How to Heat Treat C120 Steel

Hardening

• 1

  In a safe, low fire hazard workspace, fill a pan or bucket with peanut oil. You can substitute other oils, but use an oil with a low flash point, as there is some danger of the oil surface igniting, especially if the oil has flammable additives.

• 2

  Place a magnet in a bench vice very near your work station. You'll use this magnet to test the steel's temperature.

• 3

  Heat your C120 steel with an oxyacetylene torch, holding it with a pair of tongs. The heat transfers a long way, so wear welder gloves, as your tongs may get hot.

• 4

  As the steel changes color, it nears the curie point -- the point at which it ceases to respond to magnetism. Tap the heated steel against the magnet as the temperature temperature rises and color changes.

• 5

  Continue heating the steel until it reaches the curie point and is no longer attracted to the magnet, or has lost most of its magnetic response.

• 6

  Dunk the heated steel into the oil bath and let it cool. It takes only a second to harden. Let it cool a bit longer, and give it many minutes to cool before you handle it.

Tempering

• 7

  Preheat your oven, or a oil in a deep fat fryer to 350 degrees Fahrenheit.

• 8

  Place the still in the oven or fryer and allow it 10 minutes or so to heat.

• 9

  Remove the steel and set it in a safe place tool cool at air temperature.

Annealing

• 10

  Heat the steel to the curie point, but don't quench it.

• 11

  Place it into an insulator that controls the timing of it's cooling, allowing it to cool gradually. You can use wood coals, charcoals, an oven or superheated sand, in which you can submerse the steel.