Well, like any steel you can certainly quench too fast. Faster quench rates will generally result in a little lower retained austenite, but a much higher risk of cracks. Plate quenching between aluminum plates is the way to go. Knowing that there was no cryo, I’m going to guess that you have high retained austenite in the blade. The spring may have cooled at a faster rate, resulting in lower RA. If you don’t have a means to cryo, you can try to use the higher tempering temperatures as these will generally help convert the remaining RA. Chances are though, if it’s been some time since you heat treated it, the RA has stabilized and will not convert to martensite well. If that is the problem, all you can do is redo the heat treat at this point. I wouldn’t recommend finishing the blade in its current state. It will be more prone to breaking, and won’t really hold up well for cutting. 154 is a little tricky to heat treat, but it is an excellent steel when done properly.
