The primary shoulder and secondary shoulder together form the dual-shoulder structure of the drill pipe joint, featuring the following key characteristics:
1. Significantly enhanced joint torsional resistance.
2. Optimizes stress distribution in the threaded section, thereby extending thread fatigue life and enhancing the overall service life of the drill pipe joint.
The WMDS, WMHT, and WMT series joints all adopt this dual shoulder structure, effectively addressing the insufficient torsional strength of API standard joints. Under identical material and ID/OD conditions:
WMDS joints exhibit 20%–30% higher torsional strength than API joints.
WMHT joints exhibit 25% to 40% greater torsional strength than API joints.
WMT joints demonstrate a substantial increase of approximately 70% in torsional strength compared to API joints.
Additionally, the WMQT series air seal couplings offer superior air sealing performance, with sealing capabilities up to 15,000 PSI.
