Calculation of Fusion Zone Size in the Submerged-Arc Hardfacing of Rolling-Mill Rolls

Results are presented from calculation of the dimensions of the fusion zone in the hardfacing of rollingmill rolls by a composite strip electrode. The calculation is performed on the basis of the solution of a differential equation of heat conduction that accounts for the temperature dependence of the thermophysical properties of the material comprising the rolls. Heat propagation in a semi-infinite body undergoing hardfacing is modeled by the finite-element method. The values calculated for the depth of fusion agree well with the experimental data. The calculated results are used to determine the effect of the parameters of the composite electrode on the formation of the weld pool and the conditions necessary to obtain a macroscopically heterogeneous composition with a prescribed hardness distribution across the hardfaced bead (weld). The uneven wear being exhibited by such a heterogeneous hardfaced layer formed on the work roll of a roughing scale-breaker in a wide-strip hot-rolling mill is making it easier to remove scale from the surface of the rolled product.