上游充通大学 材料科学与工程学院 School of Materials Science and Enginecring.SITU CARBON DIFFUSION Diffusion that driven by aging Mas,F.,et al.(2016)."Metallurgical characterization of coupled carbon diffusion and precipitation in dissimilar steel welds."Journal of Materials Science 51(10):4864-4879. AS-WELDED AFTER PWHT WIT五WHITE Martensite Tempered and carburized Carburized austenite BRIGHT BAND martensite MIXED 18MND5 309 18MND5 309 MICRO STRUCTURE 8h ZONE → TYPE-II 610°c BOUNDARY ELIMINATED 200um 200um HeatⅢ Weld metal-Austenitic matrix with Base metal-Bainitic microstructure residual ferrite
CARBON DIFFUSION Diffusion that driven bygg a in Mas, F., et al. (2016). "Metallurgical characterization of coupled carbon diffusion and precipitation in dissimilar steel welds." Journal of Materials Science 51(10): 4864-4879. WITH WHITE BRIGHT BAND MIXED MICRO STRUCTURE ZONE TYPE-II BOUNDARY ELIMINATED Heat!!!
上游充通大学 材料科学与工程学院 School of Materials Science and Enginecring.SITU MIGRATION OF TYPE-II BOUNDARY Aging lead to more low-angle boundary higher hardness Kim,T.H.,et al.(2015)."Structural assessment of reactor pressure vessel under multi- layered corium formation conditions."Nuclear Engineering and Technology 47(3):351- 361. Heat treatment and aging condition Aging temperature Aging time As As weld As weld weld Y15 1357h ■50m ■50m Y30 450℃ 2750h Y60 5500h THE REGION BETWEEN TYPE-II BOUNDARY AND FUSION BOUNDARY CONTAINS A SERIOUS ELEMENT VARIATION. ■50m 50m
Aging lead to more low-angle boundary & higher hardness MIGRATION OF TYPE-II BOUNDARY g g g yg Kim, T. H., et al. (2015). "Structural assessment of reactor pressure vessel under multilayered corium formation conditions." Nuclear Engineering and Technology 47(3): 351- 361. Aging temperature Aging time As Heat treatment and aging condition weld As weld As weld Y15 450℃ 1357h Y30 2750h Y60 5500h THE REGION BETWEEN TYPE-II BOUNDARY AND FUSION BOUNDARY AND FUSION BOUNDARY CONTAINS A SERIOUS ELEMENT VARIATION
上海充通大学 材料科学与工程学院 School of Materials Science and Enginecring.SITU CONFLICT UNDERSTANDING OF WHITE BRIGHT BAND C-rich zone diluted zone Ming,H.,et al.(2017)."Microstructure of a safe-end dissimilar metal weld joint(SA508- 52-316L)prepared by narrow-gap GTAW."Materials Characterization 123:233-243 182 SA508 175173166 52 6 180172182 180 178172175 MC4TC.7.532e+003 C (b) Fo HIGH HARDNESS BUT 80 SA508 52 LOW C CONTENT LOW NI CR CONTENT HIGH FE CONTENT 1002033040050060070300900100城11091200 200m Distance,um
C-rich zone & diluted zone Ming, H., et al. (2017). "Microstructure of a safe-end dissimilar metal weld joint (SA508- CONFLICT UNDERSTANDING OF WHITE BRIGHT BAND g, , ( ) j ( 52-316L) prepared by narrow-gap GTAW." Materials Characterization 123: 233-243 • HIGH HARDNESS BUT HIGH HARDNESS BUT LOW C CONTENT • LOW NI & CR CONTENT HIGH FE CONTENT
上游充通大学 材料科学与工程学院 School of Materials Science and Enginecring.SITU Background Nickel based alloy used in nuclear power Nickel and Nickel-base Alloys Commercially Solid-Solution Precipitation Specialty Pure Strengthened Strengthened Alloys Ni-Cu Ni-Al-Ti Ni-Al Ni Intermetallics Ni-Mo Ni-Cu-Al-Ti Oxide Ni-Fe Dispersion Solid-solution strengthened Ni-Cr-Al-Ti Strengthened Ni-base alloys NI-Cr-Fe Ni-Cr-Nb Ni-Cr-Mo-W >Higher strength Ni-Fe-Cr-Nb-Al-Ti >Corrosion resistance Ni-Fe-Cr-Mo >Temperatures up to 800 C Ni-Cr-Co-Mo
Background Nickel based alloy used in nuclear power Solid - solution strengthened Higher strength Corrosion resistance Ni - base alloys Corrosion resistance Temperatures up to 800 ℃
上海充通大学 材料科学与工程学院 School of Materials Science and Enginecring.SITU Background Nickel based alloy used in nuclear power Summary of the general effect of various alloying elements on phase stability in Ni-base alloys. Effect Element Solid Solution Strengthener Co,Cr,Fe,Mo,W,Ta Y'-Ni(Al,Ti)Former Al,Ti Solid Solution Strengthening of y' Cr,Mo,Ti,Si,Nb y"-NisNb Former Nb Carbide Formers: MC and M(C,N) W,Ta,Ti,Mo,Nb MC3 Cr M23C6 Cr,Mo,W MC Mo,W TCP Phase (o,P,u,Laves) Ti,V,Zr,Nb,Ta,Al,Si Surface Oxide (Cr2O3/AlO3)Fromer Cr,Al
Background Nickel based alloy used in nuclear power Summary of the general effect of various alloying elements on phase stability in Ni - base alloys