The American Petroleum Institute API (American Petroleum Institute)

ASTM (American Society for Testing Material) to the American Society for test materials DNV (Det Norske Veritas) Det Norske Veritas certification

DEP (Design and Engineering Practice) Design and Engineering Practice, the SHELL SHELL standard) EN (European Norm) European standard

NACE (National Association of Corrosion Engineer), the American Association of Corrosion engineers

COW pipe using furnace gas protection and submerged arc welding process manufacturing with one or two longitudinal seam or a spiral welded pipe products, in the process of welding, furnace, a gas protection weld was not completely submerged arc welding, melting.

COWH pipe using furnace gas protection and submerged arc welding process manufacturing with a spiral welded pipe products, in the process of welding, furnace, a gas protection weld was not completely submerged arc welding, melting.

COWL pipe using furnace gas shielded and burying ?