Manufacturing Processes (Joining) - Week 5

Question 1

Why are very few components made in one piece?

Answer 1

It is generally inconvenient, unsatisfactory or simply impossible

Question 2

What is fusion welding?

Answer 2

The melting of solids, allowing them to flow and “fuse” together; a molten filler material may also be introduced into the gap

Question 3

What materials can be fusion welded?

Answer 3

Metals, thermoplastics and glasses can be fusion welded
High energy inputs are required for metals, giving rise to component distortion, oxidation and microstructural changes

Question 4

What type of welding is used to join thick sections?

Answer 4

Gas and arc welding

Question 5

What type of welding is used to join thick and thin sections?

Answer 5

Laser and electron beam welding

Question 6

What is Electrical resistance welding?

Answer 6

A common process for joining thin sheet such as car bodies and white goods

Question 7

What is oxy-acetylene welding?

Answer 7

• A process that uses a fuel gas and oxygen to weld metals
• Pure oxygen is used to increase the flame temperature to allow localized melting of the workpiece material in a room environment

Question 8

Explain the process of welding metal using a torch?

Answer 8

• Welding metal results when two pieces are heated to a temperature that produces a shared pool of molten metal
• The molten pool is generally supplied with additional metal called filler. Filler material depends upon the metals to be welded

Question 9

Does solid phase welding involve an external heat source?

Answer 9

Solid phase techniques do not involve an external heat source to melt the materials. They rely upon pressure and modest heat inputs

Question 10

What is friction welding used for?

Answer 10

Friction welding (rotational or linear) can be used for metals and thermoplastics

Question 11

What is diffusion welding?

Answer 11

• Diffusion welding is a solid phase welding process by which two metals can be bonded together
• Diffusion involves the migration of atoms across the joint, due to concentration gradients
• The two materials are pressed together at
  an elevated temperature usually between 50 and 70% of the melting point

Question 12

What does forge welding involve?

Answer 12

Forge welding involves mechanical force and heating