Billet Preparation Method for Railcar Hollow Axle Production

Abstract

A method is considered for preparing a hollow billet for producing a railcar hollow axle based on piercing in a two-roll screw rolling mill. A deformation regime and alignment of the screw rolling mill deformation zone are proposed in order to prepare a high quality especially thick-walled billet. Results are given for prior study of especially thick-walled pipe preparation for railcar hollow axles in the VMZ 70-270 pipe rolling unit.One of the main areas for developing the infrastructure in Russia is railway transport improvement, providing needs of the modern economy. More than 80% of freight movement of all forms and above 40% of long distance and suburban passenger transport fall within railway transport [1].A reduction in wagon weight is particularly important in view of an increase in movement rate, and also load capacity of the mobile component. One way of resolving this problem is a reduction in the weight of unsprung parts [2], and lightening of wheel pairs due to use of hollow instead of solid wagon axles. As is well known, during transfer of torsional moment internal stresses arise in a shaft cross section. During twisting, stresses in an axial shaft equal zero, and at points close to the axis they are very small and increase as distance increases from the axis, reaching a maximum value at an outer surface [3]. Thus, the material of the central part of a shaft during transfer of a torsional moment is almost unloaded and unused, and serves as ballast. Therefore, a wagon axle should desirably be manufactured as a hollow body without detriment for strength, and with a marked weight reduction (Fig. 1).Solid wagon axles are used in moving parts operating within the territory of Russia. In spite of the high efficiency of wagon hollow axles (saving metal, reduction in unsprung weight, reduction in stress level due to dynamic loads, etc.) currently no reliable and effective industrial technology has been developed that would meet all of the required specifications for manufacture of these axles. Wagon hollow axles are mainly used abroad in rapid high-speed trains.Manufacturing technology for a wagon hollow axle includes preparation of a billet with an axial hole from which the required profile is obtained. Shaping a billet is possible by different methods: in periodic rolling mills, machining, forging, stamping, etc. Currently both solid and hollow wagon axles of wheel pairs should desirably be manufactured by forging

Effect of process parameters on forming quality of hollow axle blank with rotary piercing

“…Therefore, in the field of inner hole forming, some scholars began to focus on piercing technology. V.P.Romanenko tried to form hollow axles by first rolling and then forging, that is, the inner hole was formed by two-roll piercing, and then the tube blank was forged on a fast forging machine, and a number of 1:1 hollow axles [11][12] were successfully trial-produced, but the shape of the capillary after the piercing stage was not analyzed. In this paper, a three-dimensional rigid-plastic finite element model of cross-rolled piercing high-speed railway hollow axle billet is established based on SimufactForming finite element software.…”