quench tank for ss and alloys

[joecontrol]

Gents,

I am in the process of putting a heattreat facility together for stainless and alloy steels. It will be a l x w x h--- 30'x6'x 5'
It looks like the level will be around 48"Dp to allow for displacement.
I am thinking of using the same size tank as a cold tank recirculating the fluid from the cold tank to the cooling tower & quench tank.
I am thinking a 7 - 10 hp pump 300 gpm to change quench tank volume in a 1/2 hour.Is this fast enough??

My question is if i dip 8,000 lbs of 1900 deg f steel into a tank of fluid(water)or (oil) at 90 deg f how much temp rise should i expect.
I need to keep it below 115 deg f.
I need to size one cooling tower for water and one for oil and i don't want to oversize them.

Thanks to everyone for your time,Joe

 

[metengr]

My question is if i dip 8,000 lbs of 1900 deg f steel into a tank of fluid(water)or (oil) at 90 deg f how much temp rise should i expect.
I need to keep it below 115 deg f.

Joe;
There are two parts to evaluating your quench tank; part 1 is to determine the heat capacity of the hot steel. The second part assumes that the heat given off by the hot steel will heat up the water or oil in the quench tank. The heat capacity for the hot steel and the fluid that will absorb the heat can be calculated using the heat capacity formula below;

Q= m*C_p * T_i - T_f

where Q= heat
m= mass of material or fluid

T_i = Temperature initial
T_f = Temperature final

Knowing the mass of steel, the initial temperature at 1900 deg F and the final temperature at 115 deg F, and the heat capacity for steel, plug in the values and solve for Q. Whatch your units.

Now, the basic assumption is that the heat given off by the hot steel during cooling is going to be used to heat the fluid from ambient temperature to 115 deg F (your limit). Knowing the heat capacity of the fluid (water or oil), solve for the mass of the quench fluid in the equation above needed to achieve the heat transfer.

If you have fixed your volume or mass of fluid, you can also calculate the final temperature of the fluid after cooling the hot steel to ambient temperature. In this case, you know the volume or mass of fluid, Q and the initial temperature (ambient). Solve for T final.

Regarding cooling and volume of fluid turnover, this becomes a more complicated thermodynamics problem of dissipating heat in a fluid using a heat exchanger. I believe you can look up one of the formulas used for a heat exchanger design, where the fluid temperature in/out, velocity and the gas side temperature in/out determines the surface area needed for the heat exchanger.

Advice;
If you are not an engineer, hire out the necessary expertise to an engineering company that can properly size the quench tank and determine external cooling requirements.

 

[EdStainless]

Why liquid quench? Unless these are thick section parts forced air cooling should be fine. Are you going to do a lot of high carbon grades?

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[joecontrol]

Thanks for the quick responses,

We will also be building an air quench bench for these parts. The bars will be from 2" to 6" in cross section mostly rounds.We also have the possiblity of 3" x 6" x 12.5' flats.

The big problem is we are still in the proposal phase and i would like to reduce the inital cost to a resonable amount before hiring a firm to do all the detail eng.
Thanks to Meteng for the formula i can at lest figure out some items.

We are going to be doing many different grades of stainless and alloy steels and the customer wants to have the oil quench if his customer demands it.

Thanks for the info,Joe

 

[kenvlach]

Joe,
I agree with metengr re getting some professional advice. Cooling during quenching is too complex to solve analytically -- parts get surrounded by a vapor blanket, fluid viscosity changes, there are fast, medium & slow oils, water-soluble oils, all sorts of additives, agitation flow, etc.

Try to get some free professional advice from suppliers such as
Heatbath

http://www.heatbath.com/

and Houghton

http://www.houghtonintl.com/

I strongly suggest reading the first 70 pages on quenching in chapter 13 of Physical Metallurgy Handbook (2003)

http://www.campusi.com/bookFind/asp/bookFindPriceLst.asp?prodId=0070579865

 

[joecontrol]

Thanks,kenvlach

I will read the chapter for sure!! Yes i do understand the issuse with vaporazation somewhat. I currently have my customers metallergist telling me the quenchants they are going to be using i.e. oil and water quenchant mixture.

Then I am going to try the vendor and see how much help i can get.Houghton looks like they would be helpfull.

Is there any other books i should get for ref.

I thik it is best to try and understand what the customer is trying to do. I am the instrumentation guy and i usually get stuck figuring out how to make it happen.I situation such as this we will hire someone to do the details and let me know what the process is so we can make it happen.

Thanks for your time,Joe

 

[TVP]

Joe,

Definitely call Houghton. Ask to speak to Scott MacKenzie. He is one of the world's foremost experts on quenching, and should be able to help you with your design.

 

[joecontrol]

Thanks,for all the good info.

In speaking with others and gathering info i have found a few "rules of thumb" and they will work so i can work up a budget proposal for the diffent quench tanks and cooling equipment i will need.

This is something that many stainless and alloy producers have done for years so after diggin around i found some good old books from Beth steel and al teledyne and some others that has helped.

I appreciate all the tips and book suggestions and i will get that book.to use in the future.

i am still a greenhorn in the furnace and heatreat bis i been doing this for 12 yrs now but i got to do it for 20 to 25 more.

Thanks,Joe

The next thing is stiff leg crane design.
Know any good guys??

 

[JoePa]

Joe,

I have a large quench tank with agitation manufactured by GM Enterprises for sale. I have some pictures of it and I'll have the specs on it tomorrow. It was only used for R&D and has virtually no runtime -- originally purchased for $50K. Please let me know if you or anyone else would be interested.

Best regards,

Joe Massaro

SEI
Shroyer Electric, Inc.
Equipment Sales
Office - (814) 479-4346 Ext. 1
Fax – (814) 479-2196
Cell - (814) 327-9810
Email – JoeMassaro@aol.com