METHOD OF HARDENING THE SURFACE OF IRON OR STEEL WORKPIECES BY DIFFUSION IN A GLOW DISCHARGE

摘要

1349290 Hardening ferrous surfaces ELEKTROPHYSIKALISCHE ANSTALT BERNHARD BERGHAUS 16 Sept 1971 [21 Sept 1970] 43315/71 Heading C7U [Also in Division H1] A work-piece is treated by a glow discharge process in which the intensity is at least temporarily varied over one part of the surface relatively to another, so that a hardening agent from the treatment gas is diffused to different depths. As particularly applied to the worm 8 of an extruder for plastic reinforced with mineral powder or glass fibre, where it is desired to have a hard wear resistant nose and a more ductile drive section at the rear end, the latter region is surrounded by an annular electrode 10 which is connected by insulated connector 17 and potentiometer 22 to power source 22. The work-piece surface may be hardened by diffusion of hydrogen, carbon boron, oxygen or nitrogen.