Many things throughout your home are likely made of steel. However, not all of them need to be overly strong. When steel is being used to support a structure or other heavy object, the stronger it is, the more you will be able to trust it. To strengthen steel, you need to use a specific type of heating process known as hardening and tampering. This process can be hazardous. You should always wear face protection and complete the process away from all flammable materials.
Surround a brazing heart that is large enough to hold your steel material with fire bricks.
Place the steel on the heart and heat it up with a propane torch.
Remove the steel when it gets red hot and cool it with water. Submerging the steel in water is the best method to use.
Clean the steel using an emery cloth, and place it back on the heart.
Heat it up again more slowly. This time, the steel will turn blue. After the blue color travels the length of the steel, remove it from the brazing heart.
Set the steel on top of another metal surface to slow the cooling process. The more slowly the steel cools, the harder it will become.