Unit R014 - Engineering Manufacture - Topic Area 2 - Retrieval B

Engineering Metals -

Metals used by engineers are either a pure metal or an alloy. Select the definition of an alloy.

• A metal which is extracted from the ground and used with no additional metals added.

• A material which once heated is unable to be recycled.

• A metal which is a mixture of two or metals joined together.

• An alloy is found on cars and used to support the tyre whilst looking nice.

Answer explanation

Alloys are created in order to take advantage of the differing properties of the different metals.

An alloy will have properties and characteristics of the metals used in its chemical make up.

For example stainless steel is a steel alloy that primarily consists of iron. The addition of chromium however in the alloy allows for the strength and durability of iron whilst preventing the adverse corrosion that comes with iron based metals.

Engineering Metals -

What pure metal is used here?

• Copper

• Brass

• Bronze

• Gold

Answer explanation

Pure metals are used in engineering but not as obviously as alloys.

Copper, silver, aluminium and gold are often used in there pure form where electrical conductivity is important due to their low electrical resistance.

The same pure metals are also used in heat transfer applications. For example pure copper is used by welders. They will put a piece of pure copper close to the area to be welded. The copper will draw the heat away from the joint and help to reduce warping and deformation.

Pure metals are also widely used in the electroplating process. Metals such as chromium, nickel, gold, silver and zinc being common.

Engineering Metals -

Select the list of ferrous metals.

• Cast Iron

  Low Carbon Steel

  High Carbon Steel

  Stainless Steel

• Zinc

  Tin

  Aluminium

  Titanium

• HDPE

  PVC

  HIPS

  Nylon

• Carbon Fibre

  Glass

  Concrete

  GRP

Answer explanation

Ferrous metals are any metal that includes iron in its chemical composition.

Engineering Metals -

Select the list(s) of non ferrous metals.

• Brass

  Bronze

  Gold

  Silver

• Aluminium

  Titanium

  Zinc

  Chromium

• Stainless Steel

  Mild Steel

  High Carbon Steel

  Low Carbon Steel

• Glass

  Kevlar

  HIPS

  PVC

Answer explanation

Non ferrous metals include all of the pure metals on the period table with the exception of iron.

Non ferrous metals are typically alloyed with other metals as they can be excessively malleable and ductile in there pure form.

Engineering Metals -

Aluminium when used in a more structural setting, such as this car chassis, is often alloyed with what?

• Silver

• Magnesium

• Tungsten

• copper

Answer explanation

Pure aluminium would be far too soft. Adding magnesium greatly increases the strength of the overall alloy.

Silicon is also added commonly. The silicon greatly improves the fluidity of the aluminium making the casting of aluminium far more successful.

Engineering Metals -

Steels typically have good ​ (a)   properties. In particular good ​ (b)   strength. Regular steels have a relatively small ​ (c)   content, making them ductile and ​ (d)   . This means they can be worked into different shapes easily without ​ (e)   .

• strength
• tensile
• carbon
• malleable
• fracture
• hard
• glass

Engineering Metals -

Cast irons typically have high carbon contents, ranging between 2% and 4%. What properties do cast irons have?

• Low tensile strength

• Brittleness

• High Compressive Strength

• Good Elasticity

Answer explanation

These properties listed in the question are generalised and the actual properties all depend on the alloy used in the chemical make up of the cast iron.

For example a cast iron with 2% carbon will have reduced brittleness in comparison to a 4% carbon version.

Also cast iron's with increased silicon content can also have good machinability and slightly less brittleness.

Engineering Metals -

Match the product to the most appropriate metal.

• Stainless Steel

• 
• Bronze (alloy)

• 
• Aluminium Alloy

• 
• Copper

• 
• High Carbon Steel

• 

Engineering Metals -

Match the product to the metal.

• Cast Iron

• 
• Zinc

• 
• Brass

• 
• Mild Steel

• 
• Gold

• 

Answer explanation

The bolt and HDMI lead are not made from zinc and gold.

They will be made from a cheap inferior metal such as steel and then coated in zinc or gold.

The zinc will stop the bolt from corroding and the gold will improve the electrical connectivity of the HDMI lead.

Engineering Metals -

Typically non ferrous metals and there alloys have what properties?

• Corrosion Resistance

• Machinability

• Malleability

• Brittleness

• Ductility