Metals

Question 1

Measuring behaviour of metals

Answer 1

• Stress and strain
• On a graph= Y = stress and X = strain
• Increase of stress = increase of strain

Question 2

Yield Point

Answer 2

• Point object doesn’t revert to original state due to stress (aka yield strength)
• Height on y (stress/sigma) = stress point
• If goes past yield point becomes elastoplastic

Question 3

Proof Stress

Answer 3

• Used when cannot find actual yield point
• 0.1% on x axis cutting through curve of stress/strain line
• When max point on graph is reached = tensile strength (when necking happens)

Question 4

Slip

Answer 4

• Deformation from dislocation motion
• Slip from one dislocation is tiny

Question 5

Affectors of metal behaviour

Answer 5

• Grain structure
• Atom arrangement within grains
• (Smaller grains = stronger metals)

Question 6

Alloys

Answer 6

• Solid solution made of 2 metals
• Substitutional solid solution: Atoms of another element can replace existing atoms in host if similar grain size

Question 7

Interstitial Solid Solution

Answer 7

2 elements with different atoms that can fit within spaces of one another (interstices)

Question 8

Steel Production and Processing

Answer 8

• Carbon removed from iron to become cast iron
• Increased carbon content = increased strength

Question 9

Steel Production 1 - Ironmaking

Answer 9

• Smelting iron ores
• Collect raw material (iron ore and coal)
• Put in blast furnace
• Makes pig iron

Question 10

Steel Production 2 - Steelmaking

Answer 10

• Remove impurities from metal (using pure oxygen) to create crude steel
• Impurities lower strength and durability once hardened
• If impurities are not removed the material is unusable
• Molten iron is poured into a converter furnace

Question 11

Steel Production 3 - Rolling

Answer 11

• Pressure forming crude steel into finished products

Question 12

Iron

Answer 12

• Pure iron = 0% carbon - ferrite
• In iron with 0.2% carbon ferrite gaps have lines in. Lines are cementite (carbon and iron) and the gaps are ferrite

Question 13

Annealing

Answer 13

• Method of changing shape of steel
• Heating to 60% of melting temperature causing atoms to rearrange themselves allowing new grain formation