Study On Regularities Of Reciystallization And Phase Transformation In High Quality Alloyed Tool Steel SKS51

High quality alloy tool steel is widely used in the engineering machinery, metal products,auto manufacture, aerospace, large-scale special equipment and special apparatus,etc. Thecircular diamond blade, one of the main tools for cutting natural rock and section technology, isone of its typical application fields. In the world, only a few enterprises in Germany, Japan andKorea are able to produce this kind of product, but the domestic like product can not meet themarket requirements. Aiming at a domestic steel company for achieving the industrializationand scale production of the high quality alloy tool steel SKS51, the hot deformation behavior,dynamic and static recrystallization and phase transition law of SKS51have been studiedthrough thermal simulation technology.The main researching contents and conclusions:(1) The true strain–true stress curves of different deformation technological conditionswere acquired through single compression deformation experiment and the flow stress modelwas built subsequently. Using JMA equation, the dynamic recrystallization volume fraction wascalculated and also the calculating model was built. The microstructures for differentdeformation processes were analyzed through metallographic microscope and scanning electronmicroscope, and primary discussions on deformation induced pearlite transformation weremade.(2) Double-pass compression deformation experiments have been carried out to study thestatic recrystallization behavior. Using stress compensation method, the static recrystallizationvolume fractions of different deformation technological conditions with various holding timewere determined, and the static recrystallization dynamic equations was built.(3) The dynamic CCT curve was built and then the phase transformation temperatures fordifferent cooling rate after hot deformation and its impacts on microstructure have beendetermined. And finally, the influences of finishing rolling temperature on phase transformationand steel hardness were analyzed.This research will provide the theoretical foundation to set TMCP parameters, optimizerolling process, form complete set of manufacturing technology of producing high quality alloytool steel as soon as possible and realize industrialization and scale production.