| 摘要 |
The threading of a threaded tubular element comprises at least one tangential multiple radius junction zone (21) at the thread root, in particular on the load flank side (13). This zone (21) comprises a principal arc (23) with a radius (rP1) where the support circle cuts the flank (13) at a point (PRF1). The tangent at (PRF1) to this circle makes a strictly positive angle (D) with the flank (13). The secondary arcs (25, 27) with radii (rS1 and rT1) which are lower than (rP1) effect the tangential junction of the principal arc on one side to the flank (13) and on the other side to the thread root (19). Radius (rP1) is larger than that (rH1) of the standard circle (29) which passes through (PRF1) and which would alone constitute a tangential junction zone. Such a threaded element provides a threaded tubular connection which incorporates good resistance to both static and cyclic stresses.
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