Fast crystallization of structural steel during laser processing of the surface

The size, shape, and structure of the molten zone appearing on the surface of Fe-C multicomponent alloy upon laser recrystallization are studied. The laser scan rate varies between 0.01 to 0.167 m/s. A set of equations for the temperature and concentration fields is derived within a model of locally nonequilibrium crystallization. The use of the hypothesis for marginal stability, as applied to crystal growth, makes it possible to find the characteristic size of the crystal structure. The mathematical simulation of recrystallization upon laser processing is in good agreement with experimental data. The results of the simulation can be used for predicting the mechanical properties in the molten zone as a function of the energy parameters of the radiation and thermophysical properties of the alloy.