METHOD FOR MANUFACTURING OF MANDREL FOR PIPE WINDING WITH AT LEAST ONE HELICAL RECTANGULAR SLOT, MANDREL FOR WINDING OF PIPE AND PIPE OF FLAKY COMPOSITE MATERIAL Russian patent published in 2009 - IPC B29C53/82 B29C53/56 

FIELD: technological processes.

SUBSTANCE: group of inventions is related to method for manufacturing of mandrel for winding of pipe with at least one helical rectangular slot, mandrel manufactured according to this method and pipe of flaky composite material, which is manufactured with application of this mandrel. Method consists in the fact that helical plate is installed and fixed onto cylindrical body. Plate is made of flat strips with fixed length, which are arranged in a butt joint, providing for a specified angle of helical line lift by clamps or template with sweep slot, or by plate edging into previously arranged helical slot. Then location holes are made together in plate and body, besides holes arranged in body are threaded. At least two screws are screwed into holes per each strip, clamps or template are removed, and plate is finally pressed, while deforming it to a helical shape. Ledges produced due to mismatch of strip ends are cleaned out, for instance by means of scraping, with gradual reduction of thickness and width of removed layer at the length that does not exceed half of strip length, providing for gradual reduction of strip side surfaces curvature to its middle and constant curvature of its upper surface. Mandrel comprises cylindrical body and helical plate. Helical plate is arranged as discrete. Side surfaces of plate are arranged with alternate curvature, at the same time middle of discrecity section is arranged with curvature less than averaged curvature for the whole plate, and zone of sections joint - with higher curvature. At the same time each section of plate is fixed with the help of at least two mount screws. Pipe comprises multi-layer power shell and internal bearing layer with rectangular corrugation, with rectangular slot arranged in it, with the possibility of corrugation deformation in circumferential direction relative to power shell by value of error of plate installation onto mandrel, in process of pipe removal from mandrel after its final thermal treatment. Slot is arranged as discrete, side surfaces of which are arranged with alternate curvature, at the same time middle of discrecity section is arranged with curvature that is less than averaged curvature for the whole slot, and zone of sections joint - with higher curvature.

EFFECT: improved manufacturability of making and quality of mandrel, simplified monitoring of parametres in helical plate installed onto mandrel body, and also increased reliability of produced pipe operation due to exclusion of pipe damages in zone of slot as it is dismantled from mandrel of higher quality.

4 cl, 13 dwg