Abstract: The present invention relates to a high pressure, rapid cutting tip nozzle which provides a cutting oxygen jet hole 2b in the front end surface, and provides concentrically from the inside, with this cutting oxygen jet hole 2b as the center, a first oxygen jet hole group 7a, a first fuel gas jet hole group 8c, a second fuel gas jet hole group 8a, and an oxygen jet opening 9a, and wherein steel is cut by the high pressure gas flow jetting from the cutting oxygen jet hole 2b, and in particular is characterized in the front end of flow paths 9b and 9c, which branch from the flow path 9 leading to the oxygen jet opening 9a, opening on the side surface of flow paths 8 and 8b, which lead to the first and second fuel gas jet hole group 8c and 8a, at a point within 10 mm from said front end surface. According to the present invention, gas cutting of steel can be carried out with high efficiency and safely.

Abstract: A method for removing burrs in a continuous rolling process including the steps of joining the rear end of a preceding billet with the front end of a succeeding billet using a flash butt welding method while both billets are moving, and grinding a burr on the welded part of the joined portion using a plurality of grinders while the billets are moving and while rotating the grinders and moving the grinders synchronously with the travelling speed of the billets. A grinding machine for continuously rolling a round billet includes a travelling body shuttling along the direction of movement of the round billet, a turret ring rotatably supported by the travelling body, and a plurality of grinding devices arranged in a movable manner within a radius of the turret ring, wherein the grinding devices include grinders which are set at a tilted angle relative to the center axis of the rotatable turret ring.

Abstract: A trimming apparatus comprises a trimming mechanism including a carriage movable along the path of travel of a sheet segment which has been cut from a continuous metal sheet by melting a localized area thereof, a slag being formed on an end of the sheet segment. An engaging member is mounted on the carriage and engageable with the sheet segment. A burner is mounted on the carriage and movable along the end of the sheet segment to remove the slag therefrom. There is also disclosed a method of cutting a continuous metal sheet by melting a localized area thereof, and trimming the end of the cut sheet.