✅3.6 - Metals Flashcards
What is a metal ore?
A rock containing a metal, or a metal compound, in a high concentration to make it economic to extract the metal
Name two iron ores and state what both of them contain
Magnetite and haematite contain iron oxide
How is iron extracted from an iron ore?
Blast furnace
What do you put in the thing used to extract iron?
Put iron, coke and limestone in the blast furnace
What is the source of aluminum?
Bauxite, which is a hydrated form of aluminium, extracted by open-casting and crushed and dried
How is aluminium made?
An expensive electrolytic process is needed for production, which consumes large quantities of electrical energy
What is an alloy?
Mixture of two elements, one of which is a metal
Why are alloys more useful? (3)
- They are often harder than the metal they contain because they have atoms of different sizes which distorts the regular arrangements and makes the layers difficult to slide.
- Tensile strength increases
- Malleability and ductility is reduced
What are stainless steels a mixture of?
Iron + carbon + chromium
What is work hardening?
An increase in the hardness of the metals as a result of working them cold. It causes a permanent distortion of the crystal structure
Two types of metals
Ferrous and non-ferrous
Properties of metals (7)
Brittleness, ductility, hardness, elasticity, malleability, toughness, work hardening
Properties of ferrous metals
They contain iron and they can conduct heat and electricity, and also have high melting points
What happens if oxygen reacts with ferrous metals?
Corrode and rust unless they are treated to prevent it
Cast iron properties
Brittle and corrodes by rusting
Cast iron uses
- Casting
- Manhole covers
- Car brake discs
What is stainless steel a mixture of?
Alloy of iron, chromium, magnesium, nickel
Uses of stainless steel
- Cutlery
- Kitchen equipment
- Sanitary and surgical equipment
What is high speed steel (HSS) made of?
Alloy of iron, tungsten, vanadium, and chromium
Uses of high speed steel (HSS)
- Drill bits
- Lathe tools
- Milling cutters
What is mild steel made of?
Alloy of iron with very little carbon
What are the uses of mild steel?
- Engineering and construction material
- ## Nuts, bolts, car body panels
What are the uses of high carbon steel?
- Cutting tools
- Ball bearings
- Screwdrivers
- Hammers and saws
What are non-ferrous metals?
Metals and metal alloys that do not contain iron
What are the uses of lead?
- Roofing
- Construction
- Casting
- Lead acid batteries
What are the uses of tin?
- Coating on food cans
- Tin foil
What are the uses of zinc?
- Coating on screws, nails, nuts, and bolts
- Weatherproof steel (galvanising)
What are the uses of duraluminium?
- Aircraft construction
- Boat building
- Car manufacture
What are the uses of aluminium?
- Saucepans
- Cooking foil
- Window frames
- Bicycles
What is brass made of?
Alloy of copper and zinc (CuZn)
What are the uses of brass?
- Decorative metals (handles, ornaments, musical instruments)
What are the uses of copper?
- Plumbing
- Cookware
- Electrical fittings
- Roof coverings
What is the result after annealing?
The metals become softened and can be cut and shaped more easily than if it had not been
How does annealing work?
it is a process that is often undertaken after a piece of material is work hardened. When a metal is annealed, it is heated to a specific temperature and then cooled - it does not involve working with the material in a hot state. Because heating and cooling changes the molecular structure of the material, causing it to soften.
What is tempering?
It is usually perfomed after hardening, to reduce excess hardness, and is done by heating the metal to some temperature below critical point for a certain period of time, then allowing it to cool in still air
What are the steps of tempering?
- Metal hardened (cherry red) quench in water
- Clean/polish surface wet and dry paper
- Heat - colours flow to the end of the water
- When desired colour reaches end, quench in water
- Metal is tempered
idk what this means tbh
How does case hardening of mild steel work?
It hardens 0.05mm of the surface of the metal only, which uniformly hardens the material throughout.
What is an advantage of case hardening of mild steel?
It leaves the core unhardened, meaning that it is able to retain its malleability and flexibility so that it is easy to work with
