单个冲击对不锈钢管道焊接头低周疲劳寿命的影响

完成了单个冲击对１Ｃｒ１８Ｎｉ９１不锈钢管道焊接头试样低周疲劳寿命影响的试验研究。单个试验最大瞬时峰值应变率达４８０ｓ＾－１。试样未经消除焊接残余应力。采用成组法试验（每组７个试样），对称加载模式，总应变幅为０．００２２８。结果表明，冲击影响受到焊接残余应力和冲击塑性导入机制的耦合作用。焊接残余应力与冲击应力叠加将增加材料损伤，而冲击塑性导入将减缓疲劳损伤和降低疲劳寿命分散性。前者扼制后者。考虑疲

Single Impact Effects on the Low Cycle Fatigue Life of a Stainless Steel Pipe-Welded Joint

An experimental investigation of the single impact effects with high strain rate on the low cycle fatigue life of 1Cr18Ni9Ti stainless steel pipe welded joint was performed A group test ( 7 specimens for each group) was used The joint was made without eliminating the welding residual stress Transient peak strain rate of the test was up to 480 s -1 All fatigue tests were made at total strain amplitude of 0 00228 under fully reversal loading mode The results reveal that the effects are related to a coupling action of the welding residual stress and the impact plastic induced mechanism The welding residual stress, plus impact stress, tends to increase fatigue damage, and in contrast, the impact plasticity induced tends to slow fatigue damage and to decrease the scatter of fatigue life The former checks the later In addition, taking into account the scatter of fatigue lifes a probabilistic assessment approach of the single impact effects is presented and its availability is verified by the statistical analysis of test results