Thepipelinesteelisusuallyproducedbyaddingniobiumandvanadiumalloyingelements.Thetitaniumalloyedpipelinesteelwasstudiedinthepapertoreducetheproductioncostandenhancethecompetitiveabilityofpipelinesteel.Thesteelcontaining0.070%Tiwasrefinedinthelaboratoryvacuumrefinefurnace.ThedynamicCCTcurveofdevelopedsteelwasconductedonGleeble-1500thermalsimulatorandmulti-passdeformationtestsofstudiedpipelinesteelwereperformedtosimulatetheCSPhot-rollingtechnology.Correspondingmicrostructureswereobservedandtheinfluencesofsuchtechnologyparametersasdeformationstrain,deformationtemperature,coolingrateandfinishingtemperatureetc.onmicrostructurewereanalyzed.ThedynamicCCTcurvewasobtained.ThetestresultsshowedthatthevolumefractionofacicularferriteinthemicrostructureofTi-microalloyedX70pipelinesteelincreasedobviouslywiththeincreaseofcoolingrateafterthermo-mechanicaldeformation.However,thevolumefractionofacicularferritevariesscarcelyafterthecoolingrateof20℃/s.InordertoobtainTi-microalloyedX70pipelinesteelwithexcellentcompoundmechanicalpropertieswhichhasacicularferriteasthemainidealmicrostructure,thecoolingrateshouldbecontrolledtobe20℃/sormore.Thehigherofthefinishingtemperature,themoreofthevolumeofacicularferriteandthelessofthevolumeofpolygonalferrite.Thequitefinemicrostructurecanbeobtainedbyloweringthefinish-coolingtemperature.TheresultshaveshownthatitispossibletoproducetheTi-additionX70pipelinesteelfromthepointofviewofmicrostructure.
