Study of Heat Source Model and Residual Stress Caused by Welding in GMAW of Al Alloy

Abstract

An important trend in recent ships and offshore structures is that they require high strength as well as light weight. Due to this trend, various materials are being used to replace existing carbon steel, with aluminum alloys being used frequently. In particular, this trend is conspicuous in outfitting rather than in traditional structural strength members. As a typical example, the use of aluminum alloys is increasing in helideck structures and handrails, which are tertiary components. In order to make the example structures above, welding is absolutely necessary. There are various welding methods used for aluminum alloy, with gas metal arc welding (GMAW) the most widely used. It is very important to be able to simulate welding and to predict various physical quantities of this welding technique in the production of aluminum alloy structures. In particular, welding-induced residual stresses are always generated in a structure that has been welded, and can greatly influence structural stability. Therefore, this paper proposes a method to simulate the welding phenomenon using a precise welding heat source for various aluminum alloys. Additionally, the validity of the proposed finite element (FE) analysis method is verified by measuring the residual stress of the representative aluminum alloy.

Keywords

• aluminum alloy
• GMAW (gas metal arc welding)
• residual stress
• FEA (finite element analysis)
• hole drilling method