... 1/4"-24" Certificate: ISO, API Seamless Steel Tubes for low and Medium Pressure BoilersSpecificationsChina StandardSteel GradeStandardseamless steel tubesGB ... A519-98 JIS G3441-1994 JIS G3444-1994Seamless steel tubes and pipes forGB/T8163-199910, 20, Q295, Q345ASTM ... 1984seamless steel tubesAPI SPEC 5CTJ55, N80APIand pipesfor casingSeamless steel tubes forAPE SPEC 5LA, B, X42APIoil casing andtubing in ...