... Certificate: ISO9001, API 5L Perennial: stainless steel plate, seamless steel pipe, thick wall steel pipe, round steel, square tube, rectangular tube.Products: pipe: (GB/T8162-2008): (GB/T8163 ... T8162-2008), alloy tube, high pressure alloy pipe: (GB/T5310-2008) and a series of steel products.Material: 10#, 20#, 35#, ... 27SIMN, 37MN5, 35MN2V, 42CRMO, 40CR and other kinds of MN steel seamless steel pipe