Porthole die extrusion is used to produce complex hollow aluminum cross-sections for automotive applications. In a porthole die, the material is first divided into multiple streams which are separated by a bridge, before rejoining in the weld chamber and finally passing through the die orifice. The rejoining of the material in the weld chamber produces lines known as weld lines in the final extruded product. The microstructure along the weld line and its associated quality are strongly influenced by the thermal-mechanical history the material experiences as it passes through the portholes, the weld chamber, and the die orifice, which can be altered by die design and, in particular, the bridge geometry. To study the influence of bridge geometry on weld line microstructure and final quality, a series of porthole die extrusion experiments was conducted using an Al–Mg–Si–Mn–Cr alloy and two different types of bridge geometry (streamlined and flat). The experimental results showed that bridge geometry had a significant effect on the local microstructure and crystallographic texture at the weld line. Specifically, EBSD analysis indicated that the weld line texture associated with a streamlined bridge geometry consisted of a deformation texture (mainly the copper component), while the local texture produced by a flat bridge was a recrystallization texture consisting of Cube, Goss, and Cube_RD texture components. Simulation of the extrusion process, using DEFORM 3D, indicated that the weld line produced using a flat bridge experienced a slightly higher temperature, but much higher equivalent strains than the streamlined case. Material away from the weld line was very similar for both cases, indicating that the effect of the die bridge geometry is localized to the region close to the weld line.

孔口模具挤压用于生产用于汽车应用的复杂中空铝截面。在舷窗模具中，材料首先被分成多股流，这些流被桥隔开，然后在焊接室中重新汇合，最后通过模口。焊接室中材料的重新连接会在最终挤压产品中产生称为焊接线的线。沿焊缝的微观结构及其相关质量受到材料在通过舷窗、焊接室和模具孔时所经历的热机械历史的强烈影响，这些热机械历史可以通过模具设计而改变，特别是，桥梁几何。研究桥梁几何形状对熔接线微观结构和最终质量的影响，使用 Al-Mg-Si-Mn-Cr 合金和两种不同类型的桥几何结构（流线型和扁平型）进行了一系列舷窗模具挤压实验。实验结果表明，桥的几何形状对熔接线处的局部微观结构和晶体织构有显着影响。具体而言，EBSD 分析表明，与流线型桥梁几何形状相关的熔接线纹理由变形纹理（主要是铜成分）组成，而扁平桥产生的局部纹理是由 Cube、Goss 和 Cube 组成的再结晶纹理。_RD纹理组件。使用 DEFORM 3D 对挤出过程进行模拟表明，使用平桥产生的熔接线经历了略高的温度，但比流线型情况下的等效应变高得多。两种情况下远离熔接线的材料非常相似，表明模桥几何形状的影响仅限于靠近熔接线的区域。