Most manufacturers of stainless steel pipe pickle and passivate after the pipe is manufactured. Some manufacturers "bright anneal" small (ie 4 or 6" and smaller) and do not p&p it. However, almost all welded ss pipe is p&p after the manufacturing process.
At 14", stainless wall thicknesses change from Sch40s to Standard wall, the same as standard wall carbon steel.
14" pipe is available in standard wall from Bristol Metals in Bristol, Tennessee.