Manufacturing processes book (METALS)

Ferrous

• Mild Steel – Carbon content of 0.1 to 0.3% and Iron content of 99.7 – 99.9%. Used for engineering purposes and in general, none specialised metal products.

• Carbon steel – Carbon content of 0.6 to 1.4% and Iron content of 98.6 to 99.4 %.  Used to make cutting tools such as drill bits.

• Stainless Steel- Made up of Iron, nickel and chromium. Resists staining and corrosion and is therefore used for the likes of cutlery and surgical instrumentation.

• Cast Iron – carbon 2 – 6% and Iron at 94 to 98%. Very strong but brittle. Used to manufacture items such as engine blocks and manhole covers.

• Wrought Iron – Composed of almost 100% iron. Used to make items such as ornamental gates and fencing. Has fallen out of use somewhat.

Non Ferrous

• Aluminium – An alloy of aluminium, copper and manganese. Very lightweight and easily worked. Used in aircraft manufacture, window frames and some kitchen ware.

• Copper – Copper is a natural occurring substance. The fact that it conducts heat and electricity means that it is used for wiring, tubing and pipe work.

• Brass – A combination of copper and zinc, usually in the proportions of 65% to 35% respectively. Is used for ornamental purposes and within electrical fittings.

• Silver – Mainly a natural substance, but mixing with copper creates sterling silver. Used for decorative impact in jewellery and ornaments, and also to solder different metals together.

• Lead – Lead is a naturally occurring substance. It is heavy and very soft and is often used in roofing, in batteries and to make pipes.

Alloy
-a metal made by combining two or more metallic elements, especially to give greater strength or resistance to corrosion.

Iron- A chemical element which is crystalline in nature. To metalworkers, pure iron is relatively a soft metal so it is combined with other metals.

Steel-Simple steel is an alloy of iron and carbon containing no other element. Commercial steels, however, are plain carbon steels containing manganese and small quantities of silicon, phosphorus, sulfur, and traces of other elements. Its carbon content is from a few hundredth of a percent to 1.4 percent. Plain carbon steel seldom contains more than 1.4 percent carbon. There are, however, steels which contain up to 2.0 percent. Aside from carbon, various other elements are added to give steel different properties suitable for different applications:

Aluminum Alloys- A very light metal which is gradually taking the place of iron in many application. This metal is malleable, ductile, and a good conductor of heat and electricity. It is a cheap substitute to the more expensive copper in many electrical installations.

Magnesium Alloys- Magnesium alloys are mixtures ofmagnesium with other metals (called analloy), often aluminium, zinc, manganese, silicon, copper, rare earths and zirconium.

Titanium Alloys- Titanium alloys are metals that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness (even at extreme temperatures). They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures.

Zink Alloys-Used extensively in dry cells and batteries. It is used as sacrificial anodes attached to the hulls of sea-going vessels and in coating iron to produce galvanized iron.

Copper Alloys-Another very useful seddish-brown metal. It is malleable, ductile, and is next to silver in electrical and thermal conductivity. It is extensively employed in many electrical applications. When copper is alloyed with zinc, brass is produced. When alloyed with tin, bronze is produced.

Nickel Alloys-  nickel alloys are used extensively because of their corrosion resistance, high temperature strength and their special magnetic and thermal expansion properties.

Lead and Tin Alloys-Very malleable and can be rolled into very thin sheets. It is used in coating insides of pipes used for conveying drinking water. It is also plated insides cans used to conserve foodstuff due to its high resistance to tarnishing. One of the densest metals. It is soft and can be cut with a knife. A two millimeter thick sheet may be bent or straightened with bare hands. It has been used extensively in plumbing but it being replaced by other metals. One popular application is the galvanized iron roofing, where lead washers are used.

Precious Metals- gold, silver, and platinum.