METHOD OF DETECTING BAINITE IN STEEL Russian patent published in 2020 - IPC C23F1/28 G01N33/20 

FIELD: chemistry.

SUBSTANCE: invention relates to metallographic analysis of structural components of steel of predominantly bainitic type. Method involves preparing sample surface for etching, chemical etching of analysed surface in etching agent, washing in running water and drying in air flow, detecting areas of bainite using an optical microscope, identifying an image using an analyser, fixing and recording using high-resolution optics. As investigated material there used is structural alloyed steel of type H2G2S2MF after formation of lower needle-like morphology of bainite at isothermal holding during hardening, etching involves using a LePera etchant consisting of 50 ml of 1 % aqueous solution of Na₂S₂O₅ and 50 ml of 4 % picric acid in ethyl alcohol, in which ethyl alcohol is used of not less than 95 %. In process of washing and drying of analysed surface, oxide film is stored on etching surface, controlling and optimizing time for detecting a clear image of areas of placing bainite needles and detecting α- and γ -phase is bainite substructures.

EFFECT: invention provides complete information on beinite needle morphology - lower bainite, in the entire range of its formation in isothermal exposures T_ISO = 375–200 °C, in steels of system of alloying H2G2S2MF, related to systems with hard-separated components and phases at detection and identification of them using optical microscope.

1 cl, 6 dwg