不同參數對AA7003鋁合金銲接氣孔率與機械性質之研究

Abstract

本文主要探討在鋁合金對接下尋找最佳銲接參數及適當填料。在不同參數下，調整不同之電流、床台速度及輸送銲線速度，使造成各種不同的銲件效果。本研究著重於7003同種鋁材之銲接與熱處理中高強度鋁合金為實驗的材料，利用變頻式氬銲機，施以惰性氣體鎢極電弧銲(Gas Tunsten Arc Welding)進行不開槽填料銲接，填料選用ER4043及ER5356兩種銲線直徑均為1.6mm。 實驗項目包括拉伸測試、微硬度量測、金相顯微鏡組織觀察、電子顯微鏡(SEM)之破斷面的表面型態。作為今後探討鋁合金銲接後對母材及銲道之影響。實驗結果顯示：使用適當的預熱能使鋁合金7003之銲件，降低熱裂的生成，適當的銲後熱處理，能有效的提升銲道和熱影響區的強度，而氣孔的含量，脈衝電流銲接一般比連續電流銲接來的少。增加Zn的溶入量，能增強銲件的最大抗拉強度。

The purpose of this investigation was to determine the optimum welding conditions and filler metal。The optimal post welding treatment for the dissimilar base metal was also evaluated。The 7003 aluminum alloy was used in this research. The Gas Tunsten Arc Welding process was used with filler metals of ER4043 and ER5356.The wire diameter was 。 Tensile test，microhardness test，optical metallographic examination，and SEM were conducted 。 The experimental results showed that hot cracking can be reduced in 7003 aluminum alloy welds made with suitable preheat。 The proper post weld heat treatment can effectively increase the strength in fusion zone and HAZ。 Precipitation in grain boundary and grain interior can cause hot cracking in 7003 aluminum alloy weld。The porosity content of the pulsed weld is in general found to be comparatively lower than that of the continuous regular weld。The increase in zinc pickup in fusion zone can enhances the ultimate tensile strength of the weldment。