1) Sizes: 6" to 24 "
2) Standards: GB/T8163 Gr. B, ASTM A53 Gr. B, ASTM A106, ASTM A333, DIN1629/ 17175/2448, API5L Gr. B API 5CT, ASME B 36.10
3) Surface: Oiled or black painted to prevent rust
4) Marking: As per customer's requirement
Commonly used steel grade:
10 20 45 16Mn ST37.0 ST42.0 ST45.8 Q345 B