Metals Flashcards
Name the stock forms of ferrous metals…
Sheet, bar, tube and angle
What is a ferrous metal?
Name 2 qualities…
Ferrous metals are iron based metals #1 Magnetic #2 Rust
What happens as you increase the carbon content of iron?
The higher the carbon content the more brittle and hard it becomes.
Mild steel; What percent is carbon? What are it's properties? What are it's positives? What are it's negatives?
Carbon; 0.25%
Properties; Ductile, tough, soft (can be bent)
+ (relatively) Easy to work
- Rusts easily (more than other steels)
What are possible uses of mild steel?
Car body panels
Nuts and bolts
White goods
Medium carbon steel;
What percent is carbon?
What are it’s properties?
Can it be tempered?
Carbon; 0.5%
Properties; quiet ductile
It can be tempered
(It’s an Engineers favourite)
What are possible uses of Medium carbon steel?
Springs
High carbon steel;
What percent is carbon?
What are it’s properties?
Can it be tempered?
Carbon; 1.5%
Properties; not very ductile
It can be tempered
What are possible uses of High carbon steel?
Carpentry tools
Cast iron;
What percent is carbon?
What are it’s properties?
What are it’s negatives?
Carbon; 3.5%
Properties; not ductile, hard (inflexible), brittle
Shatters when dropped
What are possible uses of cast iron?
Vices
Clamps
Engines
What is a non-ferrous metal?
What are 2 basic qualities?
A metal that contains no iron #1 Non magnetic #2 Doesn't rust
Aluminium; What does it come from? Properties? Positives? Negatives?
Origin; bauxite (difficult to extract)
Properties; malleable, ductile, very conductive (heat & electricity), light, self protects
+ 100% recyclable (melts 660oc)
- Expensive, has to be extracted using electrolysis
What are possible uses of aluminium?
Aircraft, expensive car bodies and castings (add silicon)
Copper;
Properties?
Positives?
Malleable, ductile, very conductive (heat and electricity)
+non toxic
What are possible uses of copper?
Plumbing
Give some positives and negatives of Gold, Silver and Platinum…
What are possible uses?
+ Non corrosive
+ Hypo-allergenic
-Expensive
(Gold; very good conductor)
Jewellery
(Gold can also be used for SIM cards)
Zinc;
Properties?
Uses?
Has a low melting temperature; 850^, non corrosive
Plating for ferrous metals
Stock forms of non-ferrous metals?
Sheet, tube and ingot
What metal can be used for white goods?
Mild steel (also used for car bodies & nuts and bolts)
What metals could be used to make a ring?
Gold, platinum and silver
Why high carbon steel used in carpentry tools?
Very hard (1.5% carbon) it can be sharpened to a very sharp edge
What metal can be used to make springs?
Medium carbon steel (0.5% carbon)
Why might a clamp break when dropped?
It is made from cast iron which is 3.5% carbon so is very brittle and not ductile; shatters
Why is copper used for pluming?
It is malleable; pipes need to be bent, and is non toxic
What might be used to plate the outside of a ferrous metal? And why?
Zinc; it is non corrosive so protects the ferrous metal which would rust
Why would you use mild steel for a car?
Mild steel is a malleable material which means it can be press formed into the shape required. It can also be spot welded; which is one of the main ways of constructing car body panels.
Mild steel sheet will crumple not shatter; crumple zones.
You can also apply variety of finishes for aesthetics.
Why would you use Aluminium in a drinks can (4)
It is malleable; allows the can shape to be cupped and deep drawn in production. It’s also available in thin sheet form for punching the blank shape.
Aluminium is a non-toxic material (chemical resistant) won’t contaminate the drink.
It’s low melting point, makes it easy to recycle.
It’s widely available which is required for mass
production.
How would you finish a car? (what finishes literally)
Galvanise, prime, undercoat, overcoat, lacquer
What 2 ferrous metals can you temper?
What is tempering?
Medium carbon steel & high carbon steel
Heating the metal to a controlled temperature and quenching in a controlled liquid (usually oil)
What is annealing?
Heating the metal then naturally letting it return to it’s original state
What is hardening?
Heating the metal until red hot then instantly quenching
What does it mean to work harden?
The more you hit the metal the harder it gets
Ferrous metals rust, non ferrous metals…
Oxidise; self protecting!
Why is copper used as electrical wiring
Copper is be used in the production of
electrical wiring, as it is a very good electrical conductor.
Copper is extremely ductile, meaning it can be drawn into a wire without fracture.
What is galzanising?
The application of a coat of zinc
