| 摘要 |
A high-strength threaded joint, preferably for lined tubes, comprising: a coupling (1) with a threaded inner surface along its whole length with ends defined as female; and a pair of tubes (T), each of them having ends (2), defined as male, with an external threaded surface and a thread-free end defined as a nose (N); said joint having an 8 round API thread profile (3), according to standard API 5B, with a diameter interference from 0 to 2 mm; where each of said noses (N) comprising: an upper portion formed by a thread bevel (B) with a slope of substantially 65 degrees, which continues on a first rounded area (51) with a first radius of curvature (R1) of 1.5 mm; and a lower portion including a second rounded area (92) with a second radius of curvature (R2) of 1.5 mm; said thread bevel overlapping (B) with said thread (3) and said first rounded area (S1) extending from said thread bevel (B) up to a point of its curvature where a tangential line is perpendicular to the longitudinal axis (X) of said tube (T), and said second rounded area extending (S2) from a point of its curvature where a tangential line is perpendicular to the longitudinal axis (X) of said tube (T) up to th e inner surface of said tube (T). |
