Kinetics of the WC particles motion in liquid steel during laser surface modification*

Abstract

ABSTRACT Laser surface modification of steel with tungsten carbide (WC) particles provides significant wear-resistance increasing. At the same time, it is important to achieve a uniform distribution of reinforcing particles over the depth of the created composite layer. To find out the possibility of the particles of different sizes application and to determine the allowable ranges of parameters of the coaxial to the laser beam powder injection, the calculations of the kinetics of penetration of WC particles into the molten surface of a sample made of carbon steel were carried out. It was shown that WC spherical particles with a diameter of about 50–150 µm, which are the most suitable for this application, could be injected into the entire depth of the molten part of the steel matrix if their speed of movement from the nozzle edge is from 6 m/s. All of them must reach the boundaries of the molten pool, and its shape determines their distribution throughout the depth. This provides the possibility to achieve uniform hardening throughout the depth by varying the parameters of laser radiation.