摘要
对低碳硅锰钢进行了水淬和随后的两相区退火与贝氏体区等温处理,利用光学显微镜、扫描电镜和透射电镜对热处理后试验钢的显微组织进行了观察,采用X射线衍射仪测定了钢中残余奥氏体含量,通过拉伸试验测试了钢的力学性能。结果表明:两相区退火冷却后试验钢的显微组织为铁素体与马氏体,随着两相区退火温度的升高和保温时间的延长,铁素体含量减少,马氏体含量增多,其中铁素体大部分为长条状;经贝氏体区等温处理后,显微组织中的残余奥氏体大部分以板条状存在于贝氏体板条界,极少量以块状存在于先共析铁素体内,其含量随着退火温度的升高和保温时间的延长先增加后降低,在780℃保温5 min时达到最大值;试验钢抗拉强度和屈服强度均随着退火温度升高和保温时间延长单调上升,伸长率在780℃等温5 min时达到最大值。
The water quenched low-carbon Si-Mn steel subsequenty annealed in the two-phase region and isothermal treated in the bainite region. Optical microscopy, scanning electron microscopy and transmission electron microscopy were applied to observe the microstructure of the steel after heat treatment, X-ray diffraction analysis was used to determined the residual austenite content in the steel. The tensile test was performed to deterime the mechanical properties of the steel. The results show that after annealing in two-phase region the microstructure of the steel was ferrite and martensite. With the increase of annealing temperature and holding time, the ferrite content was reduced and martensite content increased. Most of the ferrite were bar-like. After isothermal treatment in the hainite region, the majority of lath-shaped residual austenite existed at the lath bounderies of bainite, farthing existed in the massive proeutectoid ferrite body, and its content increased first and then decrtased with increasing the annealing temperature and holding time, the the maximum content appeared at 780℃ for 5 min. The tensile strength and yield strength of the steel monotenically increased with increasing the annealing temperature and holding time and the elongation reached a maximum value at 780 ℃ for 5 min.
出处
《机械工程材料》
CAS
CSCD
北大核心
2009年第9期85-89,共5页
Materials For Mechanical Engineering
