微合金化钢轨淬火工艺的优化及其疲劳裂纹扩展行为研究  

Optimization of Quenching Process and Fatigue Crack Growth Behavior of Microalloyed Rail

作　　者：陈林[1] 戴宇恒 崔健伟 周庆飞 岑耀东[1] CHEN Lin;DAI Yuheng;CUI Jianwei;ZHOU Qingfei;CEN Yaodong(School of Material and Metallurgy,Inner Mongolia University of Science&Technology,Baotou 014010;Inner Mongolia First Machinery Group Corporation,Baotou 014032)

机构地区：[1]内蒙古科技大学材料与冶金学院,包头014010 [2]内蒙古第一机械集团有限公司,包头014032

出　　处：《机械工程学报》2022年第14期233-240,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51361021);内蒙古自治区科技重大专项(ZDZX2018024);内蒙古自然科学基金(2019LH05016);内蒙古自治区高等学校科学技术研究(NJZY20089);内蒙古科技大学创新基金(2019QDL-B06)资助项目。

摘　　要：为定量化分析微合金化与淬火工艺、裂纹扩展的关联性,寻找修正钢轨淬火时所产生自回火现象的方法,通过对GGX-G重轨钢和自行开发设计的微合金元素重轨试验钢在8℃/s淬火冷速与8℃/s淬火冷速自回火后展开疲劳裂纹扩展试验,结果表明:未热处理态下,试验钢疲劳寿命优于GGX-G钢11万次;在经8℃/s冷速及8℃/s冷速自回火工艺后,由77万次均提升至107万次,自回火未影响试验钢的疲劳寿命,仍有良好的疲劳性能;淬火后试验钢在Ⅱ区均出现的慢速扩展区,且自回火后试验钢的?K范围更高,微合金化后的钢轨对自回火所造成的疲劳性能降低有着优良的抗性;淬火工艺后的试验钢均优于国标要求,且8℃/s淬火冷速与8℃/s淬火冷速自回火的疲劳断口未见差异,同样表明自回火对试验钢的综合疲劳性能影响甚微,有着良好的抗自回火能力。通过向钢轨中添加一定的微合金元素,不仅提升了淬火后钢轨的疲劳性能,同时也修正了自回火对钢轨性能的影响。In order to quantitative analysis of the correlation between microalloying with quenching process and crack growth,to find a way to correct the phenomenon of self-tempering during rail quenching,through the fatigue crack growth test of GGX-G heavy rail steel and self-developed and designed microalloyed element heavy rail experimental steel after quenching and cooling rate of 8 ℃/s and quenching and cooling rate of 8 ℃/s and self-tempering,the results show that under the condition of no heat treatment,the fatigue life of the experimental steel is better than that of GGX-G steel for 0.11 million times;after 8 ℃/s cold speed and 8 ℃/s cold speed self-tempering process,it has been increased from 0.77 million times to 1.07 million times,and self-tempering does not affect the fatigue life of the steel,and still has good fatigue performance;after quenching,there is a slow propagation zone in zone II of the experimental steel,and the ?K range of the experimental steel is higher after self-tempering,the microalloyed rail has excellent resistance to the reduction of fatigue properties caused by self-tempering;the experimental steels after quenching process all meet the requirements of national standard,and the fatigue fracture surface of 8 ℃/s quenching cooling rate is similar to that of 8 ℃/s quenching cooling rate,which also indicates that self-tempering has little effect on fatigue properties of experimental steels,it has strong self-tempering resistance.The addition of microalloyed elements not only improves the fatigue performance of quenched rail,but also corrects the effect of self-tempering on rail performance.

关 键 词：合金元素 重轨钢 淬火工艺 自回火 裂纹扩展 

分 类 号：TG142[一般工业技术—材料科学与工程]