Effect of Grain Size Deformation on Laser Processed Sheet Steel under High Temperature
Laser material processing is a novel technique employed to process and deform plates and sheets metals such as
steels, aluminium, magnesium and titanium, with the uniqueness of high thermal expansion coefficient. This technique has
large applications in shipbuilding, automotive and aerospace industries. Laser beam forming is a rapid heating and cooling
process that evolve with unique microstructures at different processing conditions. However, processing at high temperature
may be desirable depending on the application and ability to control the process. The crystal structure of low carbon steel is a
body-centered cubic (BCC) structure whereby little percentage carbon content can dissolve in ferrite at room temperature.
Upon heating, the Body Centre Cubic (BCC) ferrite transforms to Face Centre Cubic (FCC) austenite at 912oC. These crystal
structures impart different properties to the steel material. Improving the strength and mechanical properties of materials i s
achieved by processing it to bring about the desired deformation and further refine the grain structures. The heat treatment
processes improve the strength further. This study report on the effects of grain sizes on the deformation of laser formed
sheet steel. The result revealed that the grain sizes measured at the LBF sample 24 were refined at about 38% when
compared with the parent material while a grain refinement of 2% for LBF sample 9.
Index Terms - Deformation, Grain size, Laser Material Processing and Microstructure.