Metal Properties and Processes Design and Manufacture

Alloys Alloys Alloys are mixtures of metals and/or other element combined together Ferrous alloys range from plain carbon steels, with 98% iron, to high quality steels with up 50% of other elements All other metals are non-ferrous and can be subdivided into light, heavy and refractory (heat resistant) alloys Ferrous alloys, particulary steels, form about 90% of the world’s total metal usage. Due to low cost and versatility.

Typical Alloys Brass ( Copper & Zinc) Steel (Iron & Carbon) Cast Iron (Iron & Carbon) Duralium (Aluminium & Copper) Bronze (Copper, Tin, Phosphorus) High Speed Steel (Tungsten, Chromium, Carbon, Vanadium & Molybdenum)

Forms of Metal Forms of Metal Metals are produced in a variety of forms, e.g. Rod, bar, flat strip, tube, angle and various channel sections These forms are available in a vast range of sizes because it is difficult to change the size of any piece of metal – it takes a lot of energy to cut or soften it

Applications Applications There are many different applications for metals and alloys ranging from decorative jewellery to the production of engine components. The suitability and selection of a particular metal for a product will depend on its properties

Properties of Metal Properties of Metal Elasticity – ability to return to shape after deformation Toughness – ability to withstand sudden loading (impact resistance) Brittleness – ability to be snapped easily Malleability – ability to be hammered into shape without fracturing Hardness – resistance to wear or indentation Ductility – ability to be stretched (drawn) to a reduced cross –section

Processes Processes There are many different ways in which metals can be worked. Generally it involves heating first. Molten metals can be poured into moulds. Metals can also be bent, twisted and hammered into shape. To join metals various methods can be used. They can be welded and soldered together for example. Again this uses very high heat to do this.

Metal Processes. Extrusion, Piercing and blanking Drop forging Lathe turning. Gravity and Die casting Press forming

Ferrous Metals Ferrous Metals Iron is the basis of all ferrous (iron-bearing) alloys Pure Iron is of little practical use as a material Alloys refers to the bringing together of two or more metals, often with other active elements to improve the properties and characteristics of the new material

Ferrous Alloys Ferrous alloys range from plain carbon steels with 98% iron to high alloy steels with up to 50% other elements. Alloy steels contain other elements such as chromium, nickel, etc. These elements are added in small quantities of under 5% to improve strength or hardness. Larger quantities are added to improve corrosion assistance or wear resistance at high temperatures. Elements such as lead and manganese are used to improve the machinability of the steel Examples of ferrous alloys are stainless steel, where chromium is the additive, and high speed steel (HSS), where tungsten is used It is important to know the properties of the various grades of steel so that you can select the right one to suit a particular application and method of manufacture.

Cast Iron Cast Iron Composition – iron + 3.5% carbon Properties and working characteristics – brittle/hard skin Uses – machine tools, vices

Mild Steel Mild Steel Composition – iron + up to 0.35% carbon Properties and working characteristics – malleable/ductile uniform texture Uses – nuts, bolts, screws, tubes, girders, car bodies

High Carbon Steel High Carbon Steel Composition – iron + up to 1.5% carbon Properties and working characteristics – malleable/ductile, can be hardened and tempered Uses – cutting tools, files, drills, saws, knives, hammers, taps and dies

Fine/High Quality Steel An example of some of the worlds finest tool steel.

Other pure metals These metals include: Precious metals like gold, silver, platinum Also lead, tin, aluminium, titanium, iron, mercury, copper, nickel,

Your task for today. You have to research; 2 Alloys 6 Pure metals. For each of them you need to record a list of each of their characteristics. This needs to include, colour, workability, typical uses and applications.