--- type: "WebPage" title: "Measurement of retained austenite in steels by X-ray diffraction (ASTM E975-22 standard) in the laboratory" description: "You wish to measure the austenite retained in your steels by DRX according to the ASTM E975-22 standard What is retained austenite in steels?  Austenite is a crystalline phase of iron (and some steels) that appears when the steel is..." resource: "https://filab.fr/en/our-services/our-analysis-services/chemical-analysis-laboratory/measurement-retained-austenite-steels-astm-e975-22/" tags: ["EN", "pll_68cbc306d97a7", "Anaïs DECAUX"] timestamp: "2026-01-09T14:05:58Z" published: "2025-09-18T08:59:05Z" language: "en" author: "Laure Durieux" --- # Measurement of retained austenite in steels by X-ray diffraction (ASTM E975-22 standard) in the laboratory ## You wish to measure the austenite retained in your steels by DRX according to the ASTM E975-22 standard ### What is retained austenite in steels? ![inox](https://filab.fr/wp-content/uploads/2024/02/acier-inoxydable-2.png)   **Austenite** is a **crystalline phase of [iron](https://filab.fr/en/our-services/our-analysis-services/metallurgical-analysis-laboratory/iron-alloys-analysis-at-filab-laboratory.md)** (and some [**steels**](https://filab.fr/en/our-services/our-analysis-services/metallurgical-analysis-laboratory/laboratory-of-analysis-and-expertise-of-steels.md)) that appears when the steel is heated to high temperatures. - It is a **face-centered cubic (FCC)** structure of iron that can **dissolve a large amount of carbon**. - It typically exists in a temperature range **between 723°C and approximately 912°C** (depending on the steel's composition). - Upon cooling, austenite transforms into other phases (martensite, ferrite, pearlite, etc.), unless it remains **trapped**: this is called **retained austenite**. ### Why measure retained austenite? Retained austenite is a metastable phase present in certain quenched and tempered steels. Its percentage directly influences: - **Mechanical performance** ([hardness](https://filab.fr/en/our-services/our-expertise-services/mechanical-laboratory-test/hardness-analysis-and-measurement-laboratory.md), toughness, [wear](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-failures/laboratory-analysis-wear.md) resistance). - **Dimensional stability** of parts in service. - **[Fatigue](https://filab.fr/en/our-services/our-expertise-services/mechanical-laboratory-test/endurance-test-fatigue-testing.md) and impact resistance behavior**. Excess retained austenite can lead to deformation or loss of performance, while precise control ensures the **quality and reliability** of your steels. ## X-ray diffraction (XRD) analysis according to ASTM E975-22 The **[ASTM E975-22](https://store.astm.org/e0975-22.html)** standard defines the method for quantifying retained austenite using **[X-ray diffraction (XRD)](https://filab.fr/en/our-technical-resources/x-ray-crystallography-laboratory-xrd.md)**. This technique allows for: - **Direct quantitative analysis** of **crystallographic phases**. - **Non-destructive** measurement, suitable for finished parts. - **High accuracy**, even for low levels (<1%). ## The FILAB laboratory measures the austenite retained in your steels according to the ASTM E975-22 standard ### Why choose FILAB for measuring retained austenite in steels? Equipped with a state-of-the-art [analytical facility](https://filab.fr/en/our-technical-resources.md) and a team of experts dedicated to [metallurgical analysis](https://filab.fr/en/sectors-of-activity/laboratory-metallurgy-steelmaking-analysis.md), the FILAB laboratory supports manufacturers in resolving their problems related to steel analysis. ### The principle of XRD in the measurement of residual austenite according to ASTM E975-22 **XRD analysis** is a powerful analytical technique based on the phenomenon of X-ray diffraction by the atoms of a material. When X-rays encounter the crystalline structure of a sample, they are scattered at specific angles based on the arrangement of atoms within the material. By measuring the intensities and diffraction angles, it is possible to determine the crystal structure and phases present in the sample, including r**etained austenite**. ## Our other steel analysis services [Metallographic examination](https://filab.fr/en/our-services/our-analysis-services/metallurgical-analysis-laboratory/examination-metallographic-section-laboratory.md) of steel [Weld analysis](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-failures/laboratory-analysis-welds.md) on steel Study of fracture surfaces on steel [Study of ageing](https://filab.fr/en/our-services/our-analysis-services/polymer-materials-analysis-laboratory/laboratory-material-testing/filab-accelerated-ageing-test-laboratory/) (corrosion, surface alteration, etc.) on steel [Metallurgical expertise](https://filab.fr/en/our-services/our-analysis-services/metallurgical-analysis-laboratory.md) [Analysis of stainless steels in accordance with standard NF EN 10088](https://filab.fr/en/our-services/our-analysis-services/metallurgical-analysis-laboratory/laboratory-analysis-of-your-stainless-steels-according-to-nf-en-10088-standards.md) [Stainless steel analysis according to ISO 3651-1](https://filab.fr/en/our-services/our-analysis-services/metallurgical-analysis-laboratory/stainless-steel-analysis-iso-3651-1.md) [Thickness measurement](https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization/surface-coating-thickness-measurement.md) of steel [Study of corrosion](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-deposit-contamination/laboratory-expertise-and-analysis-of-corrosion.md) resistance on steel [Analysis and characterization](https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization.md) of steel surfaces (roughness, defects, etc.) Analysis [Alloy composition](https://filab.fr/en/our-services/our-analysis-services/metallurgical-analysis-laboratory/metallic-alloy-analysis-laboratory.md) [Study of microstructures](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-failures/laboratory-of-microstructure-analysis-of-materials.md) steel material Analysis of hardened martensitic steel type APX4 ## FAQ What is retained austenite? Retained austenite is a crystalline phase of iron that can persist after heat treatment of steel (hardening, tempering). Its quantity directly influences the hardness, dimensional stability and mechanical strength of the material. Which sectors are affected by the measurement of retained austenite in steels according to the ASTM E975-22 standard? - **Automotive & aeronautics industries**: inspection of critical parts (gears, shafts, bearings, etc.). - **Nuclear & energy**: securing components under harsh conditions. - **Medical & implantable devices**: mastering the microstructure of metal alloys. - **Subcontractors in heat treatment & steelmaking**: process validation. What are the characteristics of retained austenite? - Austenite gives steels good ductility (the ability to deform without breaking). - Its transformation into martensite during quenching is the source of the hardness of hardened steels. - Too much retained austenite can cause problems (dimensional instability, drop in hardness), while careful control can improve certain properties (impact strength, impact resistance). In summary, austenite is a specific form of iron that plays a key role in the heat treatment and performance of steels. Why is it important to measure retained austenite? - Ensure compliance with specifications and industry standards. - Optimize heat treatments to achieve expected mechanical properties. - Avoid in-service defects: deformation, cracking, and loss of hardness. What is the reference standard? The measurement is carried out according to the international standard **ASTM E975-22**, which defines the method for quantifying retained austenite by X-ray diffraction. What are the benefits of XRD? - Non-destructive: the analyzed part is not altered. - High precision: low levels (<1%) can be detected. - Applicable directly to finished parts.