API 5L Gr. B/A106 Gr. B Seamless Line Pipe

　　API 5L Gr. B/A106 Gr. B Seamless Line Pipe， this is the distinction between the quality level, from A to E in turn increased, mainly due to phosphorus and sulfur and other micro-element content of the impact of different temperature difference, The chemical composition of different mechanical properties.

　　Q345D seamless steel pipe of a material. Q represents the yield of this material, the back of the 345, is the yield value of this material, in 345 or so. And the yield value decreases as the thickness of the material increases.