Effects of bubble expansion on wear of refractory for BOF stirring plugs embedding tuyeres

Single tuyere wear tests of MgO-C and burnt magnesia bricks were performed to study relations between tuyere characteristics and refractory wear parameters, with emphasis on the wear zone geometry. Either Ar or N-2 was used as injected gas and the test temperature for liquid metal was 1400, 1550 and 1700 degrees C. A bubble expansion wear mechanism was proposed for the mechanical wear of tuyere refractory by comparison of bubble radii and the wear zone geometry of refractory bricks and H3BO3 disks. Equations are derived to predict the deep and shear wear zone radii and the refractory wear rate at values of the nominal Mach number up to one. These equations can be used for an optimum design of single- and multiple-tuyere plugs for combined blowing BOF, as well as for optimization of gas stirring operation to reduce the wear of MgO-C refractory around the tuyere and for the plugs.