The effects of welding speed on the microstructure and mechanical properties of marine-grade aluminium (AA5754) alloy welded using MIG welding

Abstract

AA5754 aluminium alloys are commonly used in marine and offshore applications as well as in shipbuilding equipment. It is of great importance to weld this alloy in these industrial areas. This study investigated the penetration, microstructure, and mechanical properties of AA5754 Al alloy sheets that were joined using robotic metal inert gas (MIG) welding at different welding speeds. The joints were welded at three welding speeds by keeping the welding current constant, and then macrostructure and microstructure of the samples taken from these joints were examined. Afterward, their hardness, tensile and bending tests were carried out. It was found that the increase in the welding speed decreased the amount of accumulated metal and the penetration rate. Formation of macro-and micro-porosities was observed in the root sections of the weld seams. It appeared that the welding speed increased, the quantity and size of these defects increased, and the mechanical properties were negatively affected by the increase in the welding speed.

Characterization of pulsed-tungsten inert gas (PTIG) welding on AA5754-H111 alloy: mechanical properties and microstructural analysis

“…Macroporous and mesoporous structures formed at the weld seams' foundations. Faster welding speeds exacerbated the problem by reducing the weld quality and negatively impacting the material's mechanical properties [25]. Tests for hardness and tensile strength showed that the material was marginally superior to the base metal.…”

Effects of Surface Roughness on the Diffusion Bonding of 2024 Aluminum Alloy

“…For example, fusion-welded base materials have large deformation and thermal zones, which are prone to cracking [2]. In addition, ceramic materials or high temperature materials cannot be bonded with Al alloys [3], and the resultant porosity is inappropriate for a vacuum chamber material [4]. Fusion welding also has a slow welding speed and high cost [5]; in addition, only butt bonding, and not face-to-face bonding, can be performed, and reactive metals cannot be heterogeneously bonded [6].…”

Tarımsal mekanizasyonda kullanılan 30MnB5 bor çeliğinin kaynak sonrası soğutma rejiminin mekanik ve mikroyapı özelliklerine etkisi

“…MIG kaynak yönteminde argon (Ar), helyum (He) gazları ve farklı oranlarda karışım gazlar (Ar-He, Ar-CO2-O2, Ar-O2 v.s) kullanılabilmektedir. MAG kaynağında ise aktif bir gaz olan CO2 gazı kullanılmaktadır [24][25][26][27][28][29][30][31].…”

“…Dolayısıyla kaynaklı birleştirmelerde ilk aranan özellik birleştirmenin dayanımının ana metal ile aynı veya ona yakın olmasıdır [3,15,[24][25][26][27]. Ancak kaynak işlemi sadece kaynak dikişinin kimyasal bileşimini değiştirmekle kalmaz, aynı zamanda termal döngüye maruz kalan ısıdan etkileyen bölgede bazı metalürjik değişiklikler meydana getirir [28][29][30][31][32]. Bu nedenle kaynak işlemi sonrası kaynak bölgesinin soğuma hızı bağlantıların mekanik ve metalurjik özelliklerini etkileyebilmektedir [26,27,33,34].…”

“…Gazaltı kaynak işlemlerinde koruyucu gazın cinsi kaynak dikişinin mekanik ve metalürjik özellikleri üzerine etki eden en önemli faktörlerden birisidir. Ancak, koruyucu gazlar kaynak işlemi sırasında sıçramalar nedeniyle meydana gelen kayıplar üzerinde de etkilidir [1,28,30,31]. Sıçramalar nedeniyle kaynak bölgesi mekanik yöntemlerle temizlemesi gerektiğinden zaman, enerji ve maddi kayıplara neden olmaktadır[38].Kaynaklı dikiş yüzeylerine yapılan gözle muayene işlemi sonucunda makro enine ve boyuna çatlak, yanma oluğu,…”