Impact of Some Selected ARC Welding Variables on the Hardness and Tensile Properties of Steel Welds

The impact of some selected arc welding variables such as welding speed and power input on the hardness and tensile properties of low carbon steel welded joints was studied. Twenty-four (24) samples of the low carbon steel rod with the dimension Ø12mm × 50mm were prepared for each of the two-welding geometry; plane face and double-v edge respectively. Electric arc welding was used for welding each pair of the samples under three selected welding speed and power input to give twelve (12) welded joints for each of the plain face and double-V geometry. Brinell hardness test was carried out on the whole of weldment of welded joints. Tensile test was also carried out to determine the tensile properties of additional set of twelve welded joints for both welding geometries. It was discovered from the study that the hardness of the two shapes considered is higher at medium power input and welding speed of 16.5KW and 12cm/min while it drastically reduces at higher power input and welding speed. Similarly, maximum tensile stress of 827.47MPa and 847.03MPa were obtained for plain face and double-v welded joints respectively at 16.5KW power input and welding speed 12cm/min. The tensile stress reduces with further increase in power input and welding speed. The Young modulus of elasticity of both plane face and double-V edge welded joints increases from the welding speed of 10cm/min to 12cm/min at 16.5KW power input but reduces at higher power input. The results show that arc welding speed and power input have effect on either increasing or reducing the hardness and tensile strength of steel welds.