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Heat Treatment

What happens to steel depends not only on how hot it is, but on how it got there.

Hardening (quenching)

Take a Steel Ingot out of the crucible while it's still very hot and throw it into water. If it's at 1400 Tu or more when it lands, it becomes Hardened Steel. You'll hear the hiss.

  • The ingot cools at 30 Tu a second from the moment it leaves the crucible. Steel's band tops out at 1410, so pulled from the middle of the band it's already too cool. Heat the finished ingot higher first (it's done; the spoil line no longer applies to it), and have water right next to the crucible: from 1460 Tu you have two seconds.
  • Any water works: a pool, a river, a single water block.
  • A steel ingot that's too cool just gets cooled. Nothing is lost except the heat, so reheat and try again.

Hardened steel is extremely hard, too hard for the Drill Press or Lathe. Only the Grinding Wheel can shape it.

Tempering

Hardened steel is hard but brittle. Tempering it gives Tempered Steel. JEI's figures:
Band 300–400 Tu
Fastest at 350 Tu
Hold 20 seconds, at 350
Special rule only counts while it's cooling

The catch is that last line. Holding hardened steel steady at 350 does nothing. It only makes progress while the temperature is falling through the band. If it's flat or rising, progress just pauses (you don't lose any).

So the method is:

  1. Heat it a bit past the top of the band.
  2. Cut the heat and let it cool down through the band.
  3. If it drops out of the bottom before it's done, heat it up again and repeat.

Ways to do it:

  • Annealing Furnace: it physically can't get hotter than the band, so you can't overcook it, and it's heavy enough to cool slowly. Fuel it, let it top out, let the fuel run down. It's the safe, simple way.
  • Crucible with Dampers: heat past the band, then open the dampers to cool on cue. It's faster and more controllable, but you can overshoot. A Controller can run the dampers for you.
  • Heat Exchanger cooling counts too.