含焊接缺陷的30CrMnSiNi2A钢焊接件的疲劳寿命估算

本文分析了焊接缺陷对超高强度钢３０ＣｒＭｎＳｉＮｉ２Ａ焊接件疲劳寿命的影响，给出了定理评估含焊接缺陷的焊接件疲劳性能的方法，焊接缺陷可分成类裂纹型和非裂纹型两类，前者的作用与裂纹相当，含这类缺陷的焊接件寿命近似等于裂纹扩展寿命；后者的作用则类似缺口，含这类缺陷的焊接件寿命为裂纹起始与扩展寿命之和，裂纹扩展寿命可用断裂力学的方法计算，始裂寿命则可用材料的始裂寿命公式计算，但在计算中要考虑表面状态修正

Fatigue life prediction for butt welds of 30CrMnSiNi2A steel containing welding delect

This paper investigates the ,effect of welding defect on fatigue life of buttwelds of an ultra high strength steel(30CrMnSiNi2A) and gives a quantitative ap-proach to evaluate fatigue resistance of the butt welds containing welding defect. Theresults indicate that the welding detect can be devided into two kinds. the crack-likedefect and noncrack-like defect, The former plays a role as a crack and the total lifeof a welded joint with it is approximate to the crack propagation life,ie, the time ofcrack propagation from the initial defect size to a critical one to induce final fracture.The latter, however, can be taken as a notch and the life of the butt weld containingit is the sum of the fatigue crack initiation(FCI)life and the fatigue crack propagation(FCP) life . The FCI Iife can be predicted by using the FCI life expression determinedfrom notch specimens of material, but modification should be made to take account ofthe difference surface conditions of the notched specimen and the real FCI location inthe welded joint. The FCP life can be estimated by using fracture mechanics approach.Finally, several methods to approve the fatigue resistance of butt welds are proposed.