METHOD FOR MAKING CHROME-PLATED PISTON RINGS Russian patent published in 2002 - IPC

FIELD: plastic metal working in combination with heat treatment and strengthening of rubbing surfaces, for example by chrome plating. SUBSTANCE: method comprises steps of twisting helix of steel strip, basing helix onto mandrel with predetermined diameter, fixing ends of helix and working it, particularly by thermal stabilization and polishing; removing helix from mandrel and preparing its surface for chrome plating; before chrome-plating basing helix onto mandrel with predetermined diameter and after chrome-plating removing helix from mandrel and realizing dehydrogenation in furnace at temperature up to 250 C; then basing helix onto mandrel or in sleeve with predetermined diameter and cutting it by separate rings; at process of preparing helix surface for chrome-plating performing its trimming, etching and degreasing. It provides uniform-thickness chrome-plated coating without shearing, exfoliation and dendrites. EFFECT: enhanced quality of chrome-plated piston rings. 2 cl, 2 dwg