Numerical Analysis of the Skew Rolling Process for Rail Axles

Abstract

The paper describes a new method for producing stepped rail axles. The method is based on the skew rolling process. With this method, the product is formed by three tapered rolls located every 120• on the perimeter of the billet. Positioned askew to the centerline of the billet, the rolls rotate in the same direction and with the same velocity. At the same time, they get closer together or go apart depending on the desired cross sectional reduction of an axle step. In addition, the workpiece is shifted lengthwise relative to the rolls by the translational motion of the workpiece-holding chuck. In order to verify the designed method for producing rail axles, a series of numerical simulations were performed using the Simufact.Forming v.12 simulation software. The numerical modeling enabled the determination of maps of the effective strain and temperature in the finished product as well as variations in the loads and torques during rolling. The numerical results unambiguously confirm that the skew rolling method can be applied to form parts of considerable dimensions (the modeled axles had a length of 2146 mm and their maximum diameter was 202 mm).Keywords: Skew rolling, rail axle, FEM W artykule opisano metodę wytwarzania stopniowanej osi wagonowej bazującą na procesie walcowania skośnego. W metodzie tej wyrób kształtowany jest za pomocą trzech rolek stożkowych, rozmieszczonych na obwodzie wsadu co 120• . Rolki te ustawione są skośnie względem osi wsadu, a w trakcie kształtowania obracają się z jednakową prędkością w tę sa-mą stronę oraz jednocześnie zsuwają lub rozsuwają się -w zależności od redukcji przekroju poprzecznego kształtowanego stopnia osi. Dodatkowo, wyrób kształtowany przesuwany jest wzdłużnie względem rolek, w wyniku ruchu postępowego uchwytu utwierdzającego jeden z jego końców. Sprawdzenia poprawności założonej koncepcji kształtowania osi wagonowej dokonano w drodze symulacji numerycznej wykonanej w programie Simufact.Forming v.12. W efekcie wykonanych obliczeń uzyskano mapy intensywności odkształcenia i temperatury w ukształtowanym wyrobie oraz wyznaczono przebiegi sił i momentów w trakcie walcowania. Jednoznacznie potwierdzono możliwość kształtowania wyrobów o dużych gabarytach (długość osi wynosi 2146 mm, a jej średnica maksymalna 202 mm) metodą walcowania skośnego.

An Innovative Method for Forming Balls From Scrap Rail Heads

“…The simulation involved the modeling of a process for forming 80 mm diameter balls from a rail head described by a length of 92.5 mm. The authors of this paper have considerable experience in performing numerical modeling of different metal forming processes, and the applied simulation software, Simufact.Forming, enables obtaining results which show a good agreement with experimental findings [10][11][12][13][14][15].…”

FEM Analysis of Loads and Torque in a Skew Rolling Process for Producing Axisymmetric Parts

“…Forming v. 12. This software has been used by the author and the others researchers to investigate skew, cross and ring rolling processes [8][9][10][11][12][13][14], and the numerical results showed good agreement with experimental results. The results will be used when designing a laboratory stand for skew rolling which will be constructed at the Lublin University of Technology in the near future.…”

“…Instead, the workpiece is fastened in fixed plane, while the axial motion of the chuck is replaced with axial feed of the rolls, which does not affect the kinematics of this process and facilitates the numerical simulation (axial load on the chuck is defined by a sum of axial loads acting on the rolls). This model of skew rolling was previously used by the author to investigate the skew rolling process for a axle [6] and a stepped shaft used in light trucks [8]. The skew rolling process is defined by the following variables ( Fig.…”

Analysis of Helical Rolling Process of Balls Formed From a Head of a Scrapped Rail

“…Forming software. This software was fre-quently used by the author and other researchers for the analysis of cross and helical rolling pro-cesses [12][13][14][15][16][17] and the results from calculations were in good compatibility with the results of experimental research. It was assumed in calculations that the behavior of the formed material (steel of R200 type), in hot metal forming conditions, is described by the following equation: (1) where: σ p -yield stress, MPa; φ -effective strain; φ̇ -strain rate, s…”