The article deals with the analysis and subsequent simulation of a heterogeneous butt weld joint. Specifically, it is a combination of S355 steel and AlSI316 anti-corrosion steel. The welding simulation was based on a real experiment, during which several quantities were measured and analyzed, which served to define the boundary conditions for the simulation. The result of the analysis is the calculation of temperature fields and deformations for a heterogeneous joint, as well as monitoring the influence of different steels on the welding process and heat propagation.