TCVN 6113-1996 Seamless and welded (except submerged arc-welded) steel tubes for pressure purposes-full peripheral ultrasonic testing for the detection of longitudinal imperfections
2008TCVN 6113-1996 Seamless and welded (except submerged arc-welded) steel tubes for pressure purposes-full peripheral ultrasonic testing for the detection of longitudinal imperfections