Scanning Electricity Mirror and the Electron Probe Microanalysis are used to analyze the organization change and the alloying element distribution of 12Cr1MoV steel.As operation time increases

the crystal grain has the coarsening and the quantity of carbide precipitation also increases.The chromium element separated from carbide is very serious.After 5×10

4

h operation

the chromium element separated from carbide is already obviously seen in crystal boundary.Moreover the degree of precipitation seems to be more obviously as time goes by and precipitation is seen in crystal

too.The molybdenum element also has precipitation in carbide

though not obviously.Precipitation occurs after operation 10×10

4

h.The vanadium element is quite stable.The alloying element content change occurs mostly in pearlite and carbide.In ferrite organization

the content of each kind of alloying element ma

intains the same.