The local yielding behavior in base metal, heat-affected zone, fusion boundary region, and weld metal of low-alloy steel/Alloy 625 filler metal welds was quantified using digital image correlation instrumented cross-weld tensile test. The tested welds exhibited undermatching, matching, or overmatching weld metal yield strength with significant gradients in the local yielding behavior. An undermatching weld yielded at 69 MPa below the base metal yield stress, accumulating to 0.72% total strain. The base metal in an overmatching weld had 110 MPa lower yield strength than the weld metal. The strong strain hardening response in the Alloy 625 weld metal, within the uniform elongation range, and its constraining effect on the fusion boundary region and heat affected zone, led to extensive strain accumulation, necking, and final failure in the base metal of all tested welds. The yielding behavior of the tested welds was compared to stress-based criteria, utilizing minimum specified and as-delivered yield and ultimate tensile strength, and to strain-based criteria. The capability of digital image correlation instrumented cross-weld tensile testing to quantify local yielding and strain accumulation demonstrates potential application in proving conformity to stress-based and strain-based design criteria of dissimilar and matching filler metal welds.

使用数字图像相关仪器交叉焊缝拉伸试验对低合金钢/合金 625 填充金属焊缝的母材金属、热影响区、熔合边界区域和焊缝金属的局部屈服行为进行量化。测试的焊缝表现出不足、匹配或过度匹配的焊缝金属屈服强度，并且局部屈服行为存在显着梯度。欠匹配焊缝在比母材屈服应力低 69 MPa 的压力下屈服，累积总应变为 0.72%。超匹配焊缝中母材的屈服强度比焊缝金属低 110 MPa。合金 625 焊缝金属在均匀伸长率范围内的强烈应变硬化响应及其对熔合边界区域和热影响区的约束作用，导致所有测试的母材中出现广泛的应变积累、颈缩和最终失效焊缝。将测试焊缝的屈服行为与基于应力的标准进行比较，利用最小指定和交付的屈服强度和极限拉伸强度，以及基于应变的标准。数字图像相关仪器交叉焊缝拉伸测试能够量化局部屈服和应变累积，这表明其在证明异种和匹配填充金属焊缝符合基于应力和基于应变的设计标准方面具有潜在的应用价值。