Research On Deformation Behavior Of X25CrNiSi18-9Stainless Steel Centrifugal Casting Pipe Used In Nuclear Power At Elevated Temperature

This thesis used the X ray diffraction （XRD）,optical microscope （OM）, scanningelectron microscopy （SEM）,transmission electron microscopy （TEM）,electronbackscatter diffraction （EBSD） and energy spectrum analysis （EDS） technology，through the compressive and tensile experiment at elevated temperature,studied thedeformation behavior of X25CrNiSi18-9austenitic stainless steel centrifugal castingpipe used in nuclear power at elevated temperature.The matrix microstructure of X25CrNiSi18-9stainless steel pipe is austenite,precipitates is mainly Cr23C6,a small amount of Cr7C3;near the outer diameter andinner diameter is equiaxed grains, the rest is columnar grain.The results of tensile behavior of X25CrNiSi18-9austenitic stainless steel atelevated temperature,the effects of temperature and strain rate on tensile properties isobvious. The tensile rate increases, the tensile strength is higher and the lower thetemperature, the tensile strength is higher.The tensile fracture type of X25CrNiSi18-9austenitic stainless steel at900℃,1000℃and1100℃is ductile fracture,but at1200℃is brittle fracture.The results of compression behavior of X25CrNiSi18-9austenitic stainless steel atelevated temperature, with the same strain rate,flow stress decreasing with theincrease of deformation temperature;with the same deformation, flow stressincreasing with the increase of strain rate, with the low strain rate and the littleamount of deformation,the dislocation density is low and the grain deformationoccurred; but with the high strain rate and the large amount of deformation,thedislocation density is high and the dynamic recrystallization occurred. Therelationship between the flow stress and the deformation parameters ofX25CrNiSi18-9austenitic stainless steel can be described as the following equation:ε=1.74×10¹¹[sinh（ασ_p）^5.54]exp（-5.31×10⁵|RT）...