Galling-Resistant Threaded Tubular Component Coating
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Solution Overview
Problem
Current solutions for preventing galling in threaded tubular components used in hydrocarbon wells, such as lubricants and surface treatments, face challenges including environmental pollution, high production costs, and difficulty in controlling homogeneity, particularly for chromium steels and on an industrial scale.
Innovation Solution
A coating process involving the deposition of a dry film with a crystalline mineral structure, primarily composed of non-reactive mineral salts, which enhances lubrication and frictional properties without altering the chemical nature of the metallic substrate, and can be applied to various alloys, including stainless steels, using alkaline silicates and supplemented with anticorrosion agents and solid lubricants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional grease coatings (API Bul 5A2 or 5A3) are used to protect threaded zones against galling, then galling protection is improved, but environmental pollution increases due to heavy metal content and grease ejection during makeup operations
Solution Approach 1:
The invention changes the chemical composition parameters of the coating by using inorganic salts (such as zinc chloride, calcium chloride, magnesium chloride) instead of traditional organic grease-based coatings containing heavy metals. This substitution maintains protective functionality while eliminating environmental pollutants, directly resolving the contradiction between galling protection and environmental pollution
Solution Approach 2:
The coating is designed as a consumable layer that can be easily applied and refreshed during maintenance operations. The inorganic salt coating provides sufficient protection for the service life required, and when depleted or contaminated, can be removed and reapplied without complex procedures, replacing the need for long-lasting but polluting traditional grease coatings
2Reliability
If phosphatation type treatments (zinc phosphatation, manganese phosphatation) are applied to enhance corrosion protection and adhesion, then corrosion resistance is improved, but manufacturing complexity and cost increase due to chemical attack processes and effluent management requirements
Solution Approach 1:
The invention extracts and eliminates the complex chemical conversion steps inherent in phosphatation treatments. Instead of using chemical attacks to form crystalline adhesive layers, the patent applies a simpler inorganic salt coating that achieves corrosion protection and adhesion through direct deposition and crystallization, removing the need for complex effluent management systems
Solution Approach 2:
The invention creates a simplified version of the protective function achieved by phosphatation. Rather than undergoing complex chemical transformations to form phosphate layers, the inorganic salt coating replicates the protective and adhesive functions through a simpler physical-chemical deposition process, achieving similar results with reduced manufacturing complexity
3Object-generated harmful factors
If multiple coating layers are applied to dispense with grease, then grease-free operation is achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
The invention extracts and eliminates the need for multiple coating layers by using a single inorganic salt coating application that achieves grease-free operation. This single-layer approach provides sufficient protection against galling without corrosion while avoiding the cumulative cost and complexity of applying multiple specialized layers
Solution Approach 2:
The inorganic salt coating is designed to perform multiple functions simultaneously: it provides lubrication for grease-free operation, corrosion protection through the nature of the salt crystals, and adhesion to the metal substrate. This multi-functionality in a single coating layer eliminates the need for separate specialized layers, reducing manufacturing cost and complexity
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 solution significantly reduces galling risk, increases performance, and decreases production costs while being environmentally friendly, maintaining the chemical integrity of the substrate and providing improved adhesion and retention of lubricants, demonstrated through high specific surface area and effective frictional performance in makeup and breakout operations.
Implementation Method 1
evaporating off said solvent in order to obtain a dry film with a crystalline structure having a high specific surface area
Implementation Method 2
obtain a dry film with a crystalline structure having a high specific surface area principally constituted by one or more mineral salts
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A galling-resistant threaded tubular component for drilling or operating hydrocarbon wells has at one of its ends (1; 2) a threaded zone (3; 4) produced on its external or internal peripheral surface depending on whether the threaded end is male or female in type, with at least one portion of the threaded zone (3; 4) being coated with a dry film with a crystalline structure with a high specific surface area principally constituted by one or more mineral salts which are not reactive towards metals. It also concerns a process for coating such a component using a dry mineral film with a crystalline structure having a high specific surface area principally constituted by one or more mineral salts which are not reactive towards metals.