Steel pipe Standard: ASTM A 312/A 312M Grade: TP304, TP304L, TP316L, TP321, TP316Ti, TP310S etc. Steel pipeStandard: ASTM A 312/A 312MGrade: TP304, TP304L, TP316L, TP321, TP316Ti, TP310S etc.Manufacture process: Cold draw or Cold roll, Annealed, and Pickled.Testing: Visual Check for surface, and Micrometer for the W.T and O.D.Spectral Analysis to test the Chemical Composition.Eddy Current Test or ...