METHOD FOR DETECTING BAINITE IN STRUCTURAL STEEL Russian patent published in 2022 - IPC G01N33/20 

FIELD: metallurgy.

SUBSTANCE: invention relates to means of preliminary stereometric microanalysis using an optical microscope and can be used for detection and quantitative analysis of dispersed needle-like structure of lower bainite in steel, structure of which is formed during isothermal hardening. Method for detecting bainite in structural steel with a bainitic structure of “Х2Г2С2МФ” series involves preparation of a thin section, etching it in a reagent which forms an oxide film on the surface and detecting a phase composition, shooting in polarized light on a light microscope to obtain an image with a luminous bainitic alpha phase, dark gamma phase and dark martensite alpha phase, wherein at least two thin sections are prepared, the surface of one of which is parallel to the main deformation axis, and the other is perpendicular to the main axis of deformation, the etching of the thin sections is carried out in layers, the thin sections are surveyed at angles of rotation of the thin sections around their axis with difference of 45°, superimposing the obtained images on each other so that the structure elements coincide and all the bainite areas visible on each image are displayed on the final image, sections of bainite are selected and quantitative analysis of the disperse needle-like structure of lower bainite is carried out using an image processing program.

EFFECT: invention increases accuracy of determining lower bainite in steel using a light microscope.

1 cl, 1 tbl, 15 dwg, 4 ex