摘要
利用Gleeble 3500型热模拟实验机,测定了GCr15钢共析转变温度区间。通过扫描电镜和硬度测试,研究了奥氏体化温度和时间对碳化物颗粒形态及分布的影响,分析了GCr15钢共析转变过程中的显微组织变化及其影响因素。结果表明:GCr15钢不完全奥氏体化,有助于离异共析转变的发生。在共析转变温度区间存在一临界点,从共析转变开始点到该临界点,GCr15钢共析转变的主要方式为离异共析转变,直接形成球状珠光体组织;从临界点到共析转变结束点,共析转变过程中出现片状珠光体,在此区间内,随温度的下降,片状珠光体转变逐渐趋于主导。利用离异共析转变,GCr15钢可直接获得完全的球状珠光体组织,碳化物平均尺寸为1. 35μm,布氏硬度为181 HBW左右,球化时间可缩短到6.5 h。
Eutectoid transformation temperature interval of GCr15 steel was determined by the Gleeble 3500 heat simulation experiment machine. The effects of austenitizing temperature and time on the morphology of particles of GCr15 steel heating in the box-type furnace were investigated by means of SEM and hardness testing,and the microstructure change and its influence factors in the process of eutectoid transformation of GCr15 steel were analyzed. The results show that it is helpful for the divorced eutectic transformation of GCr15 steel when it is incompletely austenitized. There is a critical point between eutectoid transformation temperature ranges. From the eutectoid transformation staring point to the critical one as cooling,the divorced eutectoid transformation of GCr15 steel is dominant,which produces the spheroidal pearlite directly during the transformation. From the critical point to the end one of eutectoid transformation finishing,the laminar pearlite can be observed during the eutectoid transformation process. And with the decrease of temperature,the transformation of the laminar pearlite gradually tended to dominate. GCr15 steel can directly obtain the complete spherical pearlitic microstructure by using the divorce eutectoid transformation. The average size of the spherical carbide is about 1. 35 μm,the hardness is about 181 HBW. As well as the spherification time can be shortened to 6.5 h.
作者
尹志新
徐荧
梁均全
陈俊霖
李进飞
Yin Zhixin;Xu Ying;Liang Junquan;Chen Junlin;Li Jinfei(College of Resources, Environment and Materials,Guangxi University, Nanning Guangxi 530004,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2019年第3期11-16,共6页
Heat Treatment of Metals
基金
国家自然科学基金(51661001)
关键词
轴承钢
离异共析转变
临界点
碳化物
bearing steel
divorced eutectoid transformation
critical point
carbide
