How to prevent warping?

Z

Zanuha

Joined
Sep 27, 2010
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437
Ohai. I've been making a small persian-style neck knife, and I need to HT it tomorrow. It can't go wrong, it's the last day of school and too damn muddy at my shop to quench it there. Anyway, I'll be using a gas forge and canola oil. I've been thinking about screwing plates of iron or mild steel onto the handle. Is there anything else I could do to prevent or fix warping? The handle scales are already done and too tiny to reuse, so warping the blade now would be a hell of a bummer.
 
Heat it evenly and allow to soak at the target temperature - 815°C/1500°F - for about five minutes.
Warm the canola oil to 55°C/130°F before the quench.
Quench straight in, point first, and move the blade only up and down, not side to side.
Count to ten while quenching, and after the ten seconds, pull out the blade and examine it. You have a short window ( about 30 seconds) to straighten the blade in a vise or on the anvil. Until the blade drops below 200°C/400°F, it will be very soft and easily straightened. You can used gloved hands for small warps/bends. For more stubborn warps and such, use a wooden mallet and a piece of board on the anvil face to avoid making any marks or dents in the blade. If the blade starts to feel "stiff", stop any straightening attempts, as it will break once it drops below the martensitic start point.Once the blade is straight, place back in the oil and leave to cool for several minutes. Wash off and temper as soon as possible.
Any remaining twists or bends can be straightened after the first temper while still at the tempering heat ,which should be around 220°C/425°F for 1084.
 
Last edited:
Alright, it didn't warp. :D
The forge was out of gas so I had to use a simple gas burner to heat the blade up. The heat was pretty uneven, so we'll just have to see how it turned out.
 
I agree with Stacy's post other than two points. The OP said he was using his gas forge so nailing those temps/soaks isn't feasable and when straightening during an interupted quench, I would avoid all heavt steel tooling (anvils, vices) unless they are preheated. I can just imagine the heat that an anvil would suck out of a thin blade. Plus using heavy gloves could also give you an idea of where the temperature is.
 
I suggested a wooden board placed ON the anvil and a wooden mallet to do the hammering.
 
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