... GB/T8162 , GB/T8163 ,ASTM A53 ,ASTM A106 ,DIN1629 , API 5L Steel Grade GB/T8162 , GB/T8163:10#, 20#, 35#, 45#, 16MN(Q345B ... . B, GR. C ASTM A106 GR. A , GR. B, GR. C DIN 162 St 37.0, St 44.0, St 52.0 API 5L ... A B X42,X46, X52, X60, X65, X70, X80 ASTM A106 ... ,K55,N80,P110,L80/Gr.B X42,X46,X52,X56/X65,X70 and more. Certificate:API spac 5L/5CT,ISO9001:2000 Process method ...