Author Topic: Aluminized Steel Plate  (Read 6154 times)

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Offline Meatballs

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Re: Aluminized Steel Plate
« Reply #25 on: January 12, 2013, 05:42:57 PM »
Craig, THANK YOU!

My area of expertise lies outside the fields of thermodynamics and metallurgy.  But, I knew somebody here would have the smarts.  I can give measurements, I can photograph pizzas, most of all though, I know when a pizza is good.  I've been getting some really good pizzas off of this plate for some time but it wasn't until I tried it in a regular, moderate quality, electric oven that I realized something was going on.  I mean, I launched a pizza off a cardboard peel cut from a pizza box at a beach house and produced something better than you can get for 50 miles around in a cheap oven (I did use my skills, broiler after preheat, etc.)

I can tell that there is something going on with the metallurgy and design of the plate but I can't tell you exactly what.  My home gas oven is powerful, its marked to 500 but the knob keeps turning to an guestimated 600.  I've taken it to 520 - 550 but hesitate to go further because the plate has a nonstick coating.  The nonstick is, by the way, flat black.  I feel it may have some impact in infrared absorption but, again, outside my field of expertise.  I read the information you posted, but, its mostly Greek to me, I really would appreciate your take on the information in simpler terms without the Lambas and T1's and all.

Scott, as to cutting the plate, well...no.  But, I am considering buying a full size plate and cutting it down to fit my gas oven so I can launch 14 to 16 inch pies.  A scrap off of that would be useful for comparisons.  Amazon shows a CAP-F (full size plate) at an external website for $45.00 with shipping that fits my retired budget.  As to the steel plate... there us a steel fabrication industry here that probable could probably supply such, what type of steel and how much does it cost, because it will probably end up down on my shooting range as a target.  How big a piece would I need to get the numbers if I lined it up with a piece of scrap from the full size plate?  I suppose I could bake a small pizza over both pieces of material.

Ron



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Re: Aluminized Steel Plate
« Reply #26 on: January 12, 2013, 11:17:02 PM »
Prior to hearing this, I would have bet just about any amount of money that aluminized steel had the same thermal conductivity as regular steel.  

So would I, and after further thought, I don't think I believe the thermal conductivity number in the AK Steel product data sheet.

Here is why I say that - we can think of the problem in terms of conductive heat transfer:

Fourier's Law of Heat Conduction:  q = k A (ΔT/s)       [1]

q =heat transfer (W)
k = thermal conductivity of the material (W/mK)
A = heat transfer area (m2)
ΔT = temperature difference across the material (K)
s = material thickness (m)

This formula can be extended to calculate heat transfer across multiple materials in series:

q = (ΔT) / ((s1/(k1A)) + (s2/(k2A)) + ... + (sn/(knA)))     [2]

We can use these thermal conductivity values:

Low carbon steel = 64 W/mK
Aluminum = 205 W/mK

And these thicknesses provided by AK Steel (the extremes that should give the highest k):

Low carbon steel = 0.15in (0.000381m) the thinnest they offer
Aluminum = 1.2mil (0.00003048m) the thickest they offer

Were calculating a constant k for the clad metal, so it doesnt matter what you use for A or ΔT and long as you use the same values throughout the steps (see [4] below).

Insert the values into [2] and solve for q (remember there are two layers of Al same thing in [3] when you figure s for the Al-steel-Al clad).

Rearrange [1] to solve for k = (qs)/(AΔT)       [3]

Insert q from [1] and the other values into [3] and solve for k = 70.7 W/mK which is a lot lower than 89 W/mK. I just dont see how you can get to 89 with any reasonable set of assumptions. It almost looks like they did a weighted average k which would not be correct.

Inserting [2] into [3] and simplifying yields

kclad = (s1 + s2 + + sn) / ((s1/k1) + (s2/k2) + + (sn/kn))     [4]

which can be used to calculate the thermal conductivity for any n-layered clad material.

Back to the question at hand, if you use a steel thickness of 0.2in, and aluminum thickness of 1.2mil, the increase in thermal conductivity over plain steel is about 0.5 W/mK which is completely insignificant. The thicker the steel, the less the increase.

I guess this brings back to where we started. Sorry Ron. :(

CL

Pizza is not bread. Craig's Neapolitan Garage

Offline tinroofrusted

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Re: Aluminized Steel Plate
« Reply #27 on: February 08, 2013, 11:37:36 AM »
Thanks to Meatballs and everyone else for their comments on the aluminized steel plate.  I have held off on buying a carbon steel plate just because they are so heavy and I didn't want to deal with all that weight.  I went ahead and ordered the Cadco CAP-H, 20" x 13 1/2" Non-Stick Aluminized Steel Pizza Heat Plate. The cost was $34.00 with free delivery.  It's a perfect size for my oven, (an Electrolux with convection). I think I will try it out sitting on top of a couple of really well heated pizza stones and see how that goes.  I will report in to let you know how it goes. 

Offline usemobile

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Re: Aluminized Steel Plate
« Reply #28 on: October 30, 2013, 06:43:50 AM »
Preheat is great, but recovery is another story. If you need to wait 15-20 minutes between pizza's then that becomes an issue.

That's an experiment I'd like to see done.

i want to try on Copper pan for pizza baking, Any experience on this ...like making pizza on copper pan offcourse copper is expensive metal for pans. But i would like to try on it


Offline bbqchuck

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Re: Aluminized Steel Plate
« Reply #29 on: October 30, 2013, 08:27:09 AM »
Copper has a huge conductivity value compared to steel.  But like you mentioned,  its price is also huge.  I backed off the idea of an experiment just due to the cost and unknown results.   Sometimes more is not necessarily better.  But aluminum is certainly cheap enough.  You might look at a 3/4"-1" aluminum plate. 

I tried my 1/4" steel plate on my Blackstone oven and got a more leathery crust.  But when you put in the variable of the oven temperature extremes, like the Blackstone can produce,   experiments start getting out of hand just due to the volume of datapoints to see what happens across large temperature ranges.   For example,  the typical home oven user of a steel plate is running them at around 500-550f.  The Blackstone can run from that temperature to easily 900f.  So how many datapoints do you want?  Throw in time variables and the results get fuzzy-er to make sense of.   

So possibly you can recreate the results of a Blackstone oven with the deck stone at 800f and the burner at 70% by using some metal heated within the range capability of a home oven and up against the broiler fooled into running all the time.  I dunno.  But i just thought it was easier to get massively more heat by getting a blackstone.  So far i think the blackstone is much easier to change results than a home oven with stones, metal plates, screens, etc..

Online TXCraig1

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Re: Aluminized Steel Plate
« Reply #30 on: October 30, 2013, 08:46:53 AM »
i want to try on Copper pan for pizza baking, Any experience on this ...like making pizza on copper pan offcourse copper is expensive metal for pans. But i would like to try on it

A copper pan simply will not hold enough heat to be of any use.
Pizza is not bread. Craig's Neapolitan Garage