田口實驗法應用於不銹鋼交流點銲參數優化

Application of Taguchi Experiment Method in Parameter Optimization of Alternating Current Spot Welding of Stainless Steel

本研究選擇電極夾持力、點銲電流、點銲時間及保持時間等交流點銲製程參數，先以田口實驗探討此參數對316L 不銹鋼接頭拉剪負荷影響，接續針對點銲電流進行品質提升實驗獲致最大接頭拉剪負荷，最後探討最佳化參數組合對316L 不銹鋼銲核冶金性質影響。實驗結果顯示點銲電流對接頭拉剪負荷最具顯著影響性。本研究依田口實驗獲致之最佳化參數組合具95%信賴水準。品質提升實驗獲致之接頭拉剪負荷較田口實驗提高12.85%。綜合田口實驗與品質提升實驗得知當採用3 kN 電極夾持力、7.3 kA 點銲電流、15 cycles 電極擠壓時間、15 cycles 點銲時間及7 cycles 保持時間等製程參數時，將獲致316L不銹鋼交流點銲最大接頭拉剪負荷。另因316L 不銹鋼銲核存在d肥粒鐵，故可獲較母材高之硬度值。

This study employed the Taguchi experiment to investigate the influenceof process parameters (electrode force, welding current, weldingtime, and hold time) of alternating current (AC) spot welding on thetensile-shear load of the 316L stainless steel joint. A quality improvementexperiment assisted by welding current was used to determine an optimalprocess parameter for increasing the tensile-shear load of the joint. Theinfluences of an optimal process parameter on the metallurgical propertiesof the 316L stainless steel nugget were also investigated. The resultsshow that welding current has the greatest influence on the joint tensile-shearload. According to Taguchi method statistics, an optimal combination of design parameters shows a 95% confidence level. Comparison of resultsobtained by using the Taguchi experiment, the quality improvementexperiment can result in a 12.85% increase in the joint tensile-shear load.Based on the results of this study, an optimal parameter combination of3 kN electrode force, 7.3 kA welding current, 15 cycles squeeze time, 15cycles welding time, and 7 cycles hold time give the highest joint tensileshearload for AC spot welding of 316L stainless steel. Compared withthe 316L stainless steel base metal, the nugget exhibits delta ferrite in anaustenite matrix, resulting in a higher hardness.