| 摘要 |
PURPOSE:To prevent the delay in a drag line and to improve the efficiency and yield of cutting, by tilting a nozzle at a prescribed angle gradually from a perpendicular state in the stage of cutting in and ending in gas cutting. CONSTITUTION:A cutting nozzle is tilted at >=20 deg.theta1 delay angle with respect to the cutting direction to preheat the material and the nozzle is gradually returned to a perpendicular position upon starting of cutting. The reason for limiting the angle theta1 for cutting in of the nozzle lies in that if the angle exceeds 20 deg. the stripping and removal of the molten slag produced in the cut groove are difficult and that a defect and the like on the cut face arise. The reason for returning gradually the nozzle to the perpendicular position lies in that the actual cut thickness otherwise increases and that the drag is increasingly delayed. If the material is cut by inclining the nozzle at >=20theta2 angle to the cut groove side prior to ending of the cutting, the cutting is effected in the same way as in cutting the material thinner than the actual thickness as in the stage of cutting in, whereby the delay in a drag line 3 is eliminated. The material is thus cut without having any uncut part on the bottom end in the terminal part of the cut face. |
