Steel quench tank, protect from surface rust ?

[Capntom]

We have a 300 Gallon steel tank. The tank is used for water quenching of heat treated parts. The parts are about 400°F going into the tank. The quenching media is 5% Glycol mixed with water. Temp of the water never gets over 100° F. We, as expected, are experiencing surface rust after we sand the inside shiny. Would attaching submerged Zinc anodes to the inside of the tank reduce or eliminate this mild rust. The quenched parts are Aircraft Aluminum and iron oxide staining is not good.

 

[whammett]

It depends, more than likely, yes. Post the exact specs for the metals you are using. What is the spec on the steel for the tank? And then the parts?

The anodes should work for cathodic protection, but I can't deduct much information from a galvanic scale chart without you providing precise specs.

"Scientists dream about doing great things. Engineers do them." -James Michener

 

[redpicker]

Contact the manufacturer of your quenchant. They should be able to advise you on what steps are needed to address this problem.

rp

 

[CoryPad]

I agree with rp. I don't think you want to add a lot of Zn ions into your solution. A better choice is to add a rust preventive additive in the quenchant.