soldering

Question 1

what is welding?

Answer 1

Welding: Process of fusing two or more metal parts through the application of heat, pressure, or both, with or without using a filler material

Question 2

what is soldering?

Answer 2

Soldering: Process of joining two or more metal components by heating them to a temperature below their solidus temperature, and filling the gap between them using a molten metal whose liquidus temperature is below 450oC. Bonding occurs by capillary action, with no change to the components’ dimensions

Question 3

what is brazing?

Answer 3

Brazing: Same as soldering, but the liquidus temperature of the molten metal that fills the gap between the two components is above 450oC

Question 4

what is soldering flux?

Answer 4

Flux in Latin means flow
Soldering filler metals are designed to melt, wet the surfaces of the parts to be joined, and flow across clean metal surfaces. The flux is to eliminate any oxide coating on the metal surface when the filler metal is molten and ready to flow into place.
Fluxes have temperature ranges for optimal activity in breaking down oxides

Question 5

what are the three types of soldering flux?

Answer 5

1. Surface protection: covers the metal surface and prevents access to oxygen so that no oxides can form.
2. Reducing agent: reduces any oxide present and exposes clean metal.
3. Solvent: Dissolves any oxides present and carries them away.

Question 6

what is soldering (brazing) filler metal, what shoud it be like?

Answer 6

Must be compatible with the oxide free substrate metal
Does not necessarily have a similar composition to the substrate metal
Compatibility consists of three primary properties:
1. Sufficiently low flow temperature
2. Ability to wet the substrate metal
3. Sufficient fluidity at the flow temperature

Question 7

what are the heat sources for soldering?

Answer 7

Hydrogen (2660oC - 2362 kcal/m3)
Natural Gas (2680oC - 8898 kcal/m3)
Acetylene (2850oC - 21221 kcal/m3)
Propane (3140oC - 12884 kcal/m3)

don’t memorize it’s just to show different energy sources

Question 8

what are the technique considerations for soldering, the procedure?

Answer 8

1. Cleaning and preparing the surfaces to be joined
2. Assembling the parts to be joined
3. Preparing and fluxing the gap surfaces between the parts
4. Maintaining the proper position of the parts during the procedure
5. Controlling the proper temperature
6. Controlling the time to ensure adequate flow of solder and complete filling of the solder joint

Question 9

what is the optimal gap between the parts you are trying to solder?

Answer 9

Never been defined.
If the gap is wide, the joint’s strength will be controlled by the strength of the filler material.
If the gap is narrow, the strength will be be probably limited to flux inclusions, porosity caused by incomplete flow of the filler material, or both.
Inclusions or porosity can lead to distortion if any heating, such as porcelain application, takes place after the soldering operation