Experimental Investigation of Electro-Discharge Machining Characteristics of Welded Joints of Aisi 1541h

Abstract

The demand for precision machining in high-strength materials has led to increased interest in understanding the electro-discharge machining (EDM) behavior of welded joints in industrial applications. This study explores the effects of key EDM parameters, such as electrode material, peak current, and pulse duration, on AISI 1541H welded joints. It evaluates the material removal rate (MRR), tool wear rate (TWR), surface roughness (SR), and microstructure, revealing important correlations between EDM settings and the quality of machined surfaces. The study investigates the machining characteristics of oxy-acetylene gas (OAG) and tungsten-inert gas (TIG) welded samples across the fusion zone (FZ), heat-affected zone (HAZ), and unaffected zone (UAZ). For the OAG-welded sample, MRR in the FZ was 15.077[Formula: see text]mg/min which is less than the MRR of HAZ, and UAZ. It was fine-grain structure has a high MRR in comparison to Coarse grain. Whereas, TWR was 0.22[Formula: see text]mg/min, 0.32[Formula: see text]mg/min, and 0.185[Formula: see text]mg/min in the FZ, HAZ and UAZ respectively. SR values were found Lowest in UAZ at 7.11[Formula: see text][Formula: see text]m, and SR was reported at 8.33[Formula: see text][Formula: see text]m in FZ, and 7.32[Formula: see text][Formula: see text]m in HAZ. Measured microhardness values were 196 HV0.5 in FZ which is 6.2% higher than the microhardness of HAZ. Similar trends were observed in the TIG welded sample, where the MRR was 17.113[Formula: see text]mg/min (FZ), 17.436[Formula: see text]mg/min (HAZ), and 17.811[Formula: see text]mg/min in UAZ. The study reveals that TIG-welded joints outperform OAG joints in terms of machining performance, material removal rates (MRRs), hardness, and surface finish due to lower porosity and better grain distribution whereas the OAG process shows microporosity due to shielding limitations.