近年來，各國政府積極發展再生能源，以達成淨零碳排之目標。其中，氫能源被視為最具發展潛力的能源之一，因此加氫站之建設亦日益普及。然而，由於加氫站管路設計複雜，管路間多以焊接方式進行材料接合。已有眾多研究指出，焊接過程中會瞬間導入大量熱能，使材料快速熔化並迅速凝固以完成接合；此過程將導致材料內部顯微組織產生劇烈變化，例如晶粒成長、相變化及殘留應力導入等。上述變化可能使尺寸極小的氫原子更容易由焊接區域擴散進入材料內部，並與金屬原子產生交互作用，進而大幅降低材料延展性，導致管路在非預期情況下發生破壞，此現象即稱為氫脆。
為改善氫脆對材料性能之影響，本研究採用雷射電弧混合焊接技術對316L不鏽鋼進行接合，並利用田口法品質工程設計焊接參數，包括電弧功率、雷射功率及兩熱源之夾角。接著觀察不同參數條件下所對應之顯微組織特徵，包括肥粒鐵含量、肥粒鐵連通度及熱影響區寬度，以建立焊接參數與顯微組織之關聯性。最終，將試片加工為中空試棒，並於材料內部通入200 bar之氮氣及氫氣進行慢速拉伸測試，以評估顯微組織與抗氫脆能力之關聯性。
研究結果顯示，肥粒鐵含量與肥粒鐵連通度主要受電弧功率控制；相較之下，熱影響區寬度則主要受到雷射功率及參數間交互作用之影響。此外，根據慢速拉伸測試結果及其對應之顯微組織分析可知，當焊接材料具有較高之肥粒鐵含量、肥粒鐵連通度及較寬之熱影響區時，其於氫氣環境中的延伸率與斷面截縮率下降幅度較大，表示材料抵抗氫脆之能力較差。

Hydrogen energy is a promising low-carbon energy carrier, and welded SUS316L stainless steel pipelines are commonly used in hydrogen-related systems. However, welding can change the microstructure of materials and affect their hydrogen embrittlement resistance. In this study, laser-arc hybrid welding was applied to SUS316L stainless steel, and the effects of MIG power, laser power, and the angle between the two heat sources were investigated using the Taguchi method. The results showed that δ-ferrite content and ferrite connectivity were mainly affected by MIG power, while the heat-affected zone width was mainly influenced by laser power and parameter interactions. Slow strain rate tests under 200 bar nitrogen and hydrogen atmospheres showed that hydrogen caused a decrease in elongation and reduction of area, especially in specimens with higher ferrite content, higher ferrite connectivity, and a wider heat-affected zone. Fracture surface observations also indicated that hydrogen mainly affected the region near the inner wall of the hollow specimen. Overall, higher δ-ferrite content, higher ferrite connectivity, and a wider heat-affected zone reduced the hydrogen embrittlement resistance of welded SUS316L stainless steel.

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