Fog Quenching

My plan was to start with water spray only. I have a dozen or so water spray nozzles with an output of 5GPH @ 100psi. My thought is to run it at 100psi and then through an adjustable flow meter that’s graduated in GPH I have another one that CC/min. I would space them eavenly out in a row down opposite sides of an aluminum pipe. There would be a catch container below. The water would be supplied from a tank that’s pressurized. My thought is that measuring actual flow of water to all the jets will give me an accurate way to tell water volume per jet. The jets have a spray angle of 80° So I will be able to have good And even spread.

Now for testing quench speed you could do a comparison test using oil and data logging the drop. I thought I read somewhere that thy use a 1” diameter nickle ball. I could embed a TC into somthing and data log the speed of my parks 50 vs the spray.

my thought is if you had the spray valved you could insert the blade between the nozzles and trigger the spray and the entire blade would get evenly cooled. Hell you could have it connected to a pid or arduino and program on off times or pulse lengths. Now my brain is running away so I better stop.
 
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JT, that book Natlek quoted from had a lot of great info. I got a copy from my county library. It's called "Heat Treatment:Theory, Techniques and Applications" by Bonami, Gregory J.
They've got graphs comparing cooling rate to oil and water quench. In particular, they tested nozzle design, water and air pressures. One key takeaway is that smaller droplets have more surface area to volume, but lack the momentum to break through the vapor. The goal is to hammer through that, as you mentioned, to try to maintain nucleate-transition boiling. Obviously you can record water flow, but the the correlation of that somewhat depends on your overspray. They have a way of checking cooling rate - embedding a thermocouple in a block and logging temp during quenches.

One more crazy thing to consider: some industrial plate quench lines use spray nozzles in a "quench press" which really is just doubled up pinch rollers with spray in between. You obviously wouldn't want that sort of design, but I wonder about a fog-spraying clamping head for your pneumatic plate quenching machine (to prevent distortion). I would picture some sort of waffled face.
 
I would probably start with small coupons and only 2 nozzles to simplify things. Yeah velocity is king from what I gleaned from reading.
 
JTknives JTknives I don't know it you saw the discussion on oil or not, but Maxim seems to have the best prices going on #50 quench oil. Which I understand to be Parks 50
 
Fallbrook Forge said:
JTknives JTknives I don't know it you saw the discussion on oil or not, but Maxim seems to have the best prices going on #50 quench oil. Which I understand to be Parks 50
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Yeah that’s where I have gotten my oil in the past. I think thy have been the only place to get it for awhile. I know a few other places that sell smaller quantities of it at a marked up price.
 
Another idea is that you use polymer water-based quenchant. The pros are:
  1. Safety - no risk of fire.
  2. Economical to purchase - it is sold as a concentrate, you add water.
  3. Adjustable quench rate.
  4. No concern of water contamination, which means cooling the quenchant is much more straightforward than oil. You could put ice in it.
  5. Easy to cool with standard auto radiator parts (it has similar viscosity to antifreeze).
As for measuring the quench speed, the nickel ball is the old-school method. The newer way is to immerse a heating element (think a piece of kanthal) and slowly increase amperage until the element burns out. The max amps before burn-out is a numerical representation of your quenching speed. You'd have to look up the math to understand how to arrive at a meaningful numerical value.
 
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