Effect of high-energy laser welding parameters on the microstructure and mechanical properties of 304 stainless steel
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Date
2021
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Abstract
Autogenous bead-on-plate laser welding was performed on 2 mm 304SS materials at different heatinputs. The influence of laser energy in low welding speeds on weld performance using a Nd:YAG laserwas studied. The weld performance was characterized in terms of weld bead morphology,microstructure and mechanical properties. The result revealed that the crater increased with theincrease of heat input, so there is a linear relationship between crater and heat input. The gradualincrease of the heat input was not directly related to the penetration of the weld bead. At the highestheat input, weld beads considerably expanded and also the crater deepened, the hardness increasedin these joints while tensile strength and ductility reduced. The best mechanical properties wereobtained with high laser energy at intermediate heat input. These weldments exhibited betterstrength even better than base metal 304SS. The microhardness values were distributedhomogeneously from the fusion zone to the base metal. Laser energy increased the ferrite networkand brought finer ferrites. As a result, usable laser welding parameters in terms of good strength, aswell as good ductility and weld bead morphology were defined for welding 304 SS with 2 mmthickness.