Is it common to order dual certified stainless steel fittings and pipe (304/304L) to benefit of the properties of both materials? Or is there a higher probability that such pipe/fittings can't be delivered?
In my region it's tough to find fittings, pipe etc. in 304 or 316 that are NOT dual certified any more. Everybody's been stocking dual grade materials as the standard for at least the past 5+ years. Bar and plate are a different story, so product form matters a bit.
Dual certified materials meet the key requirements of both specs. 304/304L dual certified material has the strength to permit you to use the higher stress values for 304 material, while also meeting the low carbon spec of 304L grade for weldability.