Tubular Threaded Joint Lubricating Coating for Seizure Resistance
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Solution Overview
Problem
Existing tubular threaded joints for oil country tubular goods face challenges in maintaining seizure resistance and gastightness without using compound grease, which poses environmental and health risks, and suffer from reduced torque resistance and potential shoulder portion yield during high-torque fastening.
Innovation Solution
A tubular threaded joint with a lubricating coating composed of melamine cyanurate, a basic metal salt of an aromatic organic acid, and additional components like pine resin-based materials, wax, and lubricating powder, applied to the contact surfaces of the pin and box, providing excellent seizure resistance, gastightness, and high torque resistance without harmful heavy metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compound grease containing heavy metal powders is applied to the contact surface, then seizure resistance and sliding properties are improved, but environmental harm and health risks increase
Solution Approach 1:
The patent removes harmful heavy metal powders (lead, zinc, copper) from the lubricating composition while maintaining the essential lubricating function through alternative organic-based compounds, thereby eliminating environmental and health hazards associated with compound grease
Solution Approach 2:
The invention changes the chemical composition parameters of the lubricating material from heavy metal-based compound grease to an organic-based system containing melamine cyanurate and basic metal salt of aromatic organic acid, achieving comparable or superior performance without harmful substances
2Reliability
If high torque is applied during fastening to ensure gastightness, then sealing performance is improved, but shoulder portion yield and structural damage occur
Solution Approach 1:
The lubricating coating is applied in advance to the contact surfaces before fastening, creating a protective layer that reduces friction and prevents galling during the high-torque fastening process, thereby allowing achievement of gastightness without exceeding the shoulder portion's strength limits
Solution Approach 2:
The lubricating composition acts as a cushioning layer between the contacting surfaces, absorbing and distributing the extreme pressure and shear stress generated during high-torque fastening, preventing direct metal-to-metal contact that would lead to shoulder portion yield
3Reliability
If compound grease is applied to the contact surface, then lubrication is improved, but the working environment and working efficiency deteriorate
Solution Approach 1:
The lubricating coating is designed to be applied once and provide self-lubricating properties throughout the service life of the threaded joint, eliminating the need for repeated applications and reducing maintenance requirements, thereby improving working efficiency while maintaining excellent lubrication performance
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 effectively prevents shoulder portion yield and maintains lubricating performance even under high torque conditions, ensuring stable metal-to-metal sealing and reducing environmental impact by eliminating the need for compound grease, while also offering anticorrosive properties.
Implementation Method 1
a lubricating coating which contains melamine cyanurate and a basic metal salt of an aromatic organic acid... providing excellent seizure resistance
Implementation Method 2
The lubricating coating is formed using a composition which contains melamine cyanurate and a basic metal salt of an aromatic organic acid
Implementation Method 3
offering anticorrosive properties
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Provided is a composition for forming a lubricating coating to a tubular threaded joint. The composition contains a melamine cyanurate, a basic metal salt of an aromatic organic acid, and one or more kinds selected from the group consisting of a pine resin-based material, a wax, a metal soap, and a lubricating powder.