Co-P Alloy Nut Coating for Pipe Joint Torque Control
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Solution Overview
Problem
Existing pipe joints with silver-plated nuts face issues of increased tightening torque and generation of fine particles during repeated mounting and demounting, leading to potential particle entry into piping systems.
Innovation Solution
A pipe joint design featuring a nut with a Co—P alloy metal coating on its inner surface, combined with a fluorine coating, which maintains consistent tightening torque and prevents particle generation, using materials like stainless steel and employing electroless plating or vacuum deposition methods for the Co—P alloy, and a retainer configuration to prevent external particle entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If silver plating is applied on the inner surface of the nut to prevent seize and galling, then the ease of operation is improved, but fine particles are generated by being rubbed off during repeated mounting and demounting
Solution Approach 1:
The invention changes the material parameter of the coating from silver to Co-P alloy, fundamentally altering the wear characteristics. The Co-P alloy coating maintains the low friction properties needed for easy operation while generating no fine particles during repeated mounting and demounting operations
Solution Approach 2:
The invention uses a composite structure combining Co-P alloy metal coating with fluorine coating. The Co-P alloy provides abrasion resistance and prevents seize, while the fluorine coating layer prevents particle generation and entry into piping, creating a multi-functional protective system
2Productivity
If the number of mounting and demounting operations is increased, then the productivity is improved, but the tightening torque increases significantly with silver-plated nuts
Solution Approach 1:
The invention changes the coating material parameter from silver to Co-P alloy, which fundamentally alters the friction characteristics. This material substitution allows repeated mounting and demounting operations to be performed without significant increase in tightening torque, maintaining consistent operational properties
3Ease of operation
If silver plating is used to reduce tightening torque, then the ease of operation is improved, but abrasion resistance is insufficient compared to Co-P alloy coating
Solution Approach 1:
The invention creates a composite coating system where the Co-P alloy metal coating provides the abrasion resistance (Vickers hardness of 500 or higher, several times that of silver plate), while the fluorine coating layer maintains low friction characteristics for easy operation with consistent tightening torque
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 Co—P alloy metal coating with fluorine coating provides superior abrasion resistance and maintains low tightening torque, preventing fine particle generation and entry into piping systems, while ensuring reliable mounting and demounting performance comparable to silver-plated nuts.
Implementation Method 1
The Co—P alloy metal coating may be formed by, for example, electroless plating
Implementation Method 2
instead, may be formed by vacuum film formation by using Vacuum Deposition method or Spattering Method
Implementation Method 3
a fluorine coating is applied on the surface of the alloy metal coating
Data Source
AI summary
A pipe joint includes first and second joint members having fluid channels communicating with each other, an annular gasket to be interposed between abutting end surfaces of the both joint members, and a nut configured to couple the joint members. The nut is provided with an inner surface treated layer. The inner surface treated layer includes a Co (cobalt)-P (phosphorous) alloy metal coating provided on an inner surface of the nut and a fluorine coating provided on the surface of the alloy metal coating.