In the past of developing technology, the need for welding techniques to connect the structures of the component is increasing, especially tungsten inert gas (TIG). Several factors are considered in selecting material to be welded: toughness, density, and corrosion resistance. Titanium is a metal with a low density, has good heat transfer, and high melting point hence widely used for various purposes, such as petrochemicals, spacecraft, medical devices, and reactors. However, the titanium welding process is difficult because no absence of protection against air during the welding process results in high absorption of oxygen from free air (which causes carbon and hydrogen contamination). As a result, the mechanical properties quality of commercially pure titanium decreases. The main parameters of TIG welding to overcome high absorption of oxygen are arc length, welding current, welding travel speed, and flow rate of shielding gas (argon). For this case, this study investigates the effect of argon flow rate on mechanical properties and microstructures in titanium welding. Based on the results, the argon flow rate significantly affects the welding results; a high argon flow rate protects the welding from oxygen so that the hardness is not too high increased compared to low flow rates. Furthermore, it increases the hardness and decreases the strength of the material and ductility when fractured. Based on metallographic testing, the main metal area of commercially pure titanium has a uniform grain size with a hexagonal closed packed (HCP) phase. In contrast, the grain forms become elongated like straw, called platelet and acicular alpha in the HAZ and weld metal.
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