Get an inside view of ASTM A403 WP321 stainless steel butt weld fittings in this factory walkthrough. We demonstrate the 180-degree short radius return bend, show ASME B16.9 dimensional checks, NACE MR0175 compliance, and real production and testing steps. See how equal and reducing tees, elbows, and bends are made and inspected for petroleum, chemical, and power piping projects.