Effect of Welding Current on the Mechanical and Microstructural Characteristics of Low-Carbon Steel Welds for Truck Bodybuilding

Heavy-duty trucks have become essential in most industries nowadays, such as goods
transportation, oil and gas, mining, and delivery of bulk commodities to urban centers.
Truck body designs always depend on the nature of the loads to be transported, road
conditions, and distance coverage. Thus, after selecting the right materials, Welding
plays a pivotal role in assembling truck components, and selecting appropriate welding
parameters is essential for ensuring structural integrity and performance. This study
examines the effect of shielded metal arc welding (SMAW) current on the mechanical
and microstructural properties of welded joints, focusing on impact strength, tensile
strength, yield strength, and elongation. Welding currents ranging from 50 A to 100 A
were tested to assess material behavior under different conditions. Results indicate that
welding current significantly influences mechanical properties. The highest impact
strength was achieved at 90 A, showing increased toughness with higher current. The
maximum tensile and yield strengths occurred at 60 A, suggesting that moderate current
yields stronger welds. Elongation, reflecting ductility, also peaked at 60 A, indicating
an optimal balance between strength and flexibility. Microstructural analysis revealed
that higher currents (90A) caused coarser grains in the weld zone, enhancing toughness
but potentially reducing strength. At 60 A, finer grains were observed, contributing to
greater tensile and yield strength. These findings highlight the dual influence of
welding current on both mechanical performance and microstructural characteristics of
the weld.