Content

• Part 2 of 3: Hardening the metal
• Part 3 of 3: Oven Vacation
• Warnings
• What do you need

1 Light a propane blowtorch to use it as a heat source. Unscrew the gas valve near the burner base. Bring the igniter to the end of the nozzle and squeeze it to strike a spark. After several attempts, the gas jet should ignite. Screw on the gas valve so that the flame comes out in a small cone.

• A larger flame produces less heat, while a smaller flame produces a higher temperature.
• The blowtorches heat up a small area. If you need to heat a large enough part, you will need a metallurgical furnace (forge).

Security measures

When working with a blowtorch be sure to wear safety glasses and gloves.

Before using the blowtorch, read the instructions carefully and follow safety precautions.

2 Keep the metal directly under the flame. Clamp the steel piece into metal tongs and grasp them with your non-main hand to keep away from the flame. If you do not have the correct tongs, place the metal on a sufficiently wide, heat-resistant surface. Take a blowtorch with your dominant hand and warm up the entire steel surface first before focusing on the area you want to harden (such as the tip of a screwdriver or the tip of a chisel).

• Wear thick gloves to avoid scalding.
• Work on a metal or steel surface such as an anvil to prevent fire.

3 Wait for the steel to turn cherry red. Watch how the color of the steel changes when heated. The steel will be ready for hardening when it turns a bright cherry red color, that is, it warms up to about 750 ° C.

• The actual temperature of the steel depends on the carbon content. The more carbon the steel contains, the longer it will take to heat it.
• Another good way to check if the steel is ready for hardening is to see if the magnet sticks to it. If the magnet is not attracted, then the steel is hot enough.

Part 2 of 3: Hardening the metal

1. 1 Pour enough water or oil into a heat-resistant container so that the part can be completely submerged in the liquid. A coffee can or the like can be used as a quench tank.Pour water or vegetable oil into the container so that there is 5-8 centimeters between the liquid level and the top edge. The oil or water should be at room temperature.
   • Water is good for quick quenching of hot metal, but the thin steel part can bend or crack.
   • Vegetable oil has a higher boiling point, so the steel will cool more slowly, which will reduce the risk of cracking. However, if the hot metal is immersed too quickly in the oil, it may splatter and cause a fire.
2. 2 Transfer the hot steel directly to the quenching medium. Using tongs, transfer the steel part to the quench tank while the metal is still hot. Step back when submerging metal in water or oil, as the liquid may release steam or spray. Continue to hold the part with your tongs so that you do not have to remove it from the bottom of the container later.
   • When hardened, the steel quickly cools and hardens.
   • Before hardening steel, wear thick gloves and a face shield to prevent splashing liquid from spilling onto bare skin.
   • Keep a Class B fire extinguisher nearby in case of fire.
3. 3 Remove the part from the quenching medium when the liquid stops bubbling. When the steel cools down, the water or oil around the part boils. Keep the part completely submerged in the quench medium until the liquid stops boiling and emitting steam - this will take no more than a few minutes. Then place the hardened part on a work surface.

   Hardening not only hardens steel, but also makes it more brittle, therefore do not drop a hardened part or try to bend it.

   
   
4. 4 Wipe off any remaining quenching medium from the surface of the steel. Water is corrosive to steel and can damage metal if left on the surface. Wipe the part well with a rag without removing gloves.

Part 3 of 3: Oven Vacation

1. 1 Preheat oven to 190 ° C. Wait for the oven to warm up to the correct temperature before placing the steel part in it. If the part does not fit in the oven, you will have to use a blowtorch for tempering.
   • Anneal the metal in a small toaster oven if the part fits in it. In this case, you do not have to occupy the oven, and you can use it for other purposes.
2. 2 Place the steel piece in the oven for three hours. Place it directly on a wire rack or baking sheet. Wait for the metal to warm up properly in the oven. When tempered, the steel softens slightly and becomes less brittle.

   If you are forced to use a blowtorch, aim the tip of the flame at the area you want to harden. Keep heating the steel until until you notice that the metal takes on a blue tint. This indicates that the steel has been tempered.

   
   
3. 3 Turn off the oven and leave the part in it overnight. After holding the metal for three hours in a hot oven, let it cool slowly. As a result, the steel will remain in equilibrium and retain its hardened structure. Remove the part from the oven the next morning.
   • If you used a blowtorch to loosen steel, place the piece on an anvil or other massive steel object to dissipate heat.

Warnings

• Wear safety goggles and gloves when working with hot metal.
• Do not touch metal with bare hands, as this can cause severe burns.
• Keep a fire extinguisher near your work area in case of fire.

What do you need

• Blowtorch
• Pyro
• Steel detail
• Metal tongs
• Protective glasses
• Work gloves
• Heat resistant container
• Vegetable oil or water
• Rags
• Oven