Superalloy Heat Treatment with Geometry-Dependent Quench Timing
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Solution Overview
Problem
Gas turbine components made of superalloys experience significant quench plastic strain accumulation and strain-induced deleterious phases due to location-specific temperature differences during heat treatment, which adversely affect creep life.
Innovation Solution
A heat-treatment process that incorporates a geometry-dependent and alloy-specific air transfer time to ensure all internal locations of the component are at or below the maximum quench temperature before active quenching, minimizing plastic strain accumulation and precipitate coarsening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat treatment is used without geometry-dependent air transfer time control, then the quenching process is simpler and faster, but significant quench plastic strain accumulation and strain-induced deleterious phases occur due to location-specific temperature differences
Solution Approach 1:
The patent applies preliminary action by implementing a controlled air transfer cooling phase before active quenching. During this preliminary phase, the component is allowed to cool uniformly in air for a geometry-dependent time period, ensuring that internal locations reach appropriate temperatures before the rapid quench begins. This preliminary cooling action prevents thermal shocks and strain accumulation that would otherwise occur during direct quenching.
Solution Approach 2:
The patent applies dynamics by making the air transfer time geometry-dependent and alloy-specific. Rather than using a fixed quenching procedure, the process dynamically adjusts the air transfer duration based on the component's geometric characteristics and material properties. This dynamic adjustment ensures optimal temperature distribution throughout the component before quenching, thereby improving creep life while accounting for variations in component design.
2Productivity
If rapid quenching is applied directly after heat treatment, then productivity is higher, but plastic strain accumulation and precipitate coarsening occur at internal locations
Solution Approach 1:
The controlled air transfer cooling serves as a preliminary action that prepares the component for quenching by achieving uniform temperature distribution. This preliminary phase prevents the formation of plastic strain and ensures uniform precipitate distribution throughout the component, including internal locations. The geometry-dependent duration of this preliminary phase is optimized to balance productivity with microstructure quality.
Solution Approach 2:
The patent applies parameter changes by adjusting the air transfer time based on component geometry and alloy composition. This parameter optimization ensures that the transition from heat treatment to quenching occurs at the optimal moment for each specific component type. By dynamically adjusting this timing parameter, the process achieves both high productivity and uniform microstructure without excessive cycle times.
3Reliability
If location-specific temperature control is implemented during heat treatment, then microstructure uniformity and creep strength are improved, but the heat treatment process becomes more complex
Solution Approach 1:
The controlled air transfer cooling acts as a preliminary action that achieves location-specific temperature control without requiring complex real-time monitoring systems. By allowing sufficient air cooling time before quenching, the process ensures that internal locations reach appropriate temperatures uniformly, creating optimal conditions for precipitate formation and improving creep strength through a relatively simple procedural adjustment.
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 process results in a microstructure with evenly distributed strengthening precipitates, enhancing creep strength and mechanical properties of the components.
Implementation Method 1
cooling the component from the predetermined solution temperature for a predetermined air transfer time
Implementation Method 2
cooling the component from the predetermined solution temperature for a predetermined air transfer time in the presence of air
Implementation Method 3
actively quenching the component
Data Source
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AI summary
Methods are provided for heat treating a component (10) comprised of a superalloy, along with component (10)s formed from the methods. The method includes heat treating the component (10) at a predetermined solution temperature for a predetermined solution time (42). Thereafter, the component (10) is cooled from the predetermined solution temperature for a predetermined air transfer time (44) in the presence of air, a gas, or a mixture of gases. Thereafter, the component (10) is actively quenched. The predetermined air transfer time (44) is sufficiently long such that a predetermined internal location (20) cools to a temperature that is below the maximum quench temperature before actively quenching the component (10).