METHOD FOR ASSESSING THE IMPACT STRENGTH OF PRODUCTS FROM STRUCTURAL STEEL HARDENED TO BAINITE Russian patent published in 2023 - IPC G01N27/72 

FIELD: assessment of the impact strength of structural steel products hardened to bainite.

SUBSTANCE: batch of indestructible standards is manufactured, which is subjected to isothermal hardening in the entire bainitic interval and in the entire time interval of transformation, determination of the amount of residual austenite in the reference samples after heat treatment by a non-destructive method, comparison of the relationship between the properties of residual austenite and the level of impact strength, building a single diagram with graphs of the dependence of the properties of residual austenite on the temperature and time of isothermal hardening of standards and determining their impact strength, while determining the amount of residual austenite in standard samples after isothermal hardening is carried out by a non-destructive magnetic method by measuring the saturation magnetization in a ballistic magnetometer, cooling of standards is carried out in liquid nitrogen at a temperature of -196°C until this temperature is fully reached, they are heated to room temperature, the amount of residual austenite after heating is determined again using the magnetic method, the thermal stability of residual austenite is calculated by comparing its amount before and after treatment in liquid nitrogen, single diagram is used to construct graphs of the dependence of residual austenite thermal stability, correlating with the level of impact strength in the standards, the level of impact strength is obtained on the graph according to the value of the thermal stability of the retained austenite of the controlled product in liquid nitrogen when compared with the thermal stability of the retained austenite of the standard.

EFFECT: providing the possibility of assessing impact strength and service life by non-destructive testing of serial products of small size, mainly from medium-carbon structural steels, hardened to bainite with isothermal exposure.

1 cl, 3 dwg