不同焊接特征对管线钢与法兰焊接接头疲劳寿命影响  

Effect of different welding feature on the fatigue life of pipeline steel and flange welded joint

作　　者：刘鑫[1] 刘紫微 LIU Xin;LIU Ziwei(China Petroleum Pipeline Engineering Corporation,Langfang 065000,Hebei,China)

机构地区：[1]中国石油天然气管道工程有限公司,河北廊坊065000

出　　处：《焊接》2025年第4期91-96,共6页Welding & Joining

摘　　要：【目的】旨在研究满焊、不满焊和延伸焊3种焊接特征对管线钢和法兰等效T形接头疲劳寿命的影响。【方法】建立3种焊接特征有限元模型,并采用高频疲劳试验机,验证仿真结果的准确性。【结果】结果表明,管线钢和法兰等效T形接头焊缝处的整体应变能密度变化趋势为先减小,达到峰谷后,再逐渐增大,最小网格尺寸选用峰谷位置,为5.5 mm。随外应力的增加,疲劳次数逐渐减小,断裂现象均发生在收弧位置,试验结果和仿真结果疲劳S-N曲线一致。在应力为60 kN时,最大误差控制在13.3%。采用仿真手段可有效减少试验样本数量,预测疲劳循环次数。【结论】在存活率50%的S-N曲线和循环周次为2×106的疲劳强度时,未满焊焊接接头疲劳强度比满焊焊接特征高1.3%,比延伸焊焊接特征高5.6%;未满焊焊接接头的疲劳寿命比满焊和延伸焊接头的疲劳寿命都高。[Objective]The aim is study the influence of three welding features,full welding,incomplete welding and extended welding,on the fatigue life of pipeline steel and flange equivalent T-joints.[Methods]Three kinds of welding feature finite element models are established,and the accuracy of the simulation results is verified by a high frequency fatigue testing machine.[Results]The results show that the overall strain energy density change trend at the weld of the pipeline steel and flange equivalent T-joint is to decrease first,then gradually increase after reaching the peak valley.The minimum grid size is selected at the peak and valley positions,which is 5.5 mm.With the increase of the external stress,the number of fatigue gradually decreases,and the fracture position occurs at the position of the arc termination.The fatigue S-N curve of the test results and the simulation results is consistent.The maximum error is controlled within 13.3%at the stress of 60 kN.The use of simulation methods can effectively reduce the number of test samples and predict the number of fatigue cycles.[Conclusion]At the survival 6 rate of 50%S-N curve and the fatigue strength of 2×10 cycles,the fatigue strength of incomplete welding feature is 1.3%higher than that of the full welding feature,and 5.6%higher than that of the extended welding feature.The fatigue life of the incomplete welding feature is higher than that of the full welding feature and the extended welding feature.

关 键 词：焊接特征 疲劳寿命 T形接头 S-N曲线 

分 类 号：TG406[金属学及工艺—焊接]