METHOD AND PLANT FOR MANUFACTURING OF HOT-ROLLED STRIP WITH DUPLEX STRUCTURE Russian patent published in 2009 - IPC C21D8/02 B21B45/02 C22C38/04 

FIELD: metallurgy.

SUBSTANCE: method concerns manufacturing method of hot-rolled strip with duplex structure from ferrite and martensite. For receiving of hot-rolled strip (10) with duplex structure from 70-95% of ferrite and 30-5% of martensite, with high mechanical strength and high deformability, tensile strength over 600 MPa and failure elongation at least 25%, strip implemented from steel with chemical composition 0.01-0.08% carbon, 0.9% silicon, 0.5-1.6% manganese, 1.2% aluminium, 0.3-1.2%) chrome, iron is the rest, and also unavoidable admixtures after rolling is cooled in two stages at cooling route of founding - rolling plant, with final rolling temperature T_final at A₃-100K<T_final<A₃-50K till strip winding temperature T_winding<300°C, i.e. lower temperature of martensite transformation beginning, at that speed V_1,2 of cooling at both stages of cooling is V=30-150K/s, mainly V=50-90K/s, at that the first stage of cooling is implemented up to cooling curve approach into ferritic range, and then disengaged in the issue of transformation of austenite into ferrite, transformation heat is used for isothermal heating of reached temperature T_const of strip with time of heating 5s up to beginning of the second stage of cooling.

EFFECT: creating of advantageous manufacturing process of hot-rolled strip with duplex structure from ferrite and martensite.

4 cl, 3 dwg