5052-H32鋁合金電阻點銲拉剪強度之韋伯可靠度分析

Abstract

5052-H32鋁合金因其耐候性及適當的強度，應用於汽車的車殼鈑金，有其發展的有利條件。另外，臺灣的3C產業(電腦、通訊、消費性電子產品)蓬勃發展，5052-H32有重量輕、強度適當、不影響通訊及不導磁等特性，在應用的領域倍受青睞。 本研究所使用的5052-H32鋁合金是屬於鋁-鎂合金（商用材），經過加工硬化及穩定處理，強度等級中等，配合單相交流點銲機實施點銲(50KVA)，經由不同的製程參數，找出點銲相對最佳製程參數。在相對最佳製程參數條件下，經由拉伸試驗，探討母材的拉剪力強度分佈，再藉由韋伯可靠度分析，討論該製程的可靠度。 經研究發現，厚度1.0mm的5052-H32鋁合金之最佳製程參數為銲接電流17.1KＡ，電極加壓力130kgf，通電時間為13cycles、17cycles、21cycles。此外，由銲核微觀組織與微硬度試驗得知，銲核附近組織分成母材、熱影響區及重熔凝固區，母材的微硬度值最大，重熔區的微硬度值次之，而熱影響區的微硬度值最小。 將點銲試片作拉剪強度之可靠度分析，其中韋伯二參數之m值介於2.45與10.96之間，由於可靠度韋伯模數大於1，屬於磨耗型破壞，證明使用50KVA單相交流點銲機點銲接合5052-H32鋁合金有其適用性。5052-H32 aluminum alloys, with the effects of resisting weather and its proper intensity, has the advantage of applying to the outside plate of cars. Besides, due to the prosperous development of 3C(computer, communication, consumptive electronic product) in Taiwan, 5052-H32 aluminum alloys have the qualities of light weight, proper intensity, not affecting communication and not conducting magnetic, so it is noticed in the applicative field. 5052-H32 aluminum alloys, used in the research, is aluminum- magnesium alloys. Through processing hardness and steady treatment, its intensity is medium, matching the AC spot welding machine . In the best welding parameter, by the test of tensile-sheer strength ,we studied the rang of tensile-sheer strength, and then by analyzing reliability , we discussed the reliability of welding parameter. After studying, we discovered that the best welding parameter of 1.0mm’s 5052-H32 aluminum alloy is 17.1KA welding current, 130kgf electrode force, 13cycles, 17cycles, 21cycles holding time. In addition, from the micro-structure of nugget and the test of micro-hardness, the structure around nugget is divided into base material, heat-affected zone(HAZ) and re-melted zone. The micro-hardness value of base material is the largest, the micro-hardness value of re-melted zone is the second, and the micro-hardness value of HAZ is the smallest. The Weibull modulus, m, of the welding plate which is used to test the intensity of tensile-shear strength is between 2.45 and 10.96. Under all conditions, Weibull modulus, m, is over 1 and it’s wear-out mode destruction, which proves that it is practical to use 50KVA AC spot welding machine to welded 5052-H32 aluminum alloys.