High-Strength Butt Joint Method for Tubular Elements with Secondary Fixation

Abstract

The present utility model introduces a high-strength butt joint method for tubular elements, featuring secondary fixation. The technology is applicable in mechanical engineering, pipeline construction, the oil and gas industry (specifically for drill strings and casing pipes), and municipal utilities. The core of the method relies on a self-locking mechanical interlock of two mating tubular components using complementary helical (spiral) splines and corresponding grooves. The final rigid fixation is achieved via welding. The topological geometry of the helical splines is scaled according to the pipe diameter and wall thickness, ensuring an even, multi-axial spatial distribution of loads across the entire joint volume. This design provides a tight "metal-to-metal" mechanical fit capable of withstanding high internal distributed pressure structurally through the profile geometry. Furthermore, the massive helical elements allow for localized reinforcement of the wall thickness at the joint to strengthen critical nodes without reducing the pipe's internal flow cross-section. The proposed connection method provides significantly higher torsional and tensile strength due to the mechanical interlocking, which effectively unloads the fixing (welded) seam. This guarantees structural stability and drastically enhances the operational longevity of the pipeline under complex dynamic and static loads, making the assembly technology universal and highly reliable. 5 illustrations.