Contribution Of Cast Structure And Mode Of Texturing On Carbide Pattern Of High-Speed Steel

Thathigh-speedtoolsteel (shortforhigh-speedsteel),isledeburitesteelwithhigh-carbonhighalloycontaining large amount of primary carbide , whose quantity , type , distribution , dimension and form hasgreat influence on its Mechanical property . Cast stucture and mode of texturing is the major factor onhigh-speed steeleutectic carbide pattern (evennessdegree andgraininessofeutectic carbide).The velocityofelectroslag remelting is one of impact on cast stucture . The mode of texturing includes the cogging-downtemperature , heats fire forging and stamping a ratio time,the forging hammer forges cogging-down methodwaiting . Therefore , the main body of this thesis takes a research in the influence of the velocity ofelectroslag remelting and the mode of texturing on high-speed steel eutectic carbide pattern . At the sametime,thetechnologicalprocessisoptimumdesigned.Theexperimentresultshows:The velocity of electroslag remelting has slight influence on high-speed steel eutectic carbide pattern .therefore,velocityofelectroslagremelting canbeproperlyinceasedinordertoimprovethe efficiencyoftheremeltinginsteelmakingworkingprocedure,reduceenergyconsumption,andreducethecost.The cogging-down temperature , warmup fire have great influence on eutectic carbide pattern ofhigh-speed steel . for the M2 steel ingot , the most appropriate heats temperature is 1160℃and the superiorlimitcanreach1180℃.Carbidegrainmayaggregateandgrowsupwiththeheatfrequencyincreasing .Withregard to small steel ingot , quick forge machine can be used in cogging-down and cogging-down heats firemayfalloffrelatively.With regard tobig steelingots , accurate forge machine ,whose advangtageisthattheproductcanbegainedafteronceheat,canbeadoptininitial cogging-down,andthen,quickforgesmachinewith fine performance in the following cogging-down .In this method , eutectic carbide pattern can beimmproved.The effect of forge ratio and forge switching is great to high-speed steel eutectic carbide , too . Thesmaller cast eutectic grain is and the larger forge is , the better breaking level is and the lower degree ofcarbid is . Eutectic structure of small ingot is trivial according lower forge ratio . In the other side , for thelarger steel ingot , eutectic grain will be grow larger and non-shattering with forge ratio augmenting . Therank of carbid can be effective improved though controlling the interdependence of the two paradoxicalaspects . When modifying forge ,with enough large forge ratio , the reticulate eutectic can be broken and thecarbidcanberefinedanddistributedhomogeneous.Different forging hammer cogging-down way will lead to different evenness degree and graininess ofeutectic carbide . For the quick forge machine cogging-down , the carbid unevenness is lower than it gainedby accurate forging machine . But , in transverse section , the distribution of carbid gained by accurateforgingmachineisbetter.Furthermore,accurateforgingmachinecogging-down′carbid is more trivialthanthequickforgemachine′. Optimized technological process as following : Steel ingot annealing→heat by ring furnace→cogging-down by SX55 forges machine accurate (cogging-down adopt the subsquence that is circularity–four corners-flat- four corners–circularity)→forge by heating (the middle base)→coal-fired furnacewarmup→forge base produced with 2 T electricities liquid power hammer→anneal→final finishin→rolling mill handing→phase transition anneal→final finishin→dectection . The high-speed steel eutecticcarbidepatternhasarathergreatimprovement.