轨道车辆材料及其接头强度评估方法对比及优化建议  

Comparison of assessment methods and optimization proposal on railway vehicle material and its joint strength

作　　者：许保磊 赵文平 杜飞 李影 杜建强 王顺 Xu Baolei;Zhao Wenping;Du Fei;Li Ying;Du Jianqiang;Wang Shun(CRRC Tangshan Co.,Ltd.,Tangshan 063035,Hebei,China)

机构地区：[1]唐山机车车辆有限公司,河北唐山063035

出　　处：《焊接》2020年第12期40-47,63,64,共10页Welding & Joining

摘　　要：国内外标准对母材、热影响区、焊缝静强度与疲劳强度评估方法不同,文中对各标准进行了对比。各标准均存在问题,未规定点焊接头的疲劳强度;未提及或未正确规定冷作硬化不锈钢焊接接头的强度;实际焊接接头难以按照疲劳评估标准中的焊接接头清单对号入座;未规定车体与走行部连接位置的疲劳载荷,导致国内外多起车体开裂事故;规定异种金属坡口焊接接头取母材许用应力的较小值,未考虑通常一种焊丝用于所有异种金属焊接的实际情况,全焊缝金属、两侧母材之间强弱关系多样化;未焊透焊缝常按全焊透焊缝评估,角焊缝、塞焊、槽焊只校核对应节点的主应力是否超出焊缝/热影响区的许用应力,不考虑焊缝尺寸、剪应力和附加弯矩。根据项目经验,提出了优化建议。Standards at home and abroad had different assessment methods for static and fatigue strength of base metal,HAZ and weld.The comparison among these standards were conducted in the article.The comparison result indicated that all standards had shortcomings illustrated as followed.There was no regulation on the fatigue strength of spot welded joint.No mention or correct regulation on strength of cold hardening stainless steel welding joint was given.Actual welded joint was hardly able to correlate to the welded joint listed in fatigue assessment standard.There existed no regulation on fatigue load in connection region between running gear and car shell,which resulted in several crack cases of car shell.The smaller allowable stress of dissimilar metals for groove welded joint was adopted.However,no consideration was given to the actual scenario that one sort of welding wire was generally used for all dissimilar metals.Strength ratio between all weld metal and base metal of each side was diversified.Incomplete penetration weld was often regarded as complete penetration weld to assess.For fillet,plug weld and slot weld,only the principal stress of corresponding node was checked whether it exceeded the allowable stress of weld/HAZ or not,but weld size,shear force and additional bending moment were left out.The optimization proposal was put forward pursuant to project experience.

关 键 词：母材 热影响区 焊缝 静强度 疲劳 

分 类 号：TG407[金属学及工艺—焊接]