Verfahren und Vorrichtung zum Plasmalichtbogenumschmelzen der Oberfl{chenschicht eines flachen Metallwerkst}cks

The method provides for placing a plane workpiece (1) in its initial position horizontally between cooled beams (2 and 3) of a crystallizer. Plasma-arc burners (6) are placed in a row above the workpiece (1) and across its parallel edges (1a and 1b) so that the anode spots of the extreme burners (6a and 6b) are limited by the edges of the workpiece (1). A plasma-arc generating gas and electric current are fed to the plasma-arc burners (6), the workpiece thus being heated and a bath (8) of molten metal being produced on it, its length being equal to the distance between the edges (1a and 1b) of the workpiece (1). The workpiece (1) and the plasma-arc burners (6) being moved in relation to each other in a horizontal plane and along the edges (1a and 1b) of the workpiece (1), the displacement of the bath (8) of the molten metal is thus ensured along the surface of the workpiece (1). As a result a remelted surface layer is obtained on the workpiece its thickness being equal to the depth of the bath (8). A device implementing this method comprises a pressurized chamber (11) and a crystallizer mounted therein and including two beams (2 and 3) which are oriented in a horizontal plane and are parallel to each other. Plasma-arc burners (6) connected through supply lines (12, 13, 14) to sources of a plasma-arc generating gas, of electric current and cooling water are mounted inside the chamber (11) on shafts (17). Each of the shafts (17) is mounted by means of a seal bushing (18) in the wall of the chamber (11) so that its axis is parallel to the beams (2, 3) and is provided with a drive (24) for its own axial rotation. The device is further provided with a drive for reciprocal displacement of the workpiece (1) and the shafts (17) in a plane parallel to the beams (2, 3), that drive being connected with at least one of the elements participating in the said displacement.