Heated Steel Question

[ToughOldFord]

What are the pro and/or cons of dipping something you just welded or torched in water or hosing off a heated project?
Steel is the subject on my mind, but any info is good.

[averagef250]

It all depends on the alloy, but even mild steel will get a bit brittle in the HAZ from a fast quench.

[ToughOldFord]

Thanks Dustin, sounds like a good general rule then would be to let it cool down naturally.

[averagef250]

Slow cool is usually a good idea. If you need it cooled down faster air is a better way to cool without shocking the metal. Blast with an air nozzle or just a fan blowing on it will speed up cooling without harming stuff.

That said, if you're welding a coathanger or a wheelbarrow and it doesn't matter if the weld is strong then cool it off, but if you're welding a truck frame or an excavator boom it's not only a good idea to let it cool slowly, but to insulate the area and also needle scale the area to relieve stress.