DiscussiononSafetyDischargeCalculationMethodofSeamlessSteelPressureVesselAbstract:Asforthelargeseamlesssteelpressurevessel,howtoinstallthesafetyreliefdeviceandtocalcu-latethesafetydischarge,itusuallybasedonthespecialmethodandformularequiredinGB150-1998,JB4732-1995andSafetyTechnologySupervisionRegulationofPressureVessel.However,whenthevesselisinfireenvironment,thecalculationmethodofsafetydischargeisn¡¯tdefinite.Sothisarticledescribesanddiscussestheprojectinmoredetails.Keywords:largeseamlesssteelpressurevessel,fireenvironment,safetydischarge,calculationmethod,discussionSelectiononHeatTreatmentTestPlateofParentMaterialandRepeatingHeatTreatmentforHeatingForgingHeadUsedSteelPressureVesselAbstract:HeadusedsteelpressurevesselisrequiredwithparenttestplantandrepeatingheattreatmentafterheatingforginguptoGB150.Itisanimportantproblem.Inthispaper,thisproblemshouldbediscussedaccordingtostandardandprincipleofmetallographyandheattreatment.KeyWords:headusedsteelpressurevessel,heatingforging,parentheattreatmenttestplant,repeatingheattreatmentofparent