....I'm getting unacceptable scaling, but with small patches of nice color....
....I heard a "pop", and when I opened the kiln there were flames coming out of the crucible along the edge seam of the lid....
I think, if you get patches of color and some true scale forming, then maybe some of the steel was protected from oxygen (formed colors), and some of the steel was exposed to oxygen (scale) when it was in the higher temp. range. I would guess that your crucible made it through the heat cycle, and maybe O2 is reaching the parts during your quench.
Just the flames that you saw may not mean anything by themselves. If the material was up to temp and air got in if the cover moved, chances are it would show a flare up.
I would think the main reason to use known materials would be to minimize the chance of surprises. If you have the Venters, Gun Craft, book, R. Brown makes mention of how they cook their materials to burn off possible impurities. He also thinks if the technique is sound, that flaking is oils either from inadequate cleaning or residual in the charcoal.
Only thoughts Ken, best of luck with it.
