Cast steel railway wheel

#The subject matter herein relates generally to casting objects using a casting operation.

#The steel railway wheels are manufactured during a casting operation wherein molten steel is poured into a machined graphite mold. The mold typically includes a top half or cope that is usually a graphite block and a bottom half or drag that is also usually a graphite block. The top portion or front face of the object being cast is machined in the cope and the bottom portion or rear face of the object being cast is machined in the drag. The mold includes sections that form a hub, plate and rim of the railway wheel. When the cope section and drag section are combined to form a complete mold, such complete mold is positioned at a pouring station wherein molten steel is poured into the cavity in the mold to form the hub, plate and rim of the railway wheel.

#In some known assemblies, a central riser is provided in the cope section of the mold such that additional molten metal can be held as necessary to downwardly fill into the mold during cooling and solidification of the railway wheel just after pouring. There are accepted standards for porosity of steel railway wheels that must be met by designing the central riser to hold an adequate volume of metal to fill downwardly into the molds during cooling and solidification of the wheel. Upon filling of the mold cavity and central riser, the metal pouring is stopped and the graphite mold is then moved from the pouring station allowing sufficient time for the steel to solidify before the cope and drag sections are separated.

#FIG. 1 illustrates a railway wheel formed in accordance with an exemplary embodiment.

#FIG. 2 is a top view of the wheel shown in FIG. 1.

#FIG. 3 is a rear view of the wheel shown in FIG. 1.

#FIG. 1 illustrates a railway wheel 100 formed in accordance with an exemplary embodiment. The wheel 100 includes a hub 102 having an axial bore 104 arranged to receive, in a conventional manner, one end of an axial (not shown). Formed integrally with the hub 102 and extending radially thereof is a plate 106. A rim 108 is peripherally formed at the radially outer edge of the plate 106. The rim 108 has a tread surface 110 and flange 112 extending radially outward of the tread surface 110 on the inboard side of the wheel 100. In an exemplary embodiment, the rim 108 is axially offset from the hub 102 toward the outboard side of the wheel 100 in a conventional manner.

#In an exemplary embodiment, the wheel 100 is formed using a casting process where molten metal, such as molten steel, is poured into a mold cavity to form the wheel 100. In an exemplary embodiment, the molten steel is top poured into the mold cavity to fill the mold cavity. Alternatively, the molten steel may be bottom pressure poured into the mold cavity. A central hub riser is used to store excess molten metal for a period of time during the casting process to be able to supply the molten metal downwardly into the cavity to assure complete filling of the mold cavity and proper porosity of the metal in the wheel 100 after solidification. The molten metal remains liquid for a long enough period of time to supply the mold cavity with molten metal during cooling and solidification of the wheel 100. The molten metal flows from the hub riser through the plate 106 into the rim 108 as the wheel 100 cools and solidifies. The solidification generally takes place from the outside of the wheel 100 to the inside of the wheel 100.

#In an exemplary embodiment, the wheel 100, particularly at the plate 106, has areas of different thicknesses, for example some thick areas and some thin areas, to balance adequate molten flow of the metal during solidification through the thicker areas with the competing advantage of reducing the overall weight of the wheel 100. The thin areas of the plate 106 reduce the overall weight of the wheel 100 as less metal material is provided in such areas. The thick areas of the plate 106 act as gutters or pipes to feed the rim 108, thus creating molten tubes for the molten metal to flow during cooling and solidification of the wheel 100. As the wheel 100 cools from the outside in, the wheel 100 in the thicker area remains molten (non-solidified) for a longer period of time, allowing the molten metal to flow from the hub 102 to the rim 108 for a longer period of time.