INFLUENCE OF WHEEL BILLET STAMPING SCHEMES ON POWER MODES OF FORMING PRESS OPERATION AND ON WEAR OF THE DEFORMATION TOOL

Abstract

Ensuring the stability of the dimensions of the stamped-rolled railway wheels, the rational power modes of the press operation and durability of the metal deformation tool parts, as well as reduction of the initial billets mass, are actual scientific and technical tasks. This durability largely determines the costs associated with the choice of steel grade for dies, technology of their manufacture and process lubrication. In the present work, based on the results of finite element modeling, the analysis of the influence of stamping schemes of wheel billets on the power modes of operation of a forming press and on wear of the deformation tool was made in relation to modern press rolling lines. It is shown that the stamping schemes, which provide for the regulated distribution of metal between the central and peripheral parts of the billet delivered to the stamps, are characterized by a  rational power mode of the forming press. The average force in this case is 63  –  70  % of the average force when stamping out of the billets, sagged by smooth slabs. Elimination of premature filling of the hub contributes to a decrease in the average (by the upper and lower stamps) of the wear of molding dies by 20  –  24  %. It was established that in the process of metal reduction in the disk zone, as the earlier formation of the resistance to flow of metal from the side of the molding ring is formed, the smaller slip of the deformable metal relative to the surface of the molding dies is in the zones of their most intense wear (the transition from the disk to the rim) and, as a consequence, less wear amount appears. It has also been found that the metal deformation scheme in molding dies ensuring filling of the flange during axial metal reduction in the rim zone, decrease the metal slippage relatively to the surface of the molding dies at the zones of transition from the disc to the rim. The additional decrease of wear in this case is 27  –  33  %. Ensuring the dimensions stability of the stamped-rolled railway wheels is possible on the basis of stamping schemes, providing a regulated distribution of metal between the central and peripheral parts of the billet and its self-centering in molding dies. This will reduce the weight of the initial billet by 7  –  10  kg.