METHOD FOR MAKING AND EXPLOITING DRIFTS OF PILGER MILLS FOR PRODUCING HOT ROLLED TUBES OF LARGE AND MEAN DIAMETERS Russian patent published in 2008 - IPC B21B25/00 B23P6/00 

FIELD: production of rolled tubes, possibly manufacture and operation of drifts of pilger mills.

SUBSTANCE: method comprises steps of casting ingots of carbon steels; applying onto ingot surface by surfacing heat- and wear- resistant layer; making from ingots drift blanks by pilger rolling; performing heat treatment of drift blanks; then performing mechanical working of blank to final size for further strengthening of it due to rolling around by means of roller. During operation of drifts after occurring of net of burnout cracking drifts are subjected to multiple returning till removing heat- and wear-resistant layer. Then new heat and wear resistant layer is applied by surfacing, heat treatment and mechanical working till final size are realized for further strengthening of blank due to rolling around by roller. Heat and wear resistant layer is applied beginning from bottom end of ingot along 2/3 of its height. After returning of drifts heat and wear resistant layer is applied along 2/3 of their length beginning from drift head with further smooth transition along length 100 - 150 mm. Thickness values of heat and wear resistant layer on ingots and on drift blanks are determined according to given expressions.

EFFECT: improved strength of drifts, rational metal consumption.

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