Research On Hot Deformation Behaviors,Microstructures And Properties Of F45MnVS Steel

In recent years,our country attaches great importance to the research and application of non-quenched and tempered steel,but in domestic,for the production of F + P type high strength,high toughness of non-quenched and tempered steel,research and application were fewer,it is necessary for the further detailed research work on it.Based on the requirement of F45 MnVS non quenched and tempered high strength steel production of the Nanjing steel,from the hot rolling process,chemical composition,the improve of strength and toughness,for the dynamic CCT curve of F45 MnVS non-quenched and tempered steel,microstructure,the conventional mechanical properties,dynamic recrystallization behavior,the heat treatment Orthogonal experiment on the steel,compared with the property of non-quenched and no-tempered steel,and F45 MnVS steel's finished rolling mechanics property calculation carried out focus research.The main content of the paper are as follows:1.Using Gleeble-2000 proceed dynamic CCT experiments on F45 MnVS steel,determined F45 MnVS steel's austenitic phase transformation temperatures,AC1=720 ?,AC3 = 774 ?;F45MnVS steel's dynamic CCT curves,there are mainly three kinds of organization transformation:(1)When the cooling rate is low,the cooling rate is 0.1 ?/s ~ 5?/s,ferrite+pearlite transformation is mainly occurred;(2)When the cooling rate is high,the cooling rate is 7?/s~10?/s,it can be seen in the organization of feathery bainite organization,bainite transformation is mainly occured;(3)When the cooling rate is 12?/s or above,you can see of the plate strips martensite,martensitic transformation is occurred.2.Using Gleeble-2000 proceed single channel compression experiment on F45 MnVS steel.According to the data from experiment,draw out the stress-strain curve of F45 MnVS steel in different hot deformation conditions,analyzed the relationship among deformation conditions and deformation resistance and recrystallization;Calculated out recrystallization activation of the steel is 418.583KJ/mol.Given the deformation resistance formula and deformation constitutive equation of F45 MnVS steel's hot deformation.3.F45 MnVS steel's microstructure is ferrite + pearlite,used in the manufacture of automobile shaft parts,it's strength was high enough but it's toughness was not enough.This article through F45 MnVS steel's quenched and tempered treatment experiments,compared with non-quenched and tempered steel's properties.Come to the conclusion: the optimal process of orthogonal experimental design for F45 MnVSsteel is heated to 800 ?,insulation 20 min,with water as medium,quenching,Then the experimental steel heated to 600 ?,insulation 60 min,move out and air cooling.After the Quenched and tempered treatment,F45 MnVS steel obtain tiny tempered sorbite structure,toughness is best,the highest impact energy value AKu reached to 155 J.4.Used the electronic structure calculation method,according to the chemical composition of F45 MnVS steel,the austenitic grain size of finished rolling,combined with non-quenched and tempered steel rolling process of solid solution strengthening,fine-grain strengthening,dispersion strengthening,precipitation strengthening,pearlite transformation,calculated out F45 MnVS steel's finished rolling mechanical properties,the value of ?b is 901.65 MPa,the value of ? is 14.75%,the value of AKu is53.58 J,it have a good agreement with the experimental results.