<p>Forming sheet metals by a moving heat source (i.e., line heating) is an efficient and economical method of forming metal sheets into desired shapes, including curvatures, which nowadays needs to replace convenient mechanical forming processes. However, only a few studies have been carried out on deforming steel sheets into a required shape by using an oxy-acetylene gas torch as a heat source using a numerical finite element model. This is mainly due to the difficulty of numerically modeling the amount of heat flux from the gas torch to the sheet metal, temperature distribution on the surface of the sheet, deformation resulting from different amounts of heat, analyzing the effect of the heat path, and experimentally maintaining the surface temperature of the sheet metal on a given path. Due to these difficulties, there is a weakness in judgment of where and how much to heat the material to obtain the required shape of the sheets. In this study for different amounts of heat flux from a gas torch to the surface of thin mild steel sheets, the temperature distribution on the surface of thin mild steel sheets is numerically modeled by 3D FEM software called ANSYS, and experimentally the surface temperature is controlled by a professional infrared thermometer on thin mild steel sheets of size 200 × 200 × 4&#xa0;mm for straight, rectangular, and parallel path line heating to determine where and how much to heat the sheet to deform into desired shapes. Finally, the numerical and experimental results are compared, and the results obtained were fairly acceptable with the error less than 5–7% and in good agreement.</p>