FORFARANDE FOR FORMNING AV EN ENDVEGG MED ETT KONCENTRISKT URTAG I ETT RORFORMIGT ARBETSSTYCKE

Concentric recessing a tube endwall in integrated conveyor idler manufacture inverts the end produced by doming the edges together and is carried out on a blank rotating at forging temperature. To expand the range of suitable blanks and the dimensioning of the end product, forming is in two stages. In the first the domed end (2) of the blank (1) is formed to produce a flat surface (5) larger in diameter (D) than the eventual recess base by amounts between 2R and 3R where R is the free bend radius of the blank wall. In the second stage, final forming is conjoined with inversion by a press tool (6) of the same shape and size as the eventual recess which is forced into the flat area (5). A friction reducing roller etc (7) works at a tangent to the blank to complete the endwall forming process. Press tool and roller speed ratio should be 0.40 to 0.75. In the pre-forming operation the endwall should be truncatedly coned with the generatrix at 30 - 40 deg. PHI to the main axis. This ensures optimum metal flow and distribution in the final product.