GAS CUTTING METHOD OF STEEL MATERIAL

摘要

PURPOSE:To remove thoroughly cutting slag without deep gouging by ejecting gas consisting essentially of oxygen from a nozzle on a rear side in an upward direction onto the line intersecting with a cutting groove and specifying the ejecting pressure and pressure distribution of said gas. CONSTITUTION:A slit nozzle having a blind part at the center and having finely divided right and left slit holes 11 is used as a nozzle 9 on a rear side which advances simultaneously with a cutting torch 2, and gas is ejected through said nozzle in the direction at a right angle to a cutting groove 4 from behind the progressing direction of the groove 4. Gas contg. >=50% oxygen is ejected in this state at an upward angle alpha ranging 10-25 deg. onto the line M intersecting with the groove 4 passing the position spaced at 10-80mm. (L) backward from the position O at the cutting tip. The pressure of the gas to be ejected is distributed into a saddle shape having two peaks on the right and left of the groove 4 and the gaseous pressure is so set as to satisfy the equations I , II, III (H1; the max. pressure in the slag sticking range on one side of the groove 4, H2; the same pressure on the other side of the groove 4, H3; the pressure at the cutting edge on one side of the groove 4 and H4; the same pressure on the other side of the groove).