This lowers the chance of cracking the blade. Gases are released in the quench and would form a "trap" around the steel unless you keep them moving for a minute or so. Same wrap – Harden at 1900F degrees and only about 15 minutes at temperature – then plate quench and cryo as above. Q7:  Aluminum is expensive! Make sure all the oil is cleaned from the blade or your house will smell like oily smoke and your knife making career may be cut short by the boss of the kitchen. To test that a blade is ready to quench a magnet may be used. Soak in solution. 1095 Bar stock from the mill probably shouldn’t have to be Normalized, especially if it has been annealed. All of our stainless blades get double wrapped in high temperature, 309SS foil envelopes – with double folded seams pressed down firmly. If you drop it now, it will shatter. I have a left a piece of steel overnight untempered and found it cracked the next day from the stress hardening puts into the steel. 125°F). The risk is that the 321 will either fail, allowing air in, or stick to the blade inside. Handle your blade carefully at this stage or you may end up with a cracked or broken blade. We test every blade through here and write the hardness on the blade before shipping it out. This step should be carried out soon after heat treating, within an hour or so, but only after the blade has cooled to room temperature. Bar stock from the mill probably shouldn’t have to be Normalized, especially if it has been annealed. They don’t have to go straight into cryo, but aim for something less than an hour from plate quenching. While blades are cooling allow the furnace to cool down to 950°F. 2 pieces for an average hunter and four for a big bowie. Knife and Blade Heat Treating Furnace We bought this KM18T Pro 3 Zone Paragon heat treating furnace to replace the older Paragon heat treating furnaces we were using for stainless steel.