Abstract: Metallic sheets, wires, bars or other products are descaled by sweeping their surfaces with one or more laser beams to detach an adhering oxide film along lines traced by the beam sweep. The film fragments, still loosely adhering at locations between the sweep lines, are then removed mechanically, chemically or electrolytically.

Abstract: A method of removing surface defects from the surface of a steel product, such as a slab designed for rolling, wherein the defects are melted by an arc generated by an arc welding apparatus having a non-consumable electrode, a guide nozzle about the electrode to maintain an inert gas atmosphere immediately thereabout, and a shield nozzle about the guide nozzle to inject a mainly carbon dioxide gas therefrom, and a deoxidizer is applied to the molten pool formed in the welding operation so as to cover the surface thereof with a slag formed by the deoxidizer which is oxidized.

Abstract: A method for producing an individual, fin-free, spot scarfing cut on the surface of a workpiece characterized by directing at the spot to be scarfed, which has first been brought to a molten state, an oxygen stream at an inclined angle to the work surface, the intensity of said oxygen stream being gradually diminished toward its lateral edges so that the flow of oxygen at the edges of said stream is insufficient to scarf the workpiece, but sufficient to oxidize molten metal at the edges of the scarfing reaction zone, thereby preventing molten metal from solidifying on the work surface along the edges of the scarfing cut in an unoxidized state.

Abstract: A method and apparatus for making an instantaneous thermochemical start on the surface of a metal workpiece.The method resides in the use of laser beam focused to a small spot to bring the ferrous workpiece to ignition temperature in combination with a high intensity oxygen jet to cause the initiation of the thermochemical reaction. The laser beam may impinge the workpiece at a point about 1 cm behind the spot where the oxygen impinges the workpiece surface to a point about 10 cm ahead of such spot. Accordingly, the laser beam may penetrate the high intensity oxygen jet and still cause the thermochemical reaction to start instantaneously.The apparatus resides in a scarfing machine having a scarfing nozzle, an oxygen spreader nozzle and a laser assembly associated therewith. The oxygen spreader nozzle is mounted so as to provide high intensity oxygen jet on the surface of the workpiece ahead of the scarfing oxygen effluent from the scarfing nozzle.

Abstract: A scarfing nozzle for producing a fin-free scarfing cut at least as wide as the width of the nozzle. The nozzle comprises an oxygen gas passage terminating in a nozzle discharge orifice characterized by having a central section and at least one end section. The central section is defined by parallel upper and lower edges and is adapted to discharge a sheet-like stream of cutting oxygen of uniform intensity across the metal body to be scarfed. The end section is defined by having at least one of its edges inclined such that the height of the end section is gradually reduced to a lesser value towards the side edge of the orifice but remaining greater than zero at the edge so as to diminish the intensity of the oxygen stream towards the edge of the orifice to the point where the flow of oxygen discharged at the edge is insufficient to scarf the workpiece but sufficient to produce a fin-free scarfing cut at least as wide as the width of said nozzle.

Abstract: A method for making an instantaneous thermochemical start on the surface of a ferrous metal workpiece, comprising the steps of: (a) contacting a preselected spot on said surface where the reaction is to begin, with the end of a ferrous metal wire which has been heated to its ignition temperature in an oxygen atmosphere, (b) impinging a high intensity jet of oxygen gas on said surface at a point 1 to 15 cm. behind said spot, thereby causing an immediate scarfing reaction to begin and a molten puddle to form at said spot, and (c) continuing the impingement of a high intensity jet of oxygen on said puddle until the puddle has spread to a preselected width. Thereafter, the spreading oxygen stream may be left on and used to carry out the scarfing reaction, or it may be turned off and another oxygen stream may be impinged on the spread puddle at an acute angle to the work surface in order to "take over" and carry out the scarfing reaction.

Abstract: The present invention relates to a method and an apparatus for initiating and maintaining a thermochemical process of scarfing the surface of a workpiece to remove surface defects like, e.g., cracks, in which there is used a unit of torches, continuously moving in relation to the workpiece, in which a spot or zone in the surface is burnt in oxygen or in other reacting medium.

Abstract: A method and apparatus for flame-cutting cracked corner portions from continuously cast metal workpiece. The cutting torches are positioned adjacent the corners of the workpiece and are aimed downwardly at angles of about 35.degree. to 55.degree. with respect to the vertical and at angles of about 80.degree. to 100.degree. with respect to planes which bisect the corner angles of the workpiece. Preferably the torches are aimed downwardly at angles of about 45.degree. and approximately perpendicular to the bisecting planes. In this manner the depth of segment cut from the workpiece is closely controlled and the material removed from the workpiece is directed away from the surfaces thereof.

Abstract: In the method of scarfing surface defects of to-be-scarfed metal material as said material is moving relative to the scarfing machine with scarfing nozzle, the improvement, which comprises a step of supplying oxygen into the consumable electrode pipe so provided as to be directed to a scarfing point on the surface of said to-be-scarfed metal material, for jetting the oxygen from the tip of said electrode pipe, a step of feeding said electrode pipe until its tip contacts said metal material, a step of heating rapidly the contacting portion respectively of said electrode pipe and of said metal material with electrical energy and heat of oxidation so that the temperature of such portion may rise to scarfing start temperature, and a step of initiating the scarfing process instantaneously from such temperature rising portion with the oxygen jetted to said scarfing nozzle.

Abstract: A process for flame scarfing places of errors or surface defects on a work piece such as ingots, slabs or the like, by means of at least one flame-scarfing torch is characterized by raising and/or accelerating the flame-scarfing torch from its flame-scarfing position prior to the end of the place of error without changing the other flame scarfing parameters.