Forge welding (FOW) is an important skill to have, especially for blacksmiths. Because the process is particularly tricky, blacksmiths and welders are encouraged to practice forging in their leisure time. With regular practice, they can eventually perfect the craft. In this article, we will list down a step by step guide on how to forge weld.
What is Forge Welding?
Forge welding is the process of joining two pieces of metal together. Sounds like just any other welding process, right? But it’s not that similar. In forge welding, you can even join two different pieces of metal by heating them and then forcing them to become one. With the right technique, heat, and pressure, you can forge virtually any two metals into one.
Guide to Forge Welding
In FOW, a welder or blacksmith heats the metal first and then hammers them into one. Some even utilize presses to exert enough pressure to merge the two pieces. To get the weld just right, you need to follow a proper step by step procedure.
Heat the metals
Each metal has a different melting point. The amount of heat each piece needs varies according to metal type and its properties. There are several distinct grades of steel, and they are categorized according to their chemical structure.
Depending upon their chemical composition, the required heating temperature for each categorization of steel varies. Some ferrous metals like aluminum have really low heating points. You can easily mold them even with soft heat.
Watch out for a yellowish color when you’re heating the metals. If you continue to increase the temperature even after that, the metal will begin to oxidize. Once that happens, there is no way to fix it, and you have to switch the ruined piece with a new bit of material.
Make sure you only bring your metal to a good orange heat initially to avoid ruining it in the very first attempt.
As soon as you get the metal out of the fire, sprinkle it with flux. It serves as a low-temperature shield against atmospheric contamination. If Oxygen in the environment comes in contact with the hot steel, it can create scales on the surface and cause porous welds. Scales also prevent the metal from welding.
The Borax 20 Mule serves as the most affordable option. It works well enough with most metals while being one of the relatively cheaper alternatives in the market as well. Borax works best for all the newcomers or hobbyists. Other options include the Easy Weld and Anhydrous Borax. Both of these also serve the purpose relatively well.
If you want to weld without using a flux, you may need an Oxygen-free burner or possess the right amount of skill and expertise.
Back in the Fire
Once you have fluxed the metals, you should carefully place them again in the fire. Make sure that the heated metals do not come in contact with a direct blast of air. If that happens, some oxygen may penetrate the protective layer, which can result in scaling.
Allow the workpiece to turn a lemon yellow color. You will not be able to correctly identify the color of the metal unless you look in the fire with a pair of didymium glasses. They offer protection against the lime yellow color and from the radiation emitted during the welding process.
The metal, when at the perfect temperature, will appear shimmery and almost slippery. With the naked eye, you will not be able to identify when it is at the right temperature, so make sure to have your glasses on. If you end up overheating the workpiece, the metals will oxidize, and you will have to start over.
Remove and Secure
The next step is to remove the joint metals from the fire and secure them with a piece of metal wire. Doing so forms the primary weld, which is essential. Initially, the metal will be too hot for you to forge. Any attempt at hammering it into shape can prove disastrous, and you may end up having to repeat the entire process.
Let the two pieces join together for a bit. Doing so allows the metal to cool a little. Once you have a base to work with, you can pressurize the joint to perfection.
Hammer to Perfection
You can use either a power hammer or a hydraulic hammer to finish the forging procedure. Here is where the expertise and experience come in handy. The amount of pressure you exert has to be just right. Make sure you do not use excessive strength as that can displace the welds.
You need to use just enough pressure to force the two to coexist as one. Each workpiece requires different amounts of stress. The thickness of the metal and its chemical structure dictates the amount of strength you need to use.
Thicker metal sheets require greater strength as compared to thinner layers. The hammer blows should be firm and stable. As long as you have proper guidance and an understanding of the process, forging becomes a piece of cake.
As long as you carefully follow the steps mentioned above, you should have a solid weld in no time.
Basic Protective Equipment
Blacksmiths deal with naked flame and hammers. Therefore, safety should be of the utmost importance to them. To ensure they do not get hurt or burn themselves during the process, they should have the following safety equipment:
- Flame Resistant Overalls – they ensure that the welder’s clothes do not catch fire. As a blacksmith or a forge welder, you will be continuously exposed to high heat. You’ll be close to naked flames, which aren’t always very stable. Make sure not to step near the forge if you’re not wearing fire-resistant clothing.
- Didymium glasses – Without proper glasses, you will not be able to identify when the material has reached the desired temperature. Because blacksmiths do not use thermometers or external temperature measuring devices, they must wear proper glasses. Without them, they will not be able to see past the flames, and the metal may oxidize.
- Safety Boots – When welding, you deal with really heavy workpieces. Besides the weight, you also need to protect yourself from burns. Molten metal or hot pieces of metal may fall on your feet during the process. Especially when you begin hammering the material into the joint, make sure you have the appropriate safety boots on so that in case of an accident, your feet are well protected from the hot and heavy objects.
- Ear Plugs – In forge welding, you need to hammer the workpieces into one, which can be a noisy process. To protect your ears, you should always have earplugs at hand. Otherwise, you may end up permanently damaging your eardrum.
- Gloves – A lot of forge welders leave out the gloves when welding as they find it a hindrance in the process. However, we suggest that you always wear them whenever you’re performing any kind of welding as all welding procedures employ high heat.
For forge welding, you have to place the metal into the fire, remove it and replace it a couple of times. You’re handling an almost molten piece of metal, and you need to protect your hands. Merely using a rag is not going to provide the ideal level of protection.
If you follow the steps mentioned above to the letter and take care, and you have all the personal protective equipment with you, you can become a pro welder in no time. All you need is a little bit of practice and knowledge of the metals you’re working with.
Can Aluminum be Forge Welded?
You can weld aluminum at low heat. Most aluminum alloys are malleable for forging at around 700-900 degrees Fahrenheit. Since they are softer metals, they only require around 5 to 7 Pounds per Square Inch (PSI) to get them into shape.
Forging aluminum proves ideal for applications where a lighter weight material is needed for efficiency.
Which is Better – Cast Steel or Forged Steel?
Forged steel is stronger than cast iron or plate steel. In forged steel, the grain flow of the material is altered, and it adapts to the shape it becomes a part of. The procedure equips the material to handle impacts better than cast steel.
What is the Average Temperature Used when Forging Steel?
Forge welding requires significantly high levels of heat. Different metals require different temperatures. For steel, you will need 1150 degrees Celsius. For all other types of alloys, you need to heat the material to 360 to 520 degrees Celsius.
Does Forge Welding Increase Strength?
Yes, forging involves heating and reshaping the material. The high heat combined with pressure does significantly increase the strength of the material. When forged, steel adapts to the new shape, and the deformed particle structure substantially increases strength.