... -50mm4, Certificate: ISO9001, API 5L Perennial: stainless steel plate, seamless steel pipe, thick wall steel pipe, round steel, square tube, rectangular tube.Products ... /T5310-2008) and a series of steel products.Material: 10#, 20#, 35#, 45#, 20G, 20Gr-50Gr, 16Mn-45Mn, 27SiMn, ... 207-9Note: 10#, 20#3, 30#, 45#, 16MN, 27SIMN, 37MN5, 35MN2V, 42CRMO, 40CR and other kinds of MN steel seamless steel pipe