79 The properties of steel remain unchanged no matter how many times the steel is recycled, this is the reason why it is the world s most recycled metal. Name some common objects made of stainless steel. Iron Bauxite was discovered in 1821 by the French geologist Pierre Berthier, in Provence, southern France. ONLINE RESOURCES The extraction of iron cast iron: ghisa damping: smorzamento mild: leggero, tenue rust: ruggine slag: scoria (residuo della lavorazione dei metalli) stainless: inossidabile wear: usura wrought iron: ferro battuto 188 MeCHaNiCs FERROUS AND NON-FERROUS METALS Ferrous metals, which contain iron, have distinct properties and uses, compared with non-ferrous metals, which are iron-free. Understanding the difference between ferrous and non-ferrous metals is essential for professionals in industries like construction, manufacturing, and engineering. Ferrous metals Ferrous metals include a wide range of materials and alloys, with iron being the predominant element. The most used ones are the following. Iron is the most common metal but has limited applications as an ore, while it is widely used in alloys. Its main properties are malleability and ductility, but it is also magnetic and a good heat conductor. Steel is an alloy containing iron and other elements (up to 3%), including carbon. Its characteristics change according to the percentage of carbon: mild steel has a very high tensile strength, while high-carbon steel is very hard, for example. Other metals such as chromium and tungsten can be added to the alloy to create a large range of steels, for example stainless steel , which is extremely resistant to corrosion. Cast iron is an alloy of iron (up to 98%) and carbon (2% to 6%). According to the form of carbon it contains, it is classified as white cast iron (which offers excellent machinability) or grey cast iron (which provides exceptional wear resistance but poor ductility). It is hard and brittle and is specifically used for low-stress components (for example in engine blocks). Wrought iron is an alloy with so little carbon content that it is almost pure iron. During the manufacturing some slag is added, which gives this alloy excellent resistance to corrosion and oxidation. Wrought iron Non-ferrous metals Non-ferrous metals and alloys do not contain iron and are required for components that need to be lightweight, non-magnetic, and heat resistant. The most common nonferrous metals are: Aluminium, extracted from bauxite . It is non-magnetic, very lightweight, rust resistant, and a very good thermal and electrical conductor. It is widely used in automotive and aviation; Aluminium Copper. It is an element with excellent electrical conductivity, and thus especially used in telecommunications and electrical applications, but it is weak, so not suitable for structural elements; Titanium. It is light and very strong with extremely high corrosion resistance and a high melting point. This metal and its alloys are suitable for aerospace, food processing, chemical, and bioengineering applications.