METHOD FOR MAKING CORRUGATED TUBES Russian patent published in 2004 - IPC

FIELD: plastic working of metals, namely manufacture of single-corrugation bellows with cylindrical shells.

SUBSTANCE: method comprises steps of preliminary radial forming of corrugations and axially upsetting of blank in die while applying inner pressure; one or more calibration stages. At least one calibration operation is realized at placing preliminarily shaped bellows onto cylindrical mandrel and rolling around outer surface of bellows at rotation of mandrel due to radial feed of profiled roller to mandrel axis. Gap value between calibrating surfaces of mandrel and roller is no less than thickness value of bellows. It is possible to use mandrel with radial annular groove and cylindrical roller with radial annular protrusion.

EFFECT: enhanced quality of single-corrugation bellows due to lowered thickness difference of cylindrical shells and recess of corrugation.

4 cl, 2 dwg, 1 ex