Plate Quenching Air Hardening Steels

I strongly suspect that Mete is correct. I have never seen any steel heatsinks used in my 20+ years working in the electronics industry. They are almost always Al. The exception are some high-performance, cost-no-object applications that use Cu.

Phil
 
pso said:
I strongly suspect that Mete is correct. I have never seen any steel heatsinks used in my 20+ years working in the electronics industry. They are almost always Al. The exception are some high-performance, cost-no-object applications that use Cu.

Phil
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Not the same thing. Your heat sinks were trying to achieve maximum heat transfer to keep something as cool as possible. The plates used for plate quench don't need maximum heat transfer, they need to cool quickly enough to get under the TTT nose for the steel, which for an air quench steel is easily achieved.

Heat conductivity of aluminum compared to steel is 3X
Heat conductivity of aluminum compared to air is ORDERS OF MAGNITUDE

This is air quench steel we're talking about...

BTW, this is a way over simplification of a heat transfer equation which includes delta T (which will be different for steel than aluminum during quench), specific heat, heat conductivity and heat loss through radiation, not just conduction.

I'm pretty sure this is an area where it either works or it doesn't work, not a situation where if fast is good, faster is better. At least as far as such a small difference is concerned.

I have 2" aluminum plate in my shop, but I plate quench with long bars of 1018 cold rolled steel because the shape is more convenient for me.

I'm not suggesting that steel is better than aluminum. But someone above stated that big plates of aluminum are expensive, so I'm pointing out that steel (which is cheaper and more durable) is probably a good alternative.

Steel has twice the thermal mass too (specific heat), so it doesn't get as hot as aluminum during a quench.

I'm not disagreeing with Mete. Mete didn't say steel doesn't work. He pointed out that aluminum is three times a better heat conductor. He said that, as far as steel is concerned, you'd have to experiment. I have.

Just my .02
 
When i use air hardening steels i have the use of the local machine shop h.t.oven and i pull the knives from the foil, some dont but i do(because i tried quenching one in the wrap and when i took it out it had a beautifull crook in the blade right where the tip was on the folded edge of the envolope) and lay the knife on a big chunk of steel put another big chunk on top and leave it till cool. It works for me just fine.
 
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