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Powder coating: galvanneal vs. straight cold rolled


We make racks and cabinets that are used in data centers. For durability, our parts are powder coated, and we use A60 galvanneal for additional corrosion prevention. We've been told by suppliers that this is overkill, but we switched from cold rolled to galvanneal a few years back because of issues with parts developing rust prior to powder coating.

We are now trying to source our products globally, and we're finding that our international suppliers cannot easily obtain galvanneal. My instinct says that we'd be safe to use straight cold rolled steel (as most of our competitors do), but I'm hoping that someone more experience that I can advise on the following:
1) What additional controls might we need to implement in our in-house pretreatment and powder coating?
2) How to specify corrosion performance requirements to outside (and remote) suppliers?
3) How much additional risk are we taking on as a result of going away from galvanneal?

Max Hibner
Data center infastructure products - Project engineer - Chicago, Illinois, USA


Question number 1: For anyone to respond you will have to include what your current process, e.i. # stage dip or conveyorized system, type of chemicals etc,etc.
2. This is normally specified as a salt spray result. Your supplier will tell you "we can produce 700hrs salt spray". The higher the salt spray number the better the system(supposedly).If they ask you what salt spray means, don't even consider them. What you need to make clear before you accept them as a supplier is that they are testing the substrate that they will be providing you, being processed through their existing system. Some suppliers like to use trick QA panels that bump up the test results.
3. The first shipment of product returned to you(or field repair) that has the paint falling off, sounds like you might have experience with this.
It seems to me that your instincts should be telling you to stay with galvanneal.

Sheldon Taylor
Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina

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