Hey JMR,
I take it since you say 400 degrees you were tempering the blade. If that's so, the bend in the blade isn't the only problem ya got. Temper only occurs when the blade is allowed to cool slowly. If it was cooled fast enough to bend, the temper is messed up as well.
If you use Ray's method or any other mechanical method, you can reduce the risk of the blade snapping by heating it back up to 400 as well. I've actually put um on a board with the bend up, laid a piece of 2x2 on it and whacked it with a hammer. Works for minor bends. Then re-temper it.
This time use a dish of sand heated to 400. Set the blade in edge down for 2 hours and let the whole thing cool to room temp inside the oven. Should eliminate any chance of warping.