What is Forge Welding? Forge welding process is a solid state welding process in which two metals are heated at a high temperature and then they are hammered together to form a single strong joint.
Forge welding is the oldest and simplest method of welding the metals.
By using a forge welding process, similar as well as dissimilar metals can be joined with each other.
Well, this was just an introduction. Now, let’s discuss the entire forge welding process step by step.
Forge welding process (6 steps)
Forge welding process is mentioned below in 6 steps.
- Step 1: Prepare the materials
- Step 2: Adding flux to the metal pieces
- Step 3: Heat the metal pieces in a furnace
- Step 4: Watch out for lemon yellow color of metal
- Step 5: Remove the metal pieces from furnace
- Step 6: Forge the metal pieces using a hand hammer or machine
Detailed explanation of forge welding process (How forge welding works?)
First of all the parts which are to be welded are heated to a plastic condition.
The heating of these metal parts is done in any furnace suitable for heating the metal.
After the metal parts are heated to their plastic condition, they are hammered together.
This hammering can be performed by hand or machine.
In the above image, you can see the hammer used for forging operation.
While the below image shows you the trip hammer which performs hammering action automatically.
This type of machine forging is suitable for the forge welding of large workpieces.
During the forge welding process, there is a possibility of oxide formation on the surface of the metal.
So the surface should be perfectly cleaned before performing forge welding operation, otherwise the joint formed will not be strong.
In order to remove the oxide scale, few methods are used.
The oxide scale can be heated to a higher temperature so that it melts out and in this way the oxide scale is separated from the metal to be welded.
To melt the oxide scale, its melting temperature should be lowered.
This can be done by adding a compound which itself melts at a very high temperature but forms a lower melting mixture with oxides.
The other way to remove oxide is by using the forge welding flux.
Borax is put between the two surfaces which are to be forged welded.
The main function of borax is to dissolve the oxide scale and the resultant solution will be such that it can be easily squeezed when forging pressure is applied.
The melting point of borax is 1365 °F and the metal parts which are to be welded are heated at the temperature above this value.
Thus the borax dissolves the oxides and the solution remains in the liquid state when the weld metals are heated. And when the forging pressure is applied, the liquid solution containing oxide scales squeezes out.
Forge welding process is a slow process and the quality of the weld is not very high.
Having discussed the forge welding procedure, now let’s see the advantages and disadvantages of forge welding.
Advantages of forge welding
The advantages of forge welding process are mentioned below.
- Forge welding process is simple and easy.
- The parts of different shapes can be welded using forge welding.
- Filler metal or filler rod is not required during the process.
- For welding of small workpieces, it does not require any complicated machinery. The forge welding can be easily done by a forge hammer.
- Similar as well as dissimilar metals can be welded using a forge welding process.
Disadvantages of forge welding
The disadvantages of forge welding process are mentioned below.
- This process is mainly suitable for welding of low carbon steel.
- Skilled welder is required for forge welding operations.
- Forge welding process is slow as compared to other welding processes.
- The weld metals may get contamination from the coke used for heating the metal.
- This process is not economical for mass production as it consumes more time.
- Welding of larger parts requires a large furnace and large machines for hammering, which makes the process very costly.