METHOD FOR TEMPERATURE CYCLING OF MULTIPHASE STRAINED IRON-BASED ALLOYS Russian patent published in 2004 - IPC

FIELD: iron metallurgy, in particular heat treatment of multiphase strained iron-based alloys, preferably hypereutectic steel and cast iron.

SUBSTANCE: method comprises multiple heating to temperature lower by 50-150⁰C than that of alloy solidus, soaking, and cooling. Cycle number (n) is selected according to equation: n = C(total) - 0.8/B x kΔT, in which C(total) is total carbon content in alloy, %; 0.8 is carbon content in eutectoid; k = (1-3)x10^-3%C/⁰C and represents solubility coefficient (i.e. changing of carbon content in austenite when temperature changes by 1⁰C); ΔT is temperature cycling range higher than A₁(ΔT = T_k-A01),

C (T_{k =} T_solidus - (50-150)⁰C and represents the highest cycle temperature; A₁ - alloy eutectic temperature, ⁰C); B = 0.3-0.5 and represents content of dissolved coarse carbides. In preferred embodiment of invention n = 2-10; multiple heating and cooling are interrupted by isothermal soaking at highest cycle temperature; and final cooling is carried out in air, liquid or gas medium.

EFFECT: alloys with improved mechanic properties due to homogeneously distributed exceed phase.

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