MODELING OF THERMAL PROCESSES IN THE SURFACE LAYER OF STAINLESS CHROMIUM-NICKEL STEEL DURING LASER PULSED ALLOYING

10.25712/ASTU.1811-1416.2022.02.013

Abstract

The paper describes the results of a graphical representation and numerical simulation of the process of laser alloying of stainless chromium-nickel steel 12Cr18Ni10Ti with a preliminary applied alloying coating of graphite paste. As a result of the simulation, a problem was solved, the purpose of which was to determine the technological feasibility of the required heating of the stainless steel surface and the diffusion of alloying mixture elements in an extended range of pulse energy (0.08-1.34 J). Modeling has confirmed the possibility of the formation of a modified surface layer and a heat-affected zone (diffusion layer) characterized by structural changes as a result of laser pulsed alloying. The Elcut 5.1 software package was used to solve the problem of non-stationary heat transfer for calculating the transient and steady-state temperature field, taking into account the heat exchange of the elements of the “environment-coating-sample” system. The relevance was represented by such characteristics as the temperature distribution over time, the temperature gradient and heat flux in the zone of interaction of laser radiation and a layer of graphite coating. The modeling performed helped to determine the dependence of the depth, temperature and heating time of the surface layer of the samples on the modes of pulsed radiation. In particular, the curves of the dependence of the heating of the steel surface over the cross section of the sample at different depths on the time of exposure to a single laser pulse are plotted. The data obtained are necessary to build a more accurate plan for the experimental study, since allow to exclude irrational modes of laser processing, leading to excessive melting and overburning of the treated surface, or, conversely, which are ineffective for the course of thermal diffusion processes.