Stainless Steel SS AISI 304 / 304L Pipe & Tubing is stocked and supplied in seamless & welded form in Round and Square as per ASTM A269,A249,A312,A358,A213321 Stainless steel Pipe/Tube-Stainless steel Pipe/Tube 321 small diameter seamless stainless steel pipe tube321 stainless steel pipe . Seamless steel pipe (GB14976-2002) is used to manufacture superheated steam pipes , boiling water pipes and locomotive boiler superheated steam pipes , large smoke pipes , small smoke pipes and arch brick pipes of various structures.