| 摘要 |
A lance for blowing oxygen from above into a ladle of an iron foundry has a nozzle head with at least four main tuyeres of larger diameter and as many ancillary tuyeres of smaller diameter, the larger tuyeres serving to blow into the melt for decarburizing the metal while the smaller ones promote afterburning of the evolving carbon monoxide just above the melt surface. The axes of the main tuyeres are inclined to the nozzle-head axis at an angle of about 14 DEG to 17 DEG while the axes of the ancillary tuyeres have an angle of inclination exceeding that of the main tuyeres by about 30 DEG to 50 DEG . In order to slow down the air flow through the ancillary tuyeres with reference to the surface-penetrating jets of the main tuyeres, the former are provided with inner peripheral inlays or grooves of annular or helicoidal shape. |
