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Journal : Journal of Energy, Mechanical, Material and Manufacturing Engineering

The Effect of Argon Flow Rate on Mechanical Properties and Microstructures in Titanium Welding Dewi Puspita Sari; Amir Arifin; Gunawan Gunawan; Dendy Adanta; Ihsan Asura; Imam Syofii
JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol. 6 No. 3 (2021): In Progress
Publisher : University of Muhammadiyah Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22219/jemmme.v6i3.19082

Abstract

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.
Application of Computational Fluid Dynamics Method for Cross-flow Turbine in Pico Scale Imam Syofi'i; Dendy Adanta; Aji Putro Prakoso; Dewi Puspita Sari
JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol. 6 No. 1 (2021)
Publisher : University of Muhammadiyah Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22219/jemmme.v6i1.12813

Abstract

Crisis electricity was a crucial issue in the rural area. Crossflow turbine (CFT) in pico in pico scale is the best option for electricity provider for rural areas. Due to its usefulness and development of computer technology, computational fluid dynamics method application for CFT study becomes increasingly frequent. This paper compiles the implementation of the computational fluid dynamic (CFD) approach for CFT on a pico scale. Based on the literature, the Renormalization Group (RNG)  turbulence model is recommended to predict the flow field that occurs in CFT because its error is lower than others turbulence models, the RNG  error of 3.08%, standard  of 3.19%, and transitional SST of 3.10%. Furthermore, six-degrees of freedom (6-DoF) is recommended because it has an error of 3.1% than a moving mesh of 9.5% for the unsteady approach. Thus, based on the review, the RNG  turbulence model and 6-DoF are recommended for the CFT on the pico scale.