文档介绍：外文原文:
Casting and its processes
Introduction
Manufacturing process can be classified into two general groups known as primary and secondary processes. The primary processes, namely, casting, forging, cold heading, cold extruding, brake forming, and so on, are those that convert raw material into shapes. These forming methods include both hot and cold working processes and, in general, will still require further finishing operations in order to obtain an end product.
The secondary processes are those that bring the part to the dimensions and surface finish specified. One may also include in the secondary processes such operations as heat treating and surface treatments for corrosion resistance, hardness, and appearance. Secondary processes are planning , turning ,milling, drilling , boring , reaming , broaching , grinding , honing ,lapping , polishing , and special methods of metal removal such as electrochemical machining. Operations like screw cutting, tapping, thread milling, gear cutting, and so on ,are secondary processes that are merely adaptations of one of the aforementioned processes that are merely adaption of one of the aforementioned processes.
plete discussion of these procedures is beyond the scope of this text. Therefore, we will confine ourselves to inct descriptions of the most prominent techniques.
Castings
Castings are identified by the type of m