预热时间对钢轨铝热焊焊缝组织和力学性能的影响  

Microstructural and Mechanical Characterization of Thermite Weld in Rails at Different Preheating Processing Parameters

作　　者：张伟娜[1] 林哲[1] 谭毅[1] 

机构地区：[1]大连理工大学三束材料改性国家重点实验室材料科学与工程学院,辽宁大连116024

出　　处：《机械工程材料》2008年第4期16-19,76,共5页Materials For Mechanical Engineering

摘　　要：对铝热焊接不同预热时间(5.5,4.5,3.5,2.5 min)下PD3钢轨焊缝的显微组织、力学性能和断裂机制等进行了研究。结果表明:在上述预热工艺下铝热焊缝处的组织均为铁素体和珠光体,焊缝中心处的硬度最低,缩短预热时间硬度值稍有提高,随着离开焊缝中心距离的增加硬度值提高,热影响区靠近焊缝处硬度较大,向母材一侧逐渐降低;焊缝处轨头部位的抗拉强度最高,轨脚次之,轨腰部位最低;随着预热时间的增加,bσ和0σ.2略有下降,但对塑性影响不大;拉伸断口均为解理断口,显示脆性断裂。In order to reduce the operation time for thermite welding repair of the railway line,an improved preheating technology to reduce preheating time was developed.The microstructure,hardness,mechanical properties and fracture mechanism of thermite welded rail steel joints treated at different preheating times(2.5,3.5,4.5,and 5.5 min) were studied.It has been found that the microstructure of steel joints which were preheated for the above mentioned times was all fine ferrite-pearlite.The hardness at the center ...

关 键 词：铝热焊接 PD3钢 显微组织 力学性能 断裂机制 

分 类 号：TG407[金属学及工艺—焊接]