PROCEDURE FOR THERMAL ANTI-FLOCCULANT TREATMENT OF FORGED PIECES Russian patent published in 2010 - IPC C21D3/06 

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy, particularly to process of thermal anti-flocculant treatment of big-size items including forged pieces out of carbon and alloyed steel Considering specific chemical composition of steel, degree of its alloying and to optimise duration of thermal treatment, forged pieces are cooled upon forging in air to 250-350°C, then heated in furnace to 660-700°C, conditioned for a time depending on diametre of piece and on source contents of hydrogen in metal and cooled at rate 5-20°C/h to temperature 240-260°C. Also forged pieces are conditioned depending on steel alloying. Additionally, time of conditioning is determined from the equation: τ=0.186·K·R²/D_H·ln[1.596·C⁰ _H/C^f _H], where: -C⁰ _H, C^f _H is beginning and final concentration of carbon in forged pieces metal, %, R is radius of forged pieces, cm, K is ratio considering position of flocculants along cross section of forged pieces: for medium and high alloyed steel K=1, for carbon and low alloyed steel K=2/3, D_H is coefficient of hydrogen diffusion in a forged piece, cm²/h, determined: , C_i - is concentration of carbon and alloying elements, wt %, µ_I λ_i - are parametres for calculation of alloying elements influence on coefficient of hydrogen diffusion, T - temperature of a forged piece, °C, n- amount of steel components.

EFFECT: increased efficiency of thermal anti-flocculant treatment.

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