R350硬头轨离线热处理工艺试验

Process experiment of off-line heat treatment of R350 hardhead rail

用60D40特种断面钢轨制造道岔尖轨,我国过去的制造技术路线是:先机加工轨头变截面,后对轨头感应热处理。实践表明,尖轨轨头工作边平直度很难达到客运专线道岔制造验收暂行技术条件,且生产效率较低。为使其制造路线改造为轨头先热处理后机加工,对60D40钢轨进行了R350硬头轨离线热处理工艺的近百次试验。试验结果表明,表面硬度、断面硬度分布、拉伸性能和显微组织各项质量指标均达到了BS EN 13674-2:2006中R350HT硬头轨欧洲标准的技术要求。本试验为我国道岔制造技术的提升并与国外标准接轨打下了基础。

The traditional manufacturing procedure to make switch rail of 60D40 special cross section rail includes two processes, first is to machine the variable-section of railhead, and then to induction hardening. Production practice shows that the straightness of gauge side of the switch rail still attain with difficulty the acceptance requirements of the Tentative Specification for Manufacturing of Turnouts for Passenger Dedicated Lines, and in the meantime the production efficient is low. In order to reform the existing turnout switch rail manufacturing technology, i.e. to arrange the machining process after heat treatment, experimental study and nearly one hundred times of trials were implemented to determine the off-line heat treatment process for R350 hard head rail of 601）40 rail. Experimental results show that the surface hardness, cross hardness profile, tensile strength and microstructure all meet the technical requirements of the hard head rail of R350HT of the European standards BS EN 13674-2： 2006. This technology lays the foundation for upgrading and being in line with international standards of China＇s turnouts manufacture technology.