When hardening blades, especially large ones, warpage can sometimes occur. The choice of steel can minimise the risk, as can a good normalising cycle, but sometimes it just happens.There are a number of different ways to try and fix the bend, not all of them are guarenteed.
One gentle way is to use a Japanese straightening stick or "Magebo". I found this in Murray Carter's excellent book "Bladesmithing with Murray Carter". It is made with a large piece of hardwood, by cutting a slot or to (just thicker than the blade thickness) and making a handle. The bent blade is first tempered, then the back softened. This is to reduce the risk of breaking. The blade is then placed in the slot, where the bend is, and some gentle pressure applied to torque it straight. Gently does it.
It possiby could be used straight after quenching when still hot, I'll have to try it. I dont normally expect my blades to warp, but should have the Magebo hanging up near when I heat treat for emergencies.
