Abstract
This paper reports the influencing factors and the characteristic behaviour
of steel plates during both the mechanical forming and laser beam forming
processes. Samples of the steel sheets were mechanically bent to 120 mm
curvatures using a 20 ton capacity eccentric mechanical press at room temperature
and also with the laser beam using a 4.4 kW Nd: YAG laser system
at a scan speed of 1.9 m/min, beam diameter of 12 mm, laser power of
1.7 kW at 25% beam overlap using argon for cooling the irradiated surfaces.
The chemical composition of both the as-received material and the
formed samples were analysed by emission spectroscopy to quantify the
changes in the elemental composition. The result shows a percentage
increase in the carbon after the mechanical and laser forming processes
when compared to the parent material. This can be attributed to the
enhancement resulting from the forming processes. The formed samples
were further characterized through microstructure, microhardness and tensile
tests. The microstructural characterisation of the samples revealed that
the grains of the mechanically formed and laser formed components are
elongated, it was also observed that there is an increase in the pearlite
grains of the laser formed components resulting from the thermal heating
during the laser process. The microhardness profiles of the formed components
showed that there is a significant percentage increase in the Vickers
microhardness values of the laser formed samples when compared to the
mechanically formed samples and with respect to the parent material. The
laser beam forming process can be considered a more appropriate forming
process in terms of the resulting material properties in this regard.