... 1, Seamless carbon tubes2,OD:20-325mm3, W.T.:2-50mm4, 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): ( ... , 42CRMO, 40CR and other kinds of MN steel seamless steel pipe