Analytical Modeling of Temperature Distribution, Peak Temperature, Cooling Rate and Thermal Cycles in a Solid Work Piece Welded by Laser Welding Process

Abstract

Generalized theoretical prediction of temperature distribution, peak temperature, cooling rate and thermal cycles in a solid work piece welded by laser welding process, where no melting is occurs, i.e., from the boundary of fusion zone to the end of heat affected zone. With the moving point or line heat source may be considered for the analysis that indicates the temperature gradient ahead of the heat source is much higher than that behind, increasing welding velocity elongates the isotherms surrounding the heat source, higher thermal conductivity of materials make the isotherm more circular, reducing the temperature gradient in front of the heat source. The peak temperature experienced throughout the workpiece, determine the size of the heat affected zone (HAZ). The peak temperature at a given point is experienced by the point shortly after it is passed by the heat source. The size of the HAZ increases with the net energy input. The cooling rates experienced by a material, determines the grain structure and phases that are formed. Increasing the heat input reduces the cooling rate. While increasing the welding velocity increases the cooling rate. Higher thickness, thermal conductivity of the material also increases the cooling rate.