Are you trying out your first sword? Or have you had many failed attempts at forging a sword simply because you could not get the right temperature? Blacksmithing involves heating and reheating and heating and so smiths often need to know the temperature of the steel as they work on it. This is for a variety of reasons like annealing, hardening and tempering. When forging a sword, it usually involves several heating processes in a forge. Normally, the smith’s forge is just a huge super-hot oven. Most conventional smiths prefer to use coal forges while their contemporary counterparts favor the gas or electric forge. Whatever the case, they all desire the same result; which is to heat the steel to the perfect temperature for shaping the sword. So, you decide which forge you prefer to use.
Getting the right temperature to forge your sword really depends on the kind of steel you have chosen to use. Also, colors are a good way to determine temperature of steel. I will share some basic tips to help you get the perfect temperature.
1. When working with modern homogenous steel, I would suggest you go with the temperature advised by the manufacturer. For O1 and W2, you can forge between 1500F and 2100F, as you get closer to the shape you want, you can forge around 1500F to 1600F. Still it depends on you and what you are trying to achieve. If you are fine-tuning the shape, you could still go lower to between 1100F – 1300F.
2. Another tip is to watch the color of the steel. Orange to yellow hot is a good temperature for moving the steel. Once it becomes red, it’s time to reheat. Generally, steel becomes red hot around 1200-1500F and becomes orange at about 1800F. Most steel alloys fall within these ranges too. If the steel is not hot enough and is closer to blue, hammering can shatter it.
3. For roughing, it is advisable to stay between 1500F and 1800F. At this point, the steel is pretty much just smoking and forging drops to a red-orange color. Most of the moving of the steel should be done at a higher temperature and the temperature should be reduced when it’s time for corrections and straightening before being put back in the forge.
4. When shaping the bevels, it’s best to begin at 2000F and hammer with lighter blows as the steel cools down to around 1100F. At this point, it is still very hot, but not glowing. The color will be around dark cherry to black. It’s easier now to hammer marks and make the surface more even. It’s advisable to peen the surface and try to refine the shape until the steel is gray, because at this point, you can clearly see the surface of the hammer marks and lines of the sword.
These tips are invaluable and very easy to follow. Hope this helps when next you are attempting to forge a sword.