1.2Ferrous Metals and Alloys
By virtue of their wide range of mechanical, physical, and chemical properties, ferrous metals and alloys are among the most useful of all metals. Ferrous metals and alloys contain iron as their base metal: the general categories are cast irons, carbon and alloy steels, stainless steels, tool and die steels.
The term cast iron refers to a family of ferrous alloys composed of iron, carbon(ranging from
2.11% to about 4.5%),and silicon(up to about 3.5%).Cast irons are usually classified as follows:
1.Gray cast iron,or gray iron;
2.Ductile cast iron, nodular cast iron, or spherical graphite cast iron;
3.White cast iron;
http://doc.guandang.netpacted graphite iron。
（ ），它包含铁碳（2.5%—4.5%）和硅（ 3.5%）铸铁的分类如下1.灰铸铁2.球墨铸铁3.白口铸铁4.可锻铸铁5.如墨铸铁
The equilibrium phase diagram relevant to cast irons is shown in Fig.1.1,in which the right boundary is 100% carbon,that is pure graphite.The eutectic temperature is 1154hC (2109hF), and so cast irons are completely liquid at temperatures lower than those required for liquid steels. Consequently, iron with high carbon content can be cast at lower temperatures than can steels. 有关铸铁的平衡相图如图1.1所示 其右边界是100%的碳 那是纯石墨，其共晶温度是1154℃因此铸铁可以在比那些熔化钢更低的温度下完全液化所以含碳量较高的铸铁的浇注温度比钢低。
Carbon steels are generally classified by their proportion(by weight) of carbon content.
1.Low-carbon steel, also called mild steel, has less than 1.30% carbon. It is generally used for common industrial products, such as bolts,nuts, sheet, plate, and tubes, and for machine components that do not require high strength.
Conventional machining is the group of machining operations that use single- or multi-point tools to remove material in the form of chips.Metal cutting involves removing metal through machining operations.Machining traditionally takes place on lathes, drill presses, and milling machines with the use of various cutting tools.Most machining has very low set-up cost compared with forming, molding, and casting processes.However, machining is much more expensive for high volumes.Machining is necessary where tight tolerances on dimensions and