Stainless Steel Flat Bar comes in various alloys of which the most common are 303, 304 and 316. It is produced in all sizes and finishes.
One of the most common differences in the way most other metal flat bars and Stainless Steel Flat Bar are produced is that sheared plate is often "edge treated" and sold as flat bar and "True" Flat Bar. which is produced to size.
HRAP (Hot Rolled, Annealed and Pickled) is produced at the mill to the specific size indicated. The finish on all four sides is virtually identical. The corners are relatively square, and the tolerances are reasonably close to the actual dimension listed – usually within just a few thousandths of an inch. Also known as "True Flat Bar".
SHEARED AND EDGED is bar cut and processed from stainless plate. The edges are milled and have a slightly different finish from the flat sides. Though it is flattened and straightened as part of the process, sheared and edged bar is not as dimensional “true” as true flat bar. Still, it remains an extremely viable and much less expensive alternative to true flat bar.
Finishes: There are a couple of standard finishes available today, HRAP and Cold Finished (aka Cold Drawn).
HRAP: Hot Rolled, Annealed, and Pickled (aka "MILL" Finish) has a dull gray, rough finish that comes as it was produced and it mostly dimensional larger than listed sizes.
COLD FINISHED: A shinier finish, with sharp edges and dimensional closer to listed size. This finish is most commonly produced in the 303 alloy.