Deposition techniques

Powder Welding

Powder welding gives a smooth, dense coating, which can often be used with little or no further machining. The torches are simple to use – only the flame requires adjustment.

Process

Powder welding results in a smooth, dense coating with a diffusion bond to the base material. A standard oxy-acetylene torch is used, with the powder fed into the flame from an attached hopper.

The technique is typically used for glass moulds, smaller parts and repairs and is particularly suited for the repair of cast iron and machined parts, i.e. for building up edges and corners.

Typical working range

  • Deposition rate: 0.5-2.5 kg/hour
  • Deposition thickness: 0.2 - 12 mm
  • Deposition hardness: 20 - 62 HRC

Benefits

  • Simple to use: 1 step: deposit + fusing
  • Strong bonding: 0.2-12 mm thickness
  • Smoother surface

Problems with your powder welding process?

Powder welding troubleshooting
Problem Cause Solution
Deposit peels off 1. Poor preparation of the surface (oxidized or dirty surface)
2. Required surface roughness is >Ra 5
3. Too low preheating temperature
4. Too high preheating temperature
5. Too high content of S & Ti in the cast iron base

Clean the surface well
Sand blast well
Preferable >Ra10
Increase preheat
Decrease preheat

Cracks

1. Overheating
2. Too fast cooling
3. Hardened base material

Slower cooling / controlled cooling

Porosity

1. Poor preparation of the surface
2. Incorrect spray parameters
3. Poor sealing in the torch
4. Incorrect particle distribution for the torch
5. Incorrect work method with the weld pool
6. Cast iron base contains inclusions

Clean the surface well
Sand blast well
Adjust parameters
Replace seals

Courtesy of Jarvie Engineering Pty Ltd

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