Evaluating the Impact Toughness of Mild Steel Welded Joint Using Taguchi Method in Automated Shielded Metal Arc Welding

Abstract

The impact toughness is commonly used in industrial and manufacturing fields for testing of materials properties. The impact toughness is also known as the Charpy V-notch testing which emphasis systematized of strain rate test and its influences over energy observed from the specimen during fracture. In this research, the mild steel (AISI 1080) used to weld for impact toughness (Charpy V-notch testing). The mild steel has a good mechanical property and low cost so it's commonly used in the manufacturing and welding processing fields. Due to the critical issue of welding quality and welding speed accuracy, the electrode E6013 was used to filler metal on the specimens by automated based shielded metal arc welding (ABSMAW) which also can improve welding quality and reduce welding errors. In this study parameters set up with speed (range from 3.19 to 4.6 mm/sec) using the different range of angle and electrode diameter (range from 45° to 60°, and 2.6 mm, 3.2 mm, 4.0 mm) also configuration of the welding specimen was clamped in the butt joint of double grooving which allows automatic based shielded metal arc welded to took place. The welding specimens were cut according to Charpy V-notch testing requirement with the ASTM E23 standard, the V-notch point was considered in the welded pool and heat-affected zone (HAZ), the specimens were ground properly while the Taguchi method used to analyze responses data from the experimental testing. The experiment found a direct relationship between welding angle, impact strength, and absorbed energy that the welding angle increases, the impact strength and absorbed energy increases; the welding speed is also the most effective factor in this testing. In this study also found the toughness of the welded pool is much lower than the toughness of HAZ. The optimum values are produced through the welding speed of 3.19 mm/sec, welding angle of 50° and electrode diameter of 2.6 mm.