Stabilizing Retained Austenite in Reference Pieces via Nano-Crystallization
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Solution Overview
Problem
Existing methods for manufacturing reference pieces to measure retained austenite are prone to measurement variations due to the potential transformation of austenite into martensite from impact or time lapse, affecting hardness and product dimensions.
Innovation Solution
A manufacturing method involving nano-crystallization of a metal member's surface followed by quenching and tempering to stabilize retained austenite, ensuring a uniform diffraction profile and minimizing measurement deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference piece is prepared for measuring retained austenite, then measurement of retained austenite can be performed, but the retained austenite may transform into martensite due to impact or time lapse causing measurement variations
Solution Approach 1:
The patent applies preliminary action by performing nano-crystallization on the metal member's surface before quenching and tempering. This pre-treatment creates a refined grain structure that stabilizes the retained austenite, preventing its transformation into martensite during subsequent storage or measurement processes, thereby ensuring measurement reliability
Solution Approach 2:
The patent employs parameter changes by controlling the quenching and tempering conditions after nano-crystallization. By optimizing the heating temperature, holding time, and cooling rate during heat treatment, the patent achieves a stable microstructure with controlled retained austenite content that resists temporal changes and impact-induced transformation
2Quantity of substance
If quenching is performed to obtain retained austenite, then austenite remains in the metal, but the retained austenite is unstable and transforms into martensite over time
Solution Approach 1:
Nano-crystallization is performed as a preliminary treatment before quenching to create a refined grain structure. This pre-treatment stabilizes the austenite phase by reducing grain size and increasing grain boundary density, which prevents the retained austenite from transforming into martensite during subsequent storage
Solution Approach 2:
The patent creates a composite microstructure consisting of nanocrystalline regions with retained austenite and tempered martensite. This composite structure, achieved through the combination of nano-crystallization and heat treatment, provides both the desired amount of retained austenite and enhanced stability against transformation
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 method produces a stable reference piece with reduced measurement variations, maintaining a consistent austenite ratio and resisting temporal changes, thus enhancing the accuracy of retained austenite measurement.
Implementation Method 1
performing nano-crystallization on at least a portion of a surface of the metal member
Implementation Method 2
performing quenching and tempering a metal member after performing nano-crystallization
Implementation Method 3
when the steel is quenched, that is, when the steel is rapidly cooled after the temperature of the γ region is maintained
Implementation Method 4
performing quenching and tempering a metal member
Data Source
AI summary
The manufacturing method of the reference piece for measuring retained austenite includes performing quenching and tempering a metal member after performing nano-crystallization on at least a portion of a surface of the metal member.