METHOD FOR ELECTRIC-CONTACT CASE HARDENING OF PARTS Russian patent published in 2000 - IPC

FIELD: machine engineering industry branches, namely, heat treatment, possibly hardening working surfaces of parts. SUBSTANCE: method comprises steps of heating parts of ferrum-carbon alloys by passing electric current through moving contact rollers forced to worked surface and subsequent cooling of heated zone; hardening surface along stripes having width of 2-16 mm and depth of 0.2-4.2 mm and mutually spaced by intervals of 0.1-6 mm. Stripes may be intermittent and they may be arranged by staggered fashion. Relation of areas of hardened and non-hardened portions of surface consists 1: (0.3-4). EFFECT: reduced inner stresses, possibility of controlling wear resistance due to changing relation of areas of case hardened and non-hardened portions of surface. 4 cl, 3 ex