Laser powder bed fusion (LPBF), an important additive manufacturing (AM) technique, has received a great deal of research attention and industrial application. The capability to fabricate complicated shapes and structures enables this technique to be applied for the manufacturing of rapid prototypes and complex parts. In operation, the constant melting and cooling of metal powders in a layer-by-layer fashion leads to large gradients and a rapid evolution of temperature, which may cause considerable residual stress and deformation. Polymer electrolyte membrane (PEM) fuel cells are a major type of fuel cells that operate under low temperature with high efficiency. PEM fuel cell components must be free of major distortion to avoid leakage of the reactant gases, intrusion of contaminants, and a large interfacial resistance. In this study, a three-dimensional (3D) numerical study is conducted to investigate the residual stress and deformation in a fuel cell inlet/outlet fitting directly built on the bipolar plate by LPBF. Both Inconel 718 (IN718) and stainless steel 316 L (SS316L) are used as the building materials. The distortion prifle predictions are compered with literature data. Additionally, the validated tool is employed to investigate several major parameters in LPBF fabrication to assess their impacts on distortion, including laser power, laser speed, and layer thickness. In our case, the laser power and speed have a significant impact on the distortion of the inlet/outlet fitting. SS316L shows a much less distortion (about 40 µm) than that of IN71 (about 90 µm) for the maximum distortion and a nearly 30% smaller average distortion at all measuring locations. The middle height of the fitting is subject to the largest distortion. A strain parameter ${\epsilon }^{*}$ is discussed to facilitate the analysis of the simulation results.

激光粉末床融合（LPBF）是一种重要的增材制造（AM）技术，受到了大量的研究关注和工业应用。制造复杂形状和结构的能力使该技术能够应用于制造快速原型和复杂零件。在操作中，金属粉末以逐层方式不断熔化和冷却会导致大的梯度和温度的快速演变，这可能会导致相当大的残余应力和变形。聚合物电解质膜 (PEM) 燃料电池是一种主要类型的燃料电池，可在低温下高效运行。PEM 燃料电池组件必须没有重大变形，以避免反应气体泄漏、污染物侵入和大的界面电阻。在这项研究中，进行三维 (3D) 数值研究以研究由 LPBF 直接构建在双极板上的燃料电池入口/出口配件中的残余应力和变形。Inconel 718 (IN718) 和不锈钢 316 L (SS316L) 均用作建筑材料。失真轮廓预测与文献数据相比较。此外，经过验证的工具用于研究 LPBF 制造中的几个主要参数，以评估它们对失真的影响，包括激光功率、激光速度和层厚度。在我们的案例中，激光功率和速度对入口/出口配件的变形有重大影响。SS316L 的最大失真（约 90 µm）比 IN71 的失真（约 40 µm）小得多，所有测量位置的平均失真小近 30%。配件的中间高度受制于最大的变形。应变参数${\epsilon }^{*}$ 讨论以方便分析模拟结果。