Lambda provides retained austenite measurement using x-ray diffraction. X-ray diffraction is considered to be the most accurate method of determining the amount of retained austenite in steels. Lambda is the only accredited independent laboratory that uses Bragg-Brentano diffractometers for measurement of retained austenite, as required by ASTM and SAE.
Features of retained austenite measurement:
How Does Retained Austenite Affect Performance?
Austenite can transform in service as a result of thermal cycles, plastic deformation, or shock. Shot peening, for example, will transform the retained austenite on the surface of gear teeth. Exposure to extreme cold renders the retained austenite increasingly unstable as the temperature diminishes. The transformation of austenite to ferrite involves a nominal 4% volume increase that can lead to seizure and excessive interference in precision gearing and bearings. It is important to characterize the retained austenite to ensure safe operation of certain critical pieces.
Most of the diffractometers on the market today are equipped with position sensitive detector (PSD) based systems for speed and portability. These systems cannot be calibrated by direct calculation of the relative phase intensities and must use reference standards that usually are not of the same structure as the test articles. For the reasons described above, any difference in unit cell dimension between the calibrating austenite standard and the test article will result in a significant error in calibration of the measurement system. It is therefore critical that the reference standards are of the same alloy and structure as the samples being tested on PSD based systems.
Lambda can provide rigorous certification of retained austenite standards per ASTM and SAE. Standards can be manufactured from the same structure and alloy as the test article to eliminate the associated errors discussed above.
For any questions you have about our austenite testing facilities or to send samples please contact us now at (800) 883-0851 or by email.
8620 Steel Carburized Gear Tooth