First kitchen knife, experimenting with the quench

[Hammarfest]

I mainly make fighting blades, usually with 5160 which I have an abundant supply of, and this is my first attempt at a kitchen knife.
Someone recently destroyed my lawn mower, may it rest in peace, and I harvested the blade. A friend asked for me to forge him a chef's knife, which after flattening the mower blade in the forge, it was fairly easy to get the shape I was looking for. This is total experimentation, so I can learn and use the proper steel in the future for any other kitchen knifes.

My question now is what to quench in. I'm used to quenching the 5160 blades in vegetable oil, which works wonderfully. #1 I'm not sure of the steel in this mower blade, it seems to be fairly high carbon after the spark test. #2 With this being a chef's knife, it is much thinner than my normal blades and I assume a higher hardness is desirable in a kitchen knife, which makes me wondering if water or brine quenching may be the way to go.

If this piece goes the way of the dodo, I won't cry, so I am open to experimenting and learning.

To quench in oil, water or brine is the question, advice very much welcome!

 

[weo]

If you want to be safe, try oil (the slowest of your options) first. If it doesn't harden, then try water, if it still doesn't harden, then try brine (the fastest of the 3 you mentioned). Too fast of a quench will crack the blade during the quench, so it's safer to start too slow.
Or, even better, take another piece (or 3) of said lawnmower blade, and do the experiment with these coupons to see what is the best quench medium for this unknown steel.

 

[Nick-D]

Sounds like the perfect time to invest in some proper quench oil. You will get better results with your fighting knives and the best chance of a good result with your mystery steel

 

[A.McPherson]

Agreed! Some parks 50 oil will serve you well, and it's  almost as fast as water. But way gentler.