高温合金电子束焊接头缺口疲劳寿命预测

Fatigue life prediction of electron beam welding joint of superalloy

为了研究GH4169电子束焊接头缺口疲劳寿命预测方法,设计并开展了其缺口件的疲劳试验,基于临界距离理论,提出了适用于不同缺口形状的电子束焊接头疲劳寿命预测方法。通过试验,获得了GH4169电子束焊接头U型、V-1型及V-2型3种缺口件的名义应力-寿命曲线。基于V-2型缺口件试验结果,提出了一种临界距离的反推方法,确定了GH4169电子束焊接头缺口件的特征尺寸。据此,分别采用临界距离点法和线法对缺口件疲劳寿命预测。结果表明:临界距离点法对文中缺口件的适应性更好。进一步分析发现,对于不同缺口形状,当其理论应力集中系数相近时,采用相同的特征尺寸可以获得较好的寿命预测结果,均在2倍分散带以内。

In order to study the prediction method of notch fatigue life of GH4169 electron beam welded joints,the fatigue tests of notched specimens were designed and carried out.Based on the critical distance theory,the fatigue life prediction method for different notch shapes of electron beam welded joints was proposed.The nominal stress-life curves of three notched specimens of GH4169 electron beam welded joints(U type,V-1 type and V-2 type)were obtained through tests.Based on the test results of V-2 notched parts,an inverse method of critical distance was proposed to determine the characteristic dimensions of GH4169 electron beam welding notched joints.The fatigue life of notched joints was predicted by the critical distance point method and the line method,respectively.The results showed that the critical distance point method had better adaptability to the notched joints.Further analysis showed that for different notch shapes,when the theoretical stress concentration coefficients were similar,better life prediction results can be obtained by using the same characteristic size in the double dispersion zone.