Copper-Nickel-Tin Sucker Rod Coupling for Galling Resistance
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Solution Overview
Problem
Conventional sucker rod couplings made from steel or nickel alloys suffer from galling, corrosion, and mechanical integrity issues, leading to frequent failures and costly remediation in hydrocarbon extraction processes, particularly due to lack of intrinsic galling resistance and short service life.
Innovation Solution
Development of spinodally-hardened copper-nickel-tin alloy couplings with specific weight percentages of nickel and tin, providing high tensile strength, fatigue strength, fracture toughness, and corrosion resistance, along with grooved exterior surfaces to enhance fluid flow and reduce wear, formed through cold working and spinodal hardening processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional steel or nickel alloys are used for couplings, then high tensile strength is achieved, but galling resistance is poor leading to frequent failures
Solution Approach 1:
The invention changes the material parameters by using a copper-based alloy with specific composition (6-12% nickel, 4-10% tin, 0.5-2% zinc, 0.05-0.2% manganese, 0.05-0.15% silicon, and 85-92% copper) and applying spinodal hardening treatment to achieve both high tensile strength (75-120 ksi) and excellent galling resistance, resolving the contradiction between strength and reliability
Solution Approach 2:
The invention creates a composite microstructure through spinodal hardening, forming a two-phase alloy structure with distinct regions of different composition and properties. This composite material approach combines the advantages of copper (corrosion resistance, galling resistance) with nickel and tin (strength enhancement) to achieve both high tensile strength and reliability
2Reliability
If expensive surface treatments are applied to increase galling resistance, then galling resistance is improved, but maintenance costs increase due to periodic re-application
Solution Approach 1:
The copper-based alloy provides intrinsic galling resistance through its material composition and spinodal hardening treatment, eliminating the need for external surface treatments. The material serves its own protection function, providing long-term galling resistance without requiring periodic maintenance or re-application of coatings, thereby reducing maintenance costs
3Strength
If couplings are made from materials with high strength, then mechanical integrity is improved, but service life is reduced due to corrosion and galling
Solution Approach 1:
The invention optimizes the alloy composition parameters and applies spinodal hardening treatment to achieve a balance between strength and corrosion/galling resistance. The resulting material has tensile strength of 75-120 ksi while simultaneously providing excellent resistance to corrosion and galling, extending service life without sacrificing mechanical integrity
4Ease of manufacture
If conventional materials are used for couplings, then manufacturing simplicity is maintained, but frequent failures lead to costly remediation operations
Solution Approach 1:
The invention uses a copper-based alloy that can be manufactured using conventional metallurgical processes, maintaining manufacturing simplicity. The alloy is cast, machined, and formed using standard industrial techniques. The spinodal hardening treatment is applied through controlled heat treatment processes that are compatible with existing manufacturing infrastructure, while dramatically reducing failure rates through improved material properties
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 spinodally-hardened copper-nickel-tin alloy couplings exhibit improved galling resistance and mechanical integrity, significantly extending the service life of components, reducing maintenance costs, and preventing hydrocarbon leakage during hydrocarbon recovery operations.
Implementation Method 1
couplings made from a spinodally-hardened copper alloy
Implementation Method 2
Damage to the conduit caused by repetitive contact between the outer surface of the coupling and the inner surface of the conduit
Data Source
AI summary
A cold worked and spinodally-hardened copper alloy comprising from about 8 to about 20 wt % nickel, and from about 5 to about 11 wt % tin, the remaining balance being copper, and having a 0.2% offset yield strength of at least 75 ksi, is used to form a sucker rod coupling or subcoupling. Each coupling is formed from a core having two ends, each end having an internal thread. These box ends engage the pin of a sucker rod or other rod. The exterior surface of the core includes grooves running between the two ends.