1.ASTM A106/A53 GR.B 2.Outer diameter:10.3-914.4mm 3.Wall thickness: ... /A53/API 5L(2) Material: 10#, 20#, 16Mn, A106Gr.A/B/C,(3)Specification: O.D: 21.3mm-711.2 mm ... ,20GB3087-199910-530*2-40Over-heat pipe for low and medium pressure boiler, boiling water pipe, locomotive smoke pipe(big and small)Fluid pipe20, Q345GB/T8163-19998 ...