Research on development of high-purity iron-based alloys; Manufacture, analysis of small amount of element and property tests

; *; ; ; Aoto, Kazumi;

JNC TN9400 2000-059, 43 Pages, 2000/05

JNC-TN9400-2000-059.pdf:2.08MB

The purpose of this study is to understand the material properties of manufacturable high-purity iron and high-purity iron-based alloy in present technology and to get an applicable prospect for the structural and functional material of the frontier fast reactor. Then the about 10kg high-purity iron and iron-based alloy were melted using a cold-crucible induction melting furnace under the ultra-high vacuum. Subsequent to that, the compatibility between the melted material and the high-temperature sodium environment which is a special feature of the fast reactor and tensile property at room and elevated temperatures were investigated using the melted materials. Also, the creep test using the high-purity 50%Cr-Fe alloy at 550C in air in order to understand the high temperature creep property. ln addition, the material properties such as thermal expansion coefficient, specific heat and electrical resistance were measured and to evaluate the outlook for the structural material for the fast reactor. The following results were obtained based on the property test and evaluation. (1)lt was possible to melt the about 10kg high-purity ingot and high-purity 50%Cr-Fe alloy ingot using a cold-crucible induction melting furnace under the ultra-high vacuum. (2)The tensile tests of the high-purity 50%Cr-Fe alloy were performed at room and elevated temperatures in order to understand the deformation behavior. From the experimental results, it was clear that the high-purity 50%Cr-Fe alloy possesses high strength and good ductility at elevated temperatures. (3)The physical properties (the thermal expansion coefficient and specific heat etc.) were measured using the high-purity 50%Cr-Fe alloy. lt was clear that the thermal expansion coefficient of high-purity 50%Cr-Fe alloy was smaller than that of SUS304. (4)From the corrosion test in liquid sodium, the ordinary-purity iron showed the weight loss after corrosion test. However the high-purity iron showed ...

Microstructural assessment of damaged materials in FBR assessment of creep damage in weldment

Momma, Yoshio*; *; ; ; ; Aoto, Kazumi

JNC TN9400 2000-044, 22 Pages, 2000/03

JNC-TN9400-2000-044.pdf:1.37MB

ln the past the microstructural observation was mostly applied to understand the materials behavior qualitatively in R&D of the new materials and the life prediction for the fast breeder reactor components. However, the correlation between the changes in properties and microstrutures must be clarified to ensure the structural integrity. Particularly we are interested in the method to correlate the long-term properties and microstructural changes at high temperatures. The current research is to quantify the changes in microstructure of the weld metal for the welded structure of the reactor vessel. ln this research we have conducted creep testing of the weld metals at 823 and 873K up to 37,000h. Two types of the weld metals (16Cr-8Ni-2Mo and 18Cr-12Ni-Mo) were subjected to the creep testing. Based on the areas of the precipitates, the microstructural characterization with time and creep damage was attempted. The creep strength of the 16Cr-8Ni-2Mo weld metal is lower than that of the 18Cr-12Ni-Mo one at higher stresses, shorter times. But there is a trend toward to become similar strength with lower stresses and increasing times. The creep-rupture ductility of the 16Cr-8Ni-2Mo weld metal is superior to that of the 18Cr-12Ni-Mo one. The creep-rupture takes place at the interface of the sigma () phases precipitated in the delta () ferrites at 823K lower stresses and 873K. The amount of precipitates in the 16Cr-8Ni-2Mo weld metal is smaller than that in the 18Cr-12Ni-Mo one at each temperature and stress. Also it is apparent that the amount of the precipitates is primarily responsible to the decomposition of the phase, because the amount of the residual ferrites measured by the Magne-Gauge reduces with times. Using the Larson-Miller parameter it was possible to correlate the amount of the precipitates linearly with the LMP values.

Materials properties data sheet (No.Q 01); Internal pressure creep properties data on high strength ferritic/martensitic steel in air and in sodim

; ; *; *; Yoshida, Eiichi;

PNC TN9450 92-004, 37 Pages, 1992/06

PNC-TN9450-92-004.pdf:0.78MB

High Strength Ferritic/Martensitic Steel is one of the cardidate core materials for largescale FBR because of excellent resistance to swelling. This report are presented about the internal pressure creep of High Strength Ferritic/Martensitic Steel based on the R&D results obtained through the activities of material tests. Contents of the data sheet are as follows; (1) Material: High Strength Ferritic/Martensitic Steel Fuel cladding tube (6.50.47.mm) (2) Environment: In Air and In Sodium (3) Test temperature: 600 and 650C (4) Hoop stress: 9.4832.43 kgf/㎜ (5) Number of data: 13 points

Material properties of weld joints of reduced activation ferritic/martensitic steel, F82H

Hirose, Takanori; Sakasegawa, Hideo; Nakajima, Motoki; Tanigawa, Hiroyasu

no journal, , 

Weld joints of a reduced activation ferritic/martensitic steel, F82H were prepared using Tungsten-Inert-Gas (TIG) and Electron Beam (EB) welding. Physical properties and mechanical properties of these weld joints were investigated in this work. Moreover, effects of Post Weld Heat Treatment (PWHT) was also investigated. After PWHT at 720 C, most of physical properties of weld metal were very similar to those of F82H base metal. Coefficient of thermal expansion and thermal diffusivity of weld metal demonstrated 10% of degradation compared to the base metal. Although weld metal and heat affected zone heated above transformation temperature demonstrated hardening and embrittlement, PWHT above 750 C successfully moderated the hardening without softening in the base metal.