Abstract: Apparatus and method for manufacture of DR (Double Rolled) steel strip in which a continuous annealing furnace is arranged for annealing of cold-reduced steel strip passing continuously through said furnace, and a rolling mill for cold-rolling of steel strip is arranged to receive in-line the output of annealed steel strip from said furnace. The mill has at least one roll stand having a pair of work rolls of which only one is driven externally. Rolling fluid, preferably free of mineral oil, is supplied to the strip being rolled in the rolling mill, and is removed from the strip prior to entry of the strip to downstream tension-applying means.

Abstract: A ceramic burner for a hot blast stove has a central gas duct that opens into the central zone of a burner crown and side air ducts on both sides of the gas duct which also open into the central zone. To improve combustion characteristics, there is a central air duct in the gas duct opening out within it. Air is supplied to the central air duct in an upward flow which exits in two opposing directions through side openings.

Abstract: An instrument for detecting the presence of a body, comprising a detector (2) and a housing (1) in which the detector (2) is accommodated. The housing (1) is provided with at least one guide passage (6) for transmission to the detector (2) of one or more signals originating from the body. The housing (1 ) is also provided with means for supplying a gas flow (8), for example, compressed air, and a means for discharging at least a part of said flow through the guide passage (6) in such a way that, during operation at least a part of the cleaning gas leaves the housing (1) via the transmission passage (6). At the same time the invention relates to a rolling mill provided with means for determining velocities of the products to be rolled. The means for determining recording velocity comprises at least two of the instruments above and a processing unit which is linked to receive the signals from those instruments for ascertaining the velocity of a product detected by the instruments.

Abstract: In the construction of a hot blast stove, walls are made of pre-formed and baked bricks. At the joint between two walls, cast joining elements of complex shape are incorporated. The cast joining elements may be cast in situ. This avoids the need for pressing joining bricks of a variety of shapes.

Abstract: A hot-blast main for a hot-blast stove system of a blast furnace has a refractory structure comprising a plurality of courses of refractory bricks. At least a first one of the courses has at least one part thereof comprised of a plurality of expansion-joint forming bricks whose dimensions and arrangement are such that, in the cold condition of the hot blast main, there are provided radial expansion joints between the expansion-joint forming bricks and at least one adjacent part of the hot-blast main. At least some of the expansion-joint forming bricks of the first course are placed radially staggered relative to at least one adjacent such brick in each case, so that the expansion joints are provided at both the radially inner side and the radially outer side of said first course. This construction accommodates differential thermal expansions and provides good stability of the structure.

Abstract: Method for determining the image clarity of a surface of a sheet strip or similar, including projection of an image on the surface, detection of a virtual image of the image projected onto the surface and the processing of the detected virtual image into a signal which is presented as a measure for the image clarity of the surface, wherein the image reflected onto the surface is composed of a two-dimensional array of distinct light spots, whereby the processing of the detected virtual image includes the steps of (i) digitizing the detected virtual image with reference to at least one greyness discriminator value, and (ii) determining, for the greyness discriminator value, the number of distinct light spots in the digitized detected virtual image, and from steps (i) and (ii) obtaining a signal measuring image clarity of the whole area of the surface illuminated by the image projected onto the surface.

Abstract: A marking powder is disclosed for marking metallic bodies, in particular hot metallic bodies, which may be steel or other ferrous metal. Zinc is present in the marking powder in an amount 20 to 70% by weight, and it found that this results in improved legibility, which lasts for longer.The powder may be prepared by adding zinc powder to a known aluminum-based marking powder in an appropriate ratio.Coarse zinc powder was found to be better.

Abstract: The method of inhibiting the reduction of the bond strength by water of a metal-thermoplastic polymer-metal sandwich, where the thermoplastic core contains carbon to carbon double bonds, by incorporating 0.01 to 1.0% of a fatty acid component which comprises at least one fatty acid as an additive.

Abstract: In the manufacture of hot-rolled steel strip, a continuous casting machine casts a slab and a roll stand for reducing the thickness of the slab to make strip is incorporated in line with the continuous casting machine. Advantages of simplicity and rolling quality are obtained when the roll stand is a two-high roll stand having a single pair of rolls. Where there is a reheater for reheating the strip after its rolling in the two-high roll-stand, the two-high roll stand is the sole apparatus for reducing the thickness of the slab after full solidification of the slab and prior to entry of the strip into the reheater.

Abstract: A waste gas from a chemical process is treated to remove undesirable substances, especially sulphur dioxide, by contacting said waste gas with acidic solution, e.g. industrial waste solution, at pH less than 2 to effect pre-cleaning, and then contacting said waste gas with alkaline solution e.g. seawater.

Abstract: Iron foil is made by deposition of iron in an electrochemical cell having an insoluble anode from an acid electrolyte onto a moving cathode by the reaction:Fe.sup.2+ +2e.sup.- .fwdarw.Fe (foil) (I),and removing the iron foil so made from the cathode. In a regenerator iron is dissolved into the electrolyte. To avoid reduction of the foil by Fe.sup.3+ in the electrolyte, hydrogen in the form of hydrogen gas or a gas containing hydrogen is supplied to the anode, the anode being such that the anode reaction:H.sub.2 .fwdarw.2H.sup.+ +2e.sup.- (II)takes place, said reaction (II) predominating at the anode over the reaction:2Fe.sup.2+ .fwdarw.2Fe.sup.3+ +2e.sup.- (IV).The dissolution of iron in the regenerator takes place at least partly by the reaction:Fe+2H.sup.+ .fwdarw.Fe.sup.2+ +H.sub.2 (III).

Abstract: A coating thickness gauge for measuring the thickness of a coating of chromic oxideon a chromium layer on a substrate has a light source 17 for generating linearly polarized light, means 19 for splitting elliptically polarized light reflected through the chromic oxide coating into a plurality of beams 20, 21, detectors 22, 23 for intensity of each of the beams and means 24 for calculating the thickness of the coating of chromic oxide from the measured intensities. To simplify the device and the calculation, the splitting means are arranged to split the reflected elliptically polarized light into two partial beam 20, 21 polarized at a known angle relative to each other and the calculation means calculate the ellipticity from the measured intensity of the two partial beams and the thickness from the ellipticity.

Abstract: A body panel for a vehicle has a sheet and an elongate supporting structural member of uniform cross sectional shape along its length connected to the sheet for support and for mounting of the sheet to the vehicle. The structural member lies against the sheet, so as to follow the curvature of the sheet. To provide a light yet strong structure, the structural member 3 has, as seen looking at the face of the sheet at least one bend. Two or more bends are preferred. The structural member is an extruded profile, which is adhesively secured to the sheet along its whole length.

Abstract: In the manufacture of formable steel in the form of a strip with a final thickness of between 0.5 and 1.5 mm, in a number of continuous successive process stages, molten steel is continuously cast into a slab of less than 100 mm thickness and the slab is rolled into the strip. To simplify the apparatus required, and improve process control, the slab is cooled down to a rolling temperature of between 300.degree. C. and a temperature T.sub.t at which at least 75% of the material is converted into ferrite, and the rolling of the slab into strip comprises at least one reduction stage with a thickness reduction of over 30%. The rolling exit speed is less than 1000 m/min. After recrystallization, the strip is coiled.

Abstract: A channel structure, i.e. iron trough or iron runner, for flow of molten pig iron during tapping of a blast furnace, comprises a wear lining which provides the surface along which the iron flows, a permanent lining outside the wear lining and an outer lining of high thermal conductivity outside the permanent lining. The outer lining has a bottom wall and two opposed side walls thermally connected at their lower ends to the bottom wall. To improve resistance to thermal stress, outside and adjoining at least one, but not all, of the walls of the outer lining, there is at least one refractory insulating lining layer, and the other or others of the walls of the outer lining are thermally coupled to heat dissipating means.

Abstract: A gas which is intermittently and/or irregularly released e.g. carbon monoxide-containing gas from an oxygen steel converter, is collected in a gas holder and delivered from the gas holder to a user installation. To avoid wastage of gas when the average release of gas varies and to permit use of a smaller gas holder, the output rate from the gas holder is determined by deriving a modified filling level signal by filtering a filling level signal of the gas holder so as to attenuate frequencies in the filling level signal above a predetermined limit frequency by a factor of at least ten, and adjusting the rate of delivery of the gas from a gas holder in dependence on variations in said modified filling level signal, such adjustment being in the same direction (up or down) as the variation in the modified filling level signal.

Abstract: The level of the surface of a bath of molten metal beneath a fluid layer of slag in a metallurgical vessel is measured by a detector which is moved through the slag layer into the metal bath and then withdrawn. To improve accuracy and to avoid the need for a separate measurement the detector used comprises an oxygen concentration sensor which emits signals indicating the boundary between the molten metal and the slag, whereby the height of said boundary is determined.

Abstract: A shaft furnace with a steel outer shell and a refractory lining inside the shell, has a sealed tap hole structure comprising a steel sleeve fitted to the outer shell, a permanent lining inside the sleeve and a refractory sealing material within said permanent lining. To improve the gas-tightness of the tap hole structure, a metal closure plate having an opening at which the tap hole is to be formed, is located within the steel sleeve and has its periphery coupled gas-tightly to the sleeve. A metal closure sleeve is coupled gas-tightly to said closure plate around said opening thereof and extends outwardly from said closure plate. Means e.g. conductive bricks are provided for removing heat from the closure plate and the closure sleeve.

Abstract: In the manufacture of formable steel strip having a thickness between 0.5 and 1.5 mm, the following process steps are performed sequentially in a continuous process:(a) in a continuous casting machine forming liquid steel into a hot slab having a thickness of less than 100 mm,(b) hot rolling the hot slab from step (a), in the austenitic region and below 1100.degree. C., to form strip having a thickness of between 2 and 5 mm,(c) cooling the strip from step (b) to a temperature between 300.degree. C. and the temperature T.sub.t at which 75% of the steel is converted to ferrite,(d) rolling the cooled strip from step (c) at said temperature between 300.degree. C. and T.sub.t with a thickness reduction of at least 25% at a rolling speed not more than 1000 m/min.,(e) coiling the rolled strip from step (d).

Abstract: A method for bringing a plurality of steel slabs to rolling temperature uses a furnace having a controllable energy supply. To accommodate variation of slab temperature at entry, especially mixing of cold and hot slabs, at least one virtual slab corresponding to a group of the steel slabs is determined, and the energy supply is adjusted in dependence on the desired mean temperature at exit from the furnace of the virtual slab. Suitably the furnace has at least two zones each with an individually controllable energy supply, and virtual slabs are determined for the slabs in each zone. Then the energy supply in each zone is adjusted in dependence on the desired mean temperature at exit from the furnace of the virtual slab of that zone and preceding zones.