规律,可得出以下结论:淬透性实验表明,碳元素对实验钢淬透性的影响最大,随着碳含量增加,硬度值增加,淬透性增大,淬透性曲线开始下降点向右移动;合金元素对淬透性的影响主要是通过对端淬特性值Eb的影响来实现,随着合金元素含量增加,淬透性曲线拐点位置右移。考虑合金元素交互作用而获得的适用于实验钢种的淬透性预报模型具有较高的精度。过冷奥氏体连续冷却转变实验结果表明,随着碳元素和合金元素含量的增加,CCT曲线右移,马氏体转变区域增大,贝氏体转变右移,珠光体转变区域消失。马氏体转变的临界冷却速度约为4.3 ℃/s;在冷却速度降低到0.86 ℃/s时,开始出现少量针状贝氏体,当冷却速度增大时以贝氏体/马氏体复相组织为主。渗碳热处理变形实验结果表明,随着C、Cr、Ni元素含量的增加,渗碳热处理变形增大,其中以C元素的影响最大。淬透性和马氏体转变点是影响渗碳热处理变形的主要因素,即随着淬透性的提高和Ms点的降低,渗碳热处理变形量和变形率均增大。
[Abstract]:In this paper, 20Cr2Ni4 heavy-duty transmission gear steel is used as the research object. The hardenability, thermal expansion, mechanical properties and Carburizing deformation of 20Cr2Ni4 heavy-duty transmission gear steel are studied, and the hardenability and phase transformation structure of 20Cr2Ni4 heavy duty transmission gear steel are studied. The effects of mechanical properties and Carburizing heat treatment deformation on the hardenability of experimental steel are as follows: the hardenability experiment shows that the hardenability of experimental steel is most affected by carbon element. With the increase of carbon content, hardness increases and hardenability increases. The hardenability curve began to move to the right, and the effect of alloy elements on hardenability was mainly realized by the effect of end quenching characteristic value E _ b, with the increase of alloy element content. The hardenability curve inflection point is shifted to the right. The prediction model for hardenability of experimental steels, which takes account of the interaction of alloying elements, has a high accuracy. The experimental results of continuous cooling transformation of undercooled austenite show that the model can be used to predict the hardenability of experimental steels. With the increase of carbon element and alloy element content, the CCT curve shifts to the right, the martensite transformation region increases, and the bainite transformation shifts to the right. The critical cooling rate of martensite transformation is about 4.3 鈩，

本文编号：1600489