PSI - Issue 33

Rizki Dwi Ardika et al. / Procedia Structural Integrity 33 (2021) 171–180 Author name / Structural Integrity Procedia 00 (2019) 000–000

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1. Introduction Along with the times, steel and iron materials are rarely used and are starting to change to aluminum. Aluminum has been widely used in automotive, railroad, and marine engines because of its low density, high strength, and good corrosion resistance (Golumbfskie et al., 2016)(Chenxiao Zhu et al., 2017). In the marine shipbuilding process, aluminum is the main component widely used because it has excellent corrosion resistance (Jain et al., 2013)(Lim et al., 2016). The aluminum alloy used for shipping applications is aluminum 5083, with the primary alloy being magnesium (Seong-Jong et al., 2013)(Abdulstaar et al., 2014). Aluminum 5083 is widely used in the manufacture of naval ferries and vessels (Balasubramanian et al., 2008). One of the manufacturing and connection processes on marine vessels is using welding techniques. Welding is one of the commonly used metal joining techniques by joining metals by creating coalescence due to heat (Olabode et al., 2013). The widely used aluminum welding process is by using GMAW. GMAW is an electric arc welding process using shielding in the form of inert gases such as argon and helium, and electrodes used are rolled to be used continuously without the need to replace electrodes (Ribeiro et al., 2020). In addition to using GMAW, welding in ship structures also uses GTAW. The number of joining processes using welding techniques due to low cost, relatively fast implementation, and good mechanical properties (Heidarzadeh et al., 2020). Several problems are often found in the aluminum welding process, such as unstable arc welding, distortion, porosity, excessive welding spatter and softening in the heat-affected zone (HAZ) (Ramaswamy et al., 2020). However, a welding defect that often arises in aluminum alloys is porosity (Lin et al., 2017). The result of cracked weld joints is usually caused by porosity. The formation of porosity in aluminum alloys is caused by the solubility of hydrogen (Brůna & Sládek, 2011). Hydrogen can come from the base metal, environment, and air (H. Yu et al., 2015). The aluminum welding environment's effect on porosity is influenced by temperature, hydrogen, humidity, and wind speed. The solubility of hydrogen will increase with increasing temperature, especially when aluminum melting. In welding, there is melting, and that's when a lot of hydrogen gas trapped on the weld metal (Y. Han et al., 2019). Temperature determines the result of welding so that a suitable temperature can produce good welding. Cracks in the weld are caused by the low-temperature environment around the weld (Zheng et al., 2018). Defects of porosity in welding can reduce toughness, reduce fatigue, reduce ductility in welded joints and cause changes in the microstructure, causing changes in the mechanical properties of welding results (Tjaronge et al., 2015). Based on the above explanation, a comprehensive discussion of the effect of porosity on welding is critical. Research on the impact of porosity on welded joints is still limited, and the discussion's focus is very diverse. To become a comprehensive and easily understood material, a review of this article was carried out. This review is expected to be a reference in mapping the development of research on the effect of porosity in welding, making it easier for researchers to know the formation, environmental effects, impacts, and ways to overcome porosity in welded joints.

Nomenclature HAZ

heat-affected zone GTAW gas tungsten arc welding GMAW gas metal arc welding CMT cold metal transfer MIG metal inert gas TIG tungsten inert gas