API X52焊管管母及其焊接接头的疲劳裂纹扩展速率

Fatigue Crack Growth Rates of The Parent and Welded Metals for API X52 Welded Line Pipe

对两种 X52管线钢管母及其焊接接头的疲劳裂纹扩展速率进行了测试 ,发现两种焊管管母虽有 50 MPa以上强度差 ,但几乎有相同的疲劳裂纹扩展速率。而且 ,两种焊管焊缝及热影响区的疲劳裂纹扩展速率均低于管母 ,但在排除焊接残余应力导致的裂纹闭合效应后 。

In the present work fatigue crack growth rates of the parent and welded metals for two kinds of API X52 welded line pipes have been measured.It is found that the two kinds of parents have almost the same fatigue crack growth rates,even there is more than 50 MPa difference between strength of the two parents.Moreover,the fatigue crack growth rates of the weld metal and heat affected zone are lower than those of the parents for the two line pipes.Having excluded effect of welding residual stresses on crack closure,fatigue crack growth rates of the welded joints are equivalent to the parents for the two line pipes.