The aim of this paper is to highlight a method for improving laser beam efficiency. The laser weld bead profile depends on various parameters such as beam power, welding speed, wavelength of the laser radiation or the initial temperature of the material. Taking into account that laser beam welding efficiency is usually limited by synchronization of the laser source parameters, new methods were developed. In this paper is analyzed the influence of preheating the material and of the wavelength of laser radiation on the laser weld bead profile. Improvement in penetration depth was noted for preheating the material to around 140°C.