GB1489812A - Method of making finished steel castings - Google Patents

Abstract

1489812 Finishing steel castings EVANS PRODUCTS CO 6 Jan 1975 [7 Jan 1974] 488/75 Headings B3F B3W B3A and B3V A method of making finished steel castings of high accuracy of shape and dimension without excessive cold finishing involving grinding, straightening or machining off of gates, rivers, flash, &c., is by casting the objects in moulds where the gates are in the region of the parting line on the lateral surfaces of the casting. After cooling the casting to a non-homogeneous ascast grain structure, the casting is reheated and homogenized at a temperature above the upper critical temperature until the structure is uniformly austenitic, and while the casting is at (or near) that temperature, i.e. in a plastic state, placing it in a set of co-operating dies which shear off the gates, rivers and parting line flash. The dies may be of such a type that, simultaneously with the shearing of the gates &c., the castings may be dimensionally altered by pressing or alternatively the castings may be coined or pierced. While the pressing, coining or piercing operation may be carried out in the same set of dies as the shearing, multiple sets of dies may be used in rapid succession, so that reheating to above the upper critical temperature is not necessary. In a modification, the shearing/working dies may be of such a design as to alter the shape of the casting to provide a partially enclosed cavity in the final casting without the necessity of using a core in the original casting. The final step in the process is the removal of the sheared, coined, pressed, pierced or formed casting from the die followed by cooling, which may be controlled.