Looking in a HT oven will not give you a good color judgement. The TC and readout is the best indicator. If that is in doubt, use some sort of test cone or other indicator like a Tempil stick to see how close the oven temp is to the readout.
I would almost guarantee they are hard and you have not ground away the decarb. Even if the oven went to 1900F, they would have hardened fully upon quench. The grain may be huge, and they may warp ... but they would harden. Be sure to temper them before doing anything more, as they are probably brittle. If you truly think they got to 1900F, normalize them and refine the grain, then re-do the HT.
All blades HTed in an open forge or oven will have a soft layer of decarb that needs to be ground off. A few seconds on the belt and suddenly you are throwing sparks and find the hard metal.
