small size seamless real estate steel pipe SpecificationsChina StandardSteel GradeStandardseamless steel tubes and pipes for structural purposeGB/T8162-199910, 20, 35, 45, 40Mn2, 45Mn2, 27SiMn, 20Cr, 40Cr, 20CrMo, 35CrMo, 38CrMoA1, 50CrV, 30CrMnSiASTM A500-98ASTM A501-98ASTN A519-98JIS G3441-1994JIS G3444-1994Seamless steel tubes and pipes for..