<snip>
< food grade stainless) allowed legislators to justify keeping
< a strong hold on the tax revenues for hard liquors.
what is food grade steel? just curious.
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I'm no expert. I was simply cautioned to specify food grade
stainless and contruction methods when buying some long term
storage containers, so I did and wasn't questioned about it
when I ordered them. I had done a little reading before,
though, and the following summarizes what I'd gathered up.
There are certain types of stainless alloys and annealing
used for food handling and containers. I gather what is used
depends upon the use and the construction. I've read about
types 302, 303, 304, 316, 420, and 430. (303 doesn't weld
well, but machines okay, for example. So an application which
requires welding wouldn't use it.) I think there is more than
just "type" involved. For example, there are 304L and 316L
types used for food. You may also have to watch out for
additives, like sulfur, used to improve machining. Type
number alone may not tell you all you need to know.
From "The Making and Shaping of Steel" from United States
Sttel: Type 302, austenitic 18-8 with 0.15% max carbon, 8% to
10% nickel, and 17% to 19% chromium is corrosion resistant
and has good ductility and may be deep drawn and formed. It
may also be welded if the heat zones are cooled rapidly.
(Otherwise intergrannular corrosion may happen in the welds.
But that can be corrected by annealing above 1900F, followed
by rapid cooling to trap the carbides in situ.)
It's also not only a type of steel but also how you handle
the design and finishing methods to sufficiently reduce pits
or anything else that may promote bacterial growth and also
to provide surfaces that can be reliably (repeatably) cleaned
and sanitized. You know, the welds need to be smooth for
example and not deeply pitted, for example.
But you can't ignore the type of steel. The selection is
limited by the food it will contain, duration, environment,
and the methods of cleaning and reuse.
I wish I knew more about the subject, but I'm a consumer not
a designer of these products.
Jon