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index

1. Purposes
Well drilling for oil.
2. Category
By SY/T6194-96 "oil pipes" Thread casing and its short-collar and long thread casing and its coupling the two.
3. Specifications and quality of appearance
(1) Domestic by SY/T6194-96 casing, not the length of casing length, the scope of 8-13 m. But not less than 6 m of the casing can provide, their number should not exceed 20 percent.
(2) the internal and external casing surface may be folded, the profiling, separation, crack, rolling and folding and scarring. These deficiencies should be entirely removed, clearing the depth no more than nominal thickness of 12.5 percent.
(3) collar outer surface may be folded, the profiling, separation, crack, rolling packs, scarring, and other defects.
(4) casing collar and thread the surface should be smooth, do not allow a burr, and tearing up enough to thread strength and the impact of disruption closely connected to other defects.