enamel coating on carbon steel container

[offonoff]

There are enamel cooking pots, water heaters and iron bathtubs. I'm wondering if anyone knows about enameling a carbon steel vessel that will be used in a "food grade" operation. (stainless is just too expensive)

The temperature will not be much, that of boiling water at most, so the enamel for cookware should be adequate, but I cannot find a source of this paint or powder.

Am also wondering if anyone knows of any pressure limitations on an enameled vessel. I think I read that the boilers in nuclear power plants are enameled, and that glass performs well under compressional loads but i've no more information than that.

 

[btrueblood]

Porcelain enamel is a glass-like coating, used on cookware, that is applied (typically) as a wet coat, dried, then fired at high temperature to fuse (melt) the porcelain into a glossy, tightly adhered coating.

Enamel paint comes in spray cans. It would burn away rapidly if exposed to the burners on a kitchen stove.

Somewhere between those two are coatings like Xylan (Whitford coatings) that are a teflon or nylon based coating, fired at medium temperatures (a few hundred deg. F) to cure the polymer.

Depending on what you want, googling the above terms (the ones in italics) should help you find it...

 

[TVP]

offonoff,

What stainless steel grades have you evaluated? Any duplex alloys like LDX2101? They can be made thinner due to higher strength and have similar or better corrosion resistance to Type 304. 2xx series stainless steels are another potential low cost option.

 

[offonoff]

define low cost.

I've looked only at 304 stainless flanges and fittings. I was quoted 10 times the price of an a105 carbon fitting for a 304 stainless one.

Carbon steel is abundant and local machinists have it on hand in large diameters. even if these uncommon alloys were attainable in large diameter, short length tubes (for fabrication of our vessel), and were 1/4 the price of 304 stainless, that's still 2.5 times the price of a105 carbon steel.

That said, I might look into alternatives to 304 stainless for the external piping. How would i find 1/4" pipe and fittings in these alloys?

Also, I will suggest the possibility of different alloys to our machinists and see what they know about using it in our project.

thanks