Determining the modes of layerwise laser welding of corrosion-resistant steel plates

Abstract

Background. One of the main features of layerwise laser welding of metals and metal alloys is that as a result of intense energy exposure, a relatively fast heating of a relatively thin surface layer occurs, leading to a change in the physical and mechanical state of the surface. The theoretical and experimental studies of the simulation of the effect of additive laser mechanics in a corrosion-resistant plate have revealed sinusoidal, rectangular, sawtooth forms of temperature cycles of laser mechanics. The purpose of the study is to establish the patterns of formation of temperature fields in plates of corrosion steel during layerwise laser welding, to determine recommendations for the appointment of rational process modes. Materials and methods. Analytical methods for studying thermal stresses in plates were used, digital models for the distribution of temperature fields over the surface and along the depth of the part were built. The results are verified experimentally by metallographic pilot studies. Results. The performed analysis made it possible to consider that the most frequently implemented temperature cycles in layerwise laser welding are sinusoidal, rectangular and sawtooth. Methods have been developed for calculating the temperature field in the plates under any form of temperature effect on the surface of the plate in the quasistationary mode of heat transfer and with an asymmetric cycle of temperature fluctuations. It has been established that for any form of the temperature cycle, the temperature of the plate surface depends on the oscillation frequency. Conclusions. In layerwise laser welding, the heating of metal parts by a laser can take place in sinusoidal, rectangular, sawtooth cycles with the same duration of the cooling period and the heating period. The limits of change in thermal stresses on the surface of the part depend significantly on the specific type of temperature cycle of the medium.

Keywords

• layerwise laser welding
• stainless steel
• plate
• temperature
• temperature cycle shapes