鋁合金具有重量輕、強度佳、耐腐蝕性優良及表面美觀等機械應用優點,獲得工業上廣泛的應用;而其中以A356鑄造鋁合金的應用最普遍,尤其是A356鑄造鋁合金製程的改善更是日新月異,如擠壓鑄造和重力鑄造方法等的實際應用。本研究利用A356擠壓和重力的鑄件作為銲接的母材,銲接方法採用氣體鎢極電弧銲,所探討的變數有A356不同的製程及其熱處理、不同的填料、和保護性氣體的流量大小等對銲接品質的影響,對熱處理前後施銲對A356鑄件品質的影響,均做完整的討論。研究結果顯示A356的擠壓鑄件不論用何種填料,均會在熔池產生較多的氣孔數;但經T6熱處理後的A356鑄件經銲接後,則熔池的氣孔數會明顯減少。而所應用的填料則以ER5356或ER5556較明顯地降低熔池的氣孔數量和大小,又在銲接時增加保護性氣體的流量至20 liter/min,對降低熔池的氣孔數亦有相同的效果。
Aluminum alloy has the advantages of light weight, good strength, excellent corrosion resistance and beautiful surface, and has been widely used in industry. Among them, the application of A356 cast aluminum alloy is the most common, especially the improvement of A356 cast aluminum alloy process. It is changing daily, such as the practical application of squeeze casting and gravity casting methods. The squeeze casting and gravity casting of A356 alloy were fused-weld by using gas tungsten arc welding (GTAW) process. The effects of castings and T6 treatment, filler metals and shielding gas flow rates on the qualities of weldments were fully investigated. Experimental results showed that the fusion zone of squeeze casting produced a greater pore number and pore volume than that of gravity casting caused. Use of filler metal (ER5356 or ER5556) significantly decreased the pore number and pore volume comparing the metal ER4043 filler. After T6 treatment, the welded fusion zone was greater than welding as-cast casting. Increasing shielding gas flow rate decreased the pore number and pore volume of fusion zone and in fusion zone could be remarkably improved.