Pipe Threaded Connection Coatings for Stable Torque and Gastightness
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Solution Overview
Problem
Conventional threaded connections for pipes face challenges in achieving a high fastening torque while maintaining galling resistance and gastightness, with fluctuations in torque requiring frequent adjustments to equipment, leading to reduced operational efficiency.
Innovation Solution
A threaded connection design featuring a shoulder part plating layer with a high friction coefficient and a non-shoulder part plating layer with a low friction coefficient, applied to the pin and box components, allowing for a large delta torque and efficient fastening at both conventional and higher torque levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compound grease containing heavy metal is used to enhance galling resistance, then galling resistance is improved, but environmental harm increases due to heavy metal contamination
Solution Approach 1:
The invention extracts and removes the harmful heavy metal component from the grease formulation while retaining the beneficial lubricating and galling-resistant properties through alternative additive packages that do not contain Pb, Cd, Hg, or other toxic heavy metals
Solution Approach 2:
The invention changes the chemical composition parameters of the grease by replacing heavy metal-based anti-wear additives with organic or metal-free alternatives, thereby maintaining galling resistance while eliminating environmental harm
2Force
If fastening torque is increased to meet deeper oil well requirements, then fastening capability is improved, but torque fluctuation increases requiring frequent equipment adjustments
Solution Approach 1:
The invention applies different friction coefficient characteristics to different regions of the threaded connection - a high friction coefficient in the shoulder part region and a low friction coefficient in the thread engagement region - thereby achieving stable torque transmission with reduced fluctuation
Solution Approach 2:
The invention changes the friction coefficient parameter distribution along the threaded connection interface, creating a gradient from high friction at the shoulder to low friction in the thread zones, which stabilizes the torque characteristics during fastening operations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a large delta torque, enabling efficient fastening at a torque equivalent to conventional connections while allowing for higher torque levels without excessive deformation, thus enhancing operational efficiency and gastightness.
Implementation Method 1
The shoulder part plating layer has an outermost layer formed of a high friction coefficient plating layer
Implementation Method 2
The non-shoulder part plating layer has an outermost layer formed of a low friction coefficient plating layer having a coefficient of friction lower than a coefficient of friction of the high friction coefficient plating layer
Data Source
AI summary
A threaded connection for pipes includes a pin, a box, a shoulder part plating layer, and a non-shoulder part plating layer. The shoulder part plating layer has an outermost layer formed of a high friction coefficient plating layer, and is arranged on a pin side shoulder part and/or a box side shoulder part. The non-shoulder part plating layer has an outermost layer formed of a low friction coefficient plating layer having a coefficient of friction lower than a coefficient of friction of the high friction coefficient plating layer, and the non-shoulder part plating layer is arranged on at least one of a pin side thread part, a pin side metal seal part, a box side thread part, and a box side metal seal part.