TREATMENT METHOD FOR INVAR ALLOY BASED ON IRON-NICKEL SYSTEM Russian patent published in 2017 - IPC C21D6/00 C21D1/26 C22F1/18 

FIELD: metallurgy.

SUBSTANCE: method involves heating to 830-850 °C, cooling in water, additional cooling to a temperature below starting point of γ→α transformation, heating to the starting point of reverse α→γ transformation, further heating to the end point of α→γ transformation, followed by heating at a rate of 10 °C/minute or higher to a temperature exceeding the end point of α→γ transformation by 10÷100 °C, and cooling in the air. Further heating in the α→γ transformation range is performed at a rate of 0.2÷3 °C/minute. After air cooling, additional heating within 500-700 °C range and isothermal ageing for 15 minutes to 10 hours are performed, followed by air cooling.

EFFECT: reduced temperature of the start of martensitic transformation of Mn alloys and extended temperature range.

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