Joining Technology - 230420

Question 1

Friction welding

Answer 1

Rotational parts, no external heat applied, ceramic vs. Aluminum, steel vs. Ceramic, material mix
No liquid phase.
A lot of scattering in the weibull distribution, makes it unfeasible for industrial applications (not a good quality assurance). Reibschwei?

Question 2

Applications friction welding

Answer 2

2-150 mm cylindrical parts or tubes, screws

Question 3

Friction stir welding

Answer 3

There is a pin in the joint of two flat parts and the pin produces heat and it mixes the two materials together. Displlacemnet controlled or force controlled.
Aluminum sheets up to 0.5-25 mm, aluminum cast and sheet are weldable together. Copper is also possible. Tool is standard steel.
For steel it’s not very used, since it is too tough, welding is too slow and the tool needs to be thermal treated.
Not a widely used technology.

Question 4

Advantages

Answer 4

No fused-on spatters, fume or dust.
No inert protective gas.
Very good mechanical behavior of the welds.
Fundo wheels, save 2-4 kg in each wheel.

Question 5

Welding phase

Answer 5

Welding - Austenite
depending on the cooling rate you get different combinations of phase

Question 6

Dependence of the absorption of the light energy vs. wavelength

Answer 6

High wavelength – usually low absorption in steel
low wavelength - big

Question 7

What materials can have laser ight amplification effect

Answer 7

CO2, He

Question 8

Disc laser

Answer 8

Multiple internal reflection that increases the power of the laser, optical resonance

Question 9

Interaction time laser - material

Answer 9

Hardening the most, welding second most
engraving the least

Question 10

Principle of thermal conduction welding

Question 11

Advantages laser welding

Answer 11

• Small heat affected zone.
• High welding penetration.
• Automation.
• Good reproducibility.

Question 12

Laser welding imperfections

Answer 12

Pores, cracking, splatter, incomplete fusion