Summary

This document provides an overview of various ferrous and non-ferrous metals, including their properties and uses. It also describes alloys and their applications, examples include stainless steel, brass, and duralumin.

Full Transcript

Metals Theory You need to know about the following for metals theory: Ferrous metals including: Non ferrous metals low carbon steel/mild steel including: cast Iron aluminium medium carbon/tool steel copper tin...

Metals Theory You need to know about the following for metals theory: Ferrous metals including: Non ferrous metals low carbon steel/mild steel including: cast Iron aluminium medium carbon/tool steel copper tin zinc Alloys including: brass stainless steel duralumin Ferrous Metals Contain iron, ferrite, or other substances e.g. carbon steels Magnetic (most) What is the chemical symbol for iron in the Periodic Table? Examples: Cast iron Low Carbon Steel (Mild steel) (alloy of iron and 0.05-0.3% carbon) High carbon steel (alloy of iron and 0.6 – 1.5% carbon) Properties and uses of ferrous metals Cast iron Description: Dull, varying shades of grey depending on type, rough texture unless machined, less prone to rust than pure iron due to carbon content of 2.4 – 4%, rigid under compression. Cannot be bent or forged. Characteristics/properties: Hard but brittle in thin sections, easily cast into complex shapes, some types are hard to machine Uses: kitchen pots and pans, machine bases and bodies, manhole covers, Properties and uses of ferrous metals Low Carbon/ Mild steel Description: Bright grey in colour, smooth texture, rusts easily so needs to be coated with a surface finish or galvanised Characteristics/properties: High tensile strength, ductile, tough, fairly malleable, easily machined, formed, brazed or welded Uses: Nails, screws, nuts and bolts, car bodies, construction – girders for supporting buildings and other structures In packaging it is used in the form of tinplate (cold rolled steel sheet coated with a thin layer of tin to prevent corrosion). Thin sheets of steel are lightweight and can be easily moulded to make food and aerosol cans Properties and uses of ferrous metals Medium Carbon steel Description: Very similar to mild steel but does not rust easily, very smooth texture Characteristics/properties: Less ductile and harder than mild steel due to a higher carbon content, very hard-wearing and keeps an edge well (does not get blunt easily) Uses: Garden or workshop tools, blades, scissors, wood and metal cutting tools Recycling ferrous metals More environmentally friendly Takes 75% less energy to recycle steel than to make it from iron ore (the ore would have to be heated to a very high temperature to produce steel) Very easy to sort using electromagnets Approx 51% all steel packaging is recycled Non-ferrous metals Do not contain iron They are not magnetic Examples: Aluminium (pure metal) Tin (pure metal) Copper (pure metal) Zinc (pure metal) Aluminiu m from bauxite ore Produced Large amounts of energy are used to extract alumina from bauxite ore and turn it into aluminium Can be easily recycled over and over without spoiling (100% recyclable) Recycling is more sustainable than converting from ore (less energy used, reduction in use of finite resource) Properties and uses of Non-ferrous metals Alumini um Description: Light grey, can be polished to a mirror finish but often has a matt, brushed finish Characteristics/properties: Light weight, soft, ductile, malleable, good conductor, corrosion-resistant but can be difficult to weld Uses: Pots and pans, sports car body panels, bike frames, aircraft bodies, foils, packaging, cans, utensils, wire Properties and uses of Non-ferrous metals Tin Description: Silvery white, often plated onto steel with a silvery finish Characteristics/properties: Soft, ductile, malleable, corrosion- resistant, low melting point, good electrical conductor Uses: Used in the production of food cans – plated to the surface to preserve the contents, soft solder for electrical circuits, alloyed with copper to form bronze Properties and uses of Non-ferrous metals Copp er Description: Light reddish brown, polishes well, oxidises to a green/silvery colour that does not corrode the material Characteristics/properties: Malleable, ductile, good conductor, corrosion-resistant, easily joined by soldering Uses: Plumbing supplies, printed circuits, electrical wire, bespoke roofing and guttering Properties and uses of Non-ferrous metals Zinc Description: Silvery grey with a bluish-white hue, matt finish Characteristics/properties: Fair electrical conductivity, malleability and ductility; however, all are improved when alloyed with another metal Uses: Mainly used to galvanize steel to prevent rusting such as galvanised screws, easily Alloys Alloys are a mixture of 2 or more pure metals that are are designed to have enhanced properties Examples: Stainless steel (alloy of carbon steel with 13% chromium and 8% nickel) Brass (alloy of 65% copper, 35% zinc) Duralumin (4% copper, 1% magnesium and manganese) Properties and uses of Alloys Stainless steel Description: Silver hue that can be polished to a mirror finish, resists rust well Characteristics/properties: A ferrous alloy with chromium, nickel and manganese. Hard but very smooth. Very difficult to shape, saw, finish and weld. Uses: Cutlery, kitchen and medical equipment. Properties and uses of Alloys Duralumin Description: Very similar to aluminium in looks Characteristics/properties: Very lightweight/strong, ductile, malleable, excellent machining characteristics. Disadvantage – it work hardens (can become hard and brittle and will fracture/split over time – in an aircraft this would be catastrophic) Uses: Aircraft parts, vehicle parts (due to excellent strength to weight ratio) Properties and uses of Alloys Bras s Description: Yellowish gold, polishes well and oxidises to a dark antique brown Characteristics/properties: A heavy alloy of copper and zinc that is malleable, easy to cast and machine and naturally has low friction Uses: Musical instruments, plumbing fitments, door handles, boat fittings, ornaments Properties and uses of Alloys High Speed Steel Description: Varies depending on the combination of metals alloyed with the steel Characteristics/properties: Able to withstand the high temperatures created when machining at high speed, keeps its cutting edge well. Uses: Cutting tools such as drill bits, mill cutters, taps and dies Metals in Commercial Packaging Advantages: Added security – tamper proof (evidence is easy to see) Containers can be made in variety of standard sizes Can be embossed or de-bossed Can print onto metals directly or add label

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