Reducing production scrap is vital for decarbonizing the aluminum industry. In extrusion, the greatest source of scrap stems from removing profile sections containing transverse (charge) welds that are deemed too weak for their intended purpose. However, until now, there has been no predictive transverse weld strength model. This article establishes a transverse weld strength model as a function of billet properties and extrusion parameters. It extends the film theory of solid-state welding by enhancing Cooper and Allwood's plane strain model to consider non-plane strain deformations at the billet-billet interface. These enhancements are informed by analyzing oxide fragmentation patterns through shear lag modeling and microscopy of profiles extruded from anodized billets. Model predictions are assessed through shear tests on welds from single and two-piece billets, extruded into rod, bar, and multi-hollow profiles. The experiments reveal that negative surface expansions at the weld nose cause interface buckling and weaker welds, but both surface expansions and weld strengths increase with distance from the nose. In non-axisymmetric profiles, deformation conditions and strengths vary across, as well as along, the weld. Two-piece billet welds are longer but reach bulk strength long before weld termination. The model predicts these trends and shows that die pressures are sufficient for micro-extrusion of any exposed substrate through interface oxide cracks. This underscores the significance of interface strains in exposing substrate and determining the weld strength. The model can help increase process yields by determining minimum lengths of weak profile to scrap and aiding process optimization for increased weld strength.

减少生产废料对于铝工业脱碳至关重要。在挤压过程中，废品的最大来源是去除含有横向（充电）焊缝的型材部分，这些焊缝被认为对于其预期目的而言太弱。然而，到目前为止，还没有预测横向焊缝强度的模型。本文建立了一个横向焊缝强度模型，作为坯料特性和挤压参数的函数。它通过增强 Cooper 和 Allwood 的平面应变模型来考虑钢坯-钢坯界面处的非平面应变变形，从而扩展了固态焊接的薄膜理论。这些增强功能是通过剪切滞后模型和阳极氧化坯料挤压型材的显微镜分析氧化物碎片模式来实现的。模型预测是通过对单件和两件式钢坯的焊缝进行剪切测试来评估的，这些钢坯被挤压成棒材、棒材和多层空心型材。实验表明，焊头处的负表面膨胀会导致界面屈曲和焊缝变弱，但表面膨胀和焊缝强度都会随着距焊头的距离而增加。在非轴对称型材中，变形条件和强度在焊缝上和沿焊缝上各不相同。两件式钢坯焊缝较长，但在焊接终止之前很久就达到了整体强度。该模型预测了这些趋势，并表明模具压力足以通过界面氧化物裂纹对任何暴露的基材进行微挤压。这强调了界面应变在暴露基材和确定焊接强度方面的重要性。该模型可以通过确定要报废的弱型材的最小长度并帮助优化工艺以提高焊接强度来帮助提高工艺产量。