8/7/2023 0 Comments Crossover symmetry iron scrap![]() ![]() Nevertheless, it can also be conducted under warm-working conditions. conducted numerical and experimental studies to determine parameters of a cross-wedge rolling process allowing for hot forming of shafts made of Nimonic ® 80A and Nimonic ® 115 superalloys.Ĭross-wedge rolling is usually performed as a hot-working process. ![]() found that the CWR technique can be used for producing toothed shafts made of aluminium alloy 2618. proposed a solution for producing preforms made of magnesium alloy AZ31, while Pater et al. studied the use of CWR in the production of shafts made of titanium alloy Ti6Al4V. Nonetheless, this technique has been employed to form parts made of nonferrous metal alloys in recent years. The CWR technique is primarily used for forming steel parts. were able to design an innovative method for manufacturing hollow valves via cross-wedge rolling and die forging. By eliminating the failure modes characteristic of CWR processes for hollow parts, Ji et al. found that the use of an internal mandrel prevents axial metal flow, and, as a result, they were able to produce parts with the intended side wall thickness. This failure mode can be prevented easily by the application of small spreading angles or three rolls in the rolling process. The primary failure mode in the rolling of such parts is excessive cross-sectional ovalization. There have been numerous studies on the application of the CWR method for manufacturing hollow parts. After that, the cylindrical billet is formed into balls with a diameter bigger than that of the billet. First, heads of scrap railway rails are formed into a cylindrical billet. designed a cross-wedge rolling technique for producing balls wherein balls are formed in two stages. The results of a numerical analysis of cross-wedge rolling for billets with a square cross section were reported by Ma et al. Products without axial symmetry can also be formed by cross-wedge rolling from billets with non-circular cross sections. Pater devised a cross-wedge rolling process for shafts with eccentric steps, consisting in the use of special guides that act on the billet and change its position while the tool cuts into the material. , who designed rollers with special profile surface for cam forming. An interesting solution was proposed by Zheng et al. To explore new applications for the CWR technique, researchers have turned their attention to parts that do not have axial symmetry, for example, the application of the CWR technique for manufacturing screw spikes and threaded shafts. A multi-wedge rolling method has been proposed for manufacturing balls for ball mills, which makes it possible to manufacture dozens of balls simultaneously. The solution is recommended for the production of considerably long parts such as axle shafts for cars and railway axles. To shorten the tool length and increase efficiency of the process, multi-wedge tools are used, as this design solution enables the forming of a workpiece by several pairs of tools at the same time. Given these advantages, a growing interest can be observed in the use of this metal forming technique in recent years, which is reflected in numerous research works focused on developing the technological potential of CWR and eliminating its shortcomings.Īs far as new trends in the use of CWR are concerned, following tendencies can be seen. It has numerous advantages including high efficiency, low material consumption, high-strength properties and eco-friendliness. The experimental results demonstrate that the proposed solution is a viable method for end-face cavity removal.Ĭross-wedge rolling (CWR) is an advanced method for producing axisymmetric products such as stepped axles and shafts. Rolling tests were performed using a billet with its length selected in compliance with the established dependencies. The equations for calculating the concavity allowance were verified in an experimental process for manufacturing ball pins with the use of flat tools. ![]() Relationships between these parameters are examined in order to establish dependencies enabling quick and simple selection of a concavity allowance in order to remove the cavities. Twenty-one different cases of rolling were analysed by finite element method to determine the effects of process parameters such as the wedge tool angle, the temperature of material, the tool velocity and the reduction ratio on the depth of end-face cavities. The cavity depth was measured by the displacement method. The problem of end-face cavity formation in parts produced by cross-wedge rolling was studied in order to reduce material consumption. ![]()
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