... .10, GB 3087, GB/T 8162 ,GB/T8163 10# 20#, 45#,3.Outer Diameter2-20 mm4.Wall Thickness21.3-810 mm5 ... (B,C) Q235B,Q345B,16Mn, 10#.20#,45# Gr.2,Gr.3; ST37,ST42,ST52;Gr.B,X42,X46,X52,X56,X60,X65,X70 ... Netherlands,Belgium, etc13.CertificatesAPI 5L; ISO9001:2000 ASTM A106/A53 Gr.B seamless steel pipe