Technical Requirements for Production of Oil Casing Pipes

1) the domestic casing conforms to SY / t6194-96, the casing length is not fixed, and the range is 8-13m. However, casings of not less than 6 m may be provided and the number of casings shall not exceed 20%.
(2) the internal and external surfaces of the shell shall be free of wrinkles, fine lines, separation layers, cracks, wrinkles and crusts. These defects shall be completely removed to a depth not exceeding 12.5% of the nominal wall thickness.
(3) the external surface of the coupling shall be free of defects such as folding, fine grain, separation, crack, rolling, skinning, etc.
(4) the surface of casing and connecting thread shall be smooth, and shall not be burred, torn and other defects sufficient to cause thread fracture and affect the strength and tight joint.