DETERMINING FERRITE PHASE FRACTION AFTER HEATING OR COOLING OF STEEL STRIP Russian patent published in 2019 - IPC C21D1/55 G01N27/72 C21D8/02 C21D9/46 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy. To quickly determine the proportion of the ferrite phase in steel strip (2) in online mode, the method comprises the following steps: measuring width w₁ and temperature T₁ of steel strip (2), wherein steel strip (2) comprises ferrite phase fraction x_α1 during the measurements, heating or cooling steel strip (2), wherein in steel strip (2) when heating a phase conversion α→ γ from the ferrite state α into the austenitic state γ at least in part and when cooling a phase conversion from austenitic state γ into ferrite state α at least in part occurs, measuring width w and temperature T of steel strip (2) converted at least in part and determining ferrite phase fraction x_α of formula

(I), wherein T₀ is a reference temperature of typically 20 °C and α_α and α_γ are the linear heat expansion coefficients of ferrite and austenite.

EFFECT: determination of the ferrite phase fraction after heating or cooling the steel strip is disclosed.

18 cl, 3 dwg