1.api 5l x52 black steel pipe line 2.API certificate 3.NDT,UT,ET, hydro tests 4.SGS Test 5.X42,X52,X56,X60... For Steel products enquiry, pls contact Ellie Huang, email: ellie(at)hnssd(dot)com, Skype: elliehljSeamless steel pipe Boiler seamless steel tube / Heat exchange pipeMechanical steel pupeSeamless Alloy steel tubeapi 5l x52 black steel pipe line Outer Diamter: 3/8" to 42" (16 - 426mm)Wall ...