The truck assembly used in the mining industry involves a considerable amount of welding applications, where the materials that have to be joined differ in metallurgical and mechanical properties. The complexity in the analysis of these joints increases when the welding is developed on large thickness plates, in which are necessary to apply a controlled sequence of welding beads (multi pass welding). This paper presents an analysis by finite element method of the evolution in the thermal history, microstructure and strain produced by a multipass Gas Metal arc welding process, applied to the welded joint of Hardox 400 and ASTM 514 plates. Besides this a comparison between the analytical results and experimental data was made, and it was found that this method can be efficiently used to accurately determine appropriate welding parameters of such components.