High Temperature Thread Locking Compound for Gas Turbine Engines
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Solution Overview
Problem
Existing locking compounds for threaded fasteners fail to provide adequate torque resistance at high temperatures, such as those encountered in gas turbine engines, where temperatures exceed 450 degrees Fahrenheit, leading to bolt loosening and potential damage.
Innovation Solution
A locking compound comprising a substantially pure, non-chromated aluminum pigmented compound suspended in a water-based inorganic binder is applied directly to the threads of a threaded fastener or hole, providing increased torque resistance by being present between at least 5% of the mated threads, and is capable of withstanding temperatures exceeding 900 degrees Fahrenheit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional locking compounds are used, then torque resistance is provided at low temperatures, but torque resistance is lost at high temperatures exceeding 450 degrees Fahrenheit
Solution Approach 1:
The patent changes the chemical composition parameters of the locking compound by using water-based inorganic binders (such as silicates, phosphates, or zinc oxalate) instead of organic binders. This parameter change allows the compound to maintain structural integrity and torque resistance at temperatures exceeding 900 degrees Fahrenheit, resolving the contradiction between temperature resistance and torque resistance reliability.
Solution Approach 2:
The patent creates a composite locking compound material combining water-based inorganic binders with aluminum pigmented compound and corrosion inhibitors. This composite structure provides both high-temperature stability from the inorganic binder and enhanced corrosion resistance, maintaining torque resistance reliability across extreme temperature ranges where conventional organic-based compounds fail.
2Temperature
If mechanical bolt locks are used instead of locking compounds, then high temperature torque resistance is achieved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical locking systems (such as lock washers, nylon inserts, or tab locks) with a chemically-based locking compound system. This substitution eliminates complex mechanical components while providing equivalent or superior torque resistance at high temperatures through the thermal-stable inorganic binder chemistry, thereby reducing device complexity.
Solution Approach 2:
By changing the binder chemistry from organic to water-based inorganic systems, the patent achieves high-temperature mechanical properties without requiring additional mechanical locking features. The chemical composition parameters are optimized to provide sufficient shear strength and torque resistance purely through the compound's material properties.
3Temperature
If aluminum pigmented compound is used for high temperature resistance, then torque resistance is maintained, but corrosion protection may be compromised
Solution Approach 1:
The patent develops a composite formulation integrating aluminum pigmented compound with water-based inorganic binders and specific corrosion inhibitors. This multi-component composite provides synergistic effects where the aluminum pigment contributes to high-temperature stability, the inorganic binder provides structural integrity, and corrosion inhibitors protect against galvanic and environmental corrosion, resolving the contradiction between temperature resistance and corrosion protection.
Solution Approach 2:
The locking compound is designed to perform multiple functions simultaneously: providing torque resistance at high temperatures, preventing corrosion of the fastener and threaded hole, and maintaining these properties across a wide temperature range. The universal formulation eliminates the need for separate protective measures, addressing both temperature resistance and corrosion resistance in a single application.
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 increases torque resistance, maintaining bolt lock integrity even at extreme temperatures, and also inhibits corrosion, facilitating easy removal during maintenance, while being environmentally friendly.
Implementation Method 1
a substantially pure, non-chromated aluminum pigmented compound suspended in a water-based inorganic binder
Implementation Method 2
presence of the locking compound between the mated fastener threads and the hole threads causes an increase in running torque
Data Source
AI summary
According to the present disclosure, a method for securing a threaded fastener in a threaded hole includes directly applying a locking compound to at least a portion of threads to be mated on either the threaded fastener or the threaded hole. The locking compound includes a substantially pure, non-chromated aluminum pigmented compound suspended in a water-based inorganic binder with temperature resistance in excess of 900 degrees Fahrenheit (about 482 degrees Celsius). The threaded fastener is threaded into the threaded hole after applying the locking compound on the threads to be mated.