Standards and Grades: ASTM A106 Grade A/B, A53 Gr A& B, St37, 10#, 20#, 45#, ... ,APISPEC5L,API5CT,ASTMA53/A106,JIS,BS1387,etc.3.Steel Grade: Q235B,Q345B,API5L Grade B,X42~X80,16Mn,20#ST37~ST52 etc ... orders as customers requestsAnti-corrosion and high-temperature resistant with black paintingAll the production process are made under the ISO9000.