Some steel based alloys, when quenched after being overheated, form a given quantity of residual or retained austenite. Being able to control the martensite/austenite ratio of the steel means controlling the quality of the material. Sigmametry is a measurement technique for QC of materials from production. It is based the ferromagnetic properties of martensite. It is commonly used by companies worldwide, as it is a very simple and quick method. We will review and compare different retained austenite measurement methods using sigmametry.This an extract of our documentation, please register to have access to all documentation.