Through means like optical microscope

transmissive electronmicroscope

and X-ray diffraction meter etc.

the microstructure of boiler tube samples made from stabilized stainless steel in different servicing periods has been tested and studied.Results show that the slipline

twin crystals

and layer slippage are gradually eliminated along with the lengthening of servicing time in the servicing process

the density of location slippage being pradually reduced

the lines of location slippage tend to straighten;the quantity of second-phase in crystals has slightly increased

and basically unchanged thereafter

the particle size has slightly increased

the quantity of second-phase in boundary of crystals gradually increases

the size also gradually increases;compared with the evolving regularity of microstructure on boiler tube made from non-stainless steel

the most significant difference is that the variation of carbide in crystals and the composition ratio in separated out phase are different.