Abstract: A dart has a metal bar 1 passing through a ceramic, shaped, dart head 2 and then through a cylindrical ceramic dart stem 3. A sleeve 4 of a carbonaceous or reactive material is provided about the stem 3 or a layer of that material can be formed on the lower face 5 of the dart head 2 (at the interface of the steel and slag). A block or sleeve 6 of suitable reactive material could be positioned on the top face 7 of the dart. The reactive material could be cardboard or paper, or a reactive metal, such as aluminum or magnesium. In each case a chemical reaction with the molten steel will result in an updraft in the steel which clears slag from the area of the tap hole.

Abstract: An insert 6 is pushed into an eroded tap hole 5 of a steel-making vessel. This insert has outer and inner plates 7 and 8 formed from relatively thin steel sheet or cardboard which will flex so as to adapt itself to the internal dimensions of the tap hole 5 as shown. Between the two plates 7 and 8 there is a tubular support member 9 defining a central passage-way 10 which has holes 11 formed on its side walls which communicate with the open volume 12 between the end plates 7 and 8. A supply hose 13 is connected to the tubular member 10, through which a settable material comprising a clay and binder in wet form is injected so that the whole volume between the end plates 7 and 8 is filled. At the temperatures experienced the clay material will set rapidly so as to block off the tap hole 5.

Abstract: A plug 4 fitted in the side wall of a steel-making vessel is sealed in place by a crushed refractory material 8. This tends to burn off after a number of pourings of molten steel to create an enlarged approach well. This well can be repaired by inserting a steel pipe 10 having a tapered portion 12 leading to a narrow entry portion 11 so as to seal off the tap hole 5 in the plug 4. The well can then be filled with a refractory material 14 which sinters or fuses with heat to effect the repair. The steel pipe 10 will burn off during a subsequent heating and pouring of molten steel.

Abstract: A cavity in a heat-resistant structure, eg. of ferrous metal, is filled by fitting it with refractory brickwork. Instead of securing the brickwork with conventional cement, a flowable aluminous slag is produced in contact with the brickwork by exothermic reaction of a composition containing metallic aluminium and an oxidizing agent, preferably ferric oxide. The reaction, which may take place wholly or partially within the jointing space or spaces, is at such a temperature that the slag in said spaces is at least at a bond-forming temperature. Additives, eg. refractory particles, a flux, potassium nitrate or ferrous metal may be incorporated in the reaction mixture for control purposes subject to considerations described.

Abstract: Doors and other closure members for apertures of high temperature plant e.g. coke ovens, are sealed by a heat-resistant putty, conveniently a clay-based putty, applied in a tubular skin, e.g. of polyethylene. On closing the aperture the skin deforms and bursts to distribute the putty to the mating surfaces.

Abstract: It is known to fill errosion holes in ingot mould bottoms, and other holes in ferrous metal bodies, with metal produced in situ by exothermic reaction. By the present invention, the exothermic composition is used in conjunction with a particulate refractory material. The refractory is bound by a matrix of solidified slag, produced by the reaction, to form a non-metallic filling having a working surface providing a high resistance to thermal shock. A metal phase is produced by the reaction but is merely incidental.