LANCE FOR BOTTOM BLOWING OF METAL WITH GASES IN LADLE AND METHOD OF LANCE MANUFACTURE Russian patent published in 2002 - IPC

FIELD: metallurgy; applicable in ladle treatment of steel with blown gases. SUBSTANCE: lance includes metal sleeve with bottom filed with refractory body in which longitudinal through slot channels are formed. Formed in sleeve lower part, between refractory body and bottom is gap, at least, 5 mm in size, communicating the longitudinal channels with cavity of gas-supplying tube. Gap is made with overlapping the inlet if channels by not in excess of 2 mm. Width of channels in direction of gas flow is determined by relationship B=Bo+tgα H, where B is current width of through channels varying according to lance height; Bo is inlet width of through channels; H is current height of lance; α is angle of channel opening, α≥ 0.5 deg. Method of lance manufacture includes manufacture of conical sleeve with bottom and gas- supplying tube, installation of channel-forming strips for formation of longitudinal through slot channels, laying by layers and vibration packing of refractory concrete body with subsequent heat treatment. Installed and secured to bottom part of sleeve center is expandable template made of multiply plywood or of some other easily burning material for locking lower channel-forming strips. Strips are locked by recesses sawn in expandable template. For locking of upper ends of channel- forming strips, fitted from outside onto conical sleeve upper part is lock in form of conical ring which has supporting sockets above sleeve bottom by ribbon of woven cotton materials. Ribbon is passed through hole in center of expandable template. Ribbon upper end is tied into knot larger than hole in template. Ribbon lower end is passed and secured to tube by screws screwed into template. Then, ribbon is tightened, wound round screws and tied by knots. EFFECT: reduced consumption of energy in lance operation, reduced resistance to blowing and higher quality of lance manufacture. 3 cl, 3 dwg, 2 tbl