DOUGLAS BROTHERS STANDARDS FOR STAINLESS STEEL PIPE FABRICATION
All pipes and fittings are manufactured from stainless steel sheet or plate to ASTM A-240 standards. Material 10 gauge and lighter will have No. 2D or better finish, material 3/16″ and heavier will have No. 1 finish. Type of stainless steel shall be specified by the customer.
Welding procedures, welders and welding operators meet the requirements of ASME Code Sec. IX. Welding procedures are carefully established and tested to achieve full penetration welding. The longitudinal welds in pipes and fittings are made either by the automatic GTAW with or without filler metal, the automatic GMAW (spray transfer) or the automatic plasma arc welding process. Gas back-up protection is provided in all cases.
The process for stainless steel pipe fabrication includes carefully die-formed or rolled true to dimension and round within a tolerance of plus or minus 1/16″. The two edges of sheet are brought in line so as not to leave a shoulder on the inside of the pipe. Ends of pipe and fittings are to be perpendicular to the longitudinal axis. Pipes shall be straight within maximum of 1/8″ deviation over 10-feet. The consumables are of a grade similar to the base material and always of the extra low carbon grade. Weld reinforcement does not exceed 0.063″ at the inside surface and 0.094″ at the outside surface. Surface finish of welds is left as welded. However, grinding and polishing can be done upon request.
All pipes and fittings are pickled in an acid solution and rinsed thoroughly with clean water.
Our aim is to produce a good quality product. To this end, tools, dies, jigs, and fixtures used throughout the manufacturing process are periodically inspected in order to ensure that dimensional tolerances are observed. All pipes, fittings and assemblies are visually inspected and random radiographic examination of welds is undertaken to the extent necessary to ensure excellent quality welding.
Pressure ratings of pipe and fittings are listed under the Pipe and Fittings Specification Page