Hasegawa, Naruo; *; Kano, Shigeki; Nakayama, Koichi; Nakasuji, Takashi; Koakutsu, Toru
PNC TN941 80-127, 124 Pages, 1980/08
It is an important subject to clarify the tribological behaviors of structural materials applied for contacting and/or sliding parts of "MONJU" components and take a measure to meet the design condition. From this point of view, a series of parameter tests are conducted on stellite No.6, Colmonoy No.5, Inconel 718 and LC-1C selected by the screening tests, and SUS 316, SUS 304 and 2.25Cr-1Mo steel as main structural materials for "MONJU". Among parameters, the effect of oxygen content in sodium on tribological behaviors is one of disputed points. As the cold trap temperature of "MONJU" primary system is intended to decrease from 140C (or 145C) to 120C, the authors started the tests whose parameter is cold trap temperature. This report describes the test results obtained partially. The test items and test conditions are as follows: I. Corrosion Test Sodium temperature : 600C, Exposure time : 2,000 hr. Cold trap temperature : 120C II. Friction Test Sodium temperature : 600C, Exposure time : 2,000 hr., Contact stress : 0.3kg/mm. Cold trap temperature : 120C III. Self-Welding Test Sodium temperature : 450 700C, Dwell time : 200 hr., Contact stress : 4 kg/mm , cold trap temperature : 120 C Comparison of as-received material with pre-exposed material. Estimation of self-weldability by tension breakaway. Main results obtained are as follows: I. Corrosion Test (1)Corrosion behavior did not indicate apparent difference between cold trap temperature of 120C and 140C. (2)Stellite No.6 showed an increase in weight and other materials tested showed a reduction in weight. II. Friction Test (Stellite No.6/itself and LC-1C/itself) (1)Kinetic friction coefficients did not show apparent difference between cold trap temperature of 120C and 140C. (2)Kinetic friction coefficients did not depend on sodium exposure time. III. ...
Kano, Shigeki; Hasegawa, Naruo; Nakayama, Koichi; Koakutsu, Toru; *; Nakasuji, Takashi
PNC TN941 79-144, 47 Pages, 1979/08
It is requested to obtain the self-welding characteristics in sodium on the contacting materials of "MONJU" components. By tension breakaway method, the tests were up to date conducted on many kinds of materials in sodium which was not cold-trapped and was purified by the cold trap temperature of 190C or 145C. These results were used for material screening. The present study relates to the dwell temperature dependence of 200 hrs. self-welding characteristics on the selected hard facing materials and main structural materials of "MONJU" in 450 700C sodium purified by the cold trap temperature of 140C or 145C. The main results obtained are as follows. (1)The breakaway stress shows the apparent dwell temperature dependence. (2)The combinations of SUS 304/itself and SUS 316/itself self-weld above 500C and the breakaway stress increases linearly with the dwell temperature. (3)Ferritic steels exhibit the higher breakaway stress than austenitic stainless steels. (4)The combination of LC-1C/itself does not easily self-weld even at 700C. The combinations of Stellite No.6/itself, Colmonoy No.5/itself and Inconel 718/itself self-weld at 700C and do not self-weld at 600C. Only Colmonov No.5 breakaways at the inside as well as the self-welded interface. (5)Only Colmonoy No.5 shows the apparent corroded surface among the test materials after exposure to 700C sodium for 200 hrs. LC-1C exhibits flaking partially from the substratum. It is because the coating layer (0.2 mm thick) was too thick and there were the problems of the grid blast method on substratum surface and the manufacturing method on coating edge.
Koakutsu, Toru; Kano, Shigeki; Hasegawa, Naruo; *; Nakayama, Koichi; Nakasuji, Takashi
PNC TN941 79-105, 39 Pages, 1979/07
In view of anti-self-welding and low friction, hard facing materials are applied to the sliding parts of "MONJU" components. But it is thought that the self-welding and friction behavior of these materials is affected by sodium corrosion during long-term application at high temperature. At present report, a friction test was conducted in sodium to investigate the effect of the exposure time in flowing sodium on friction coefficient. This report describes the friction test results for Stellite No.6, Colmonoy No.5, Inconel 718, LC-1C (chromium carbide/nichrome binder) and SUS 316 under the following test conditions : the test temperature of 600C, the cold trap temperature of 140C, the test duration of 2000 hrs., the sodium velocity of 0.7 m/sec, the contact stress of 0.3 Kg/mm, the sliding stroke of 5 mm and the sliding velocity of O 0.63 mm/sec, The results obtained are as follows. (1)All of test materials except for Colmonoy No.5 did not show the exposure time dependency of kinetic friction coefficient (), (2)Degraded layer was appatently observed on the surface of Colmonoy No.5. (3)The coating method must be improved for LC-1C, because the LC-1C of 0.2 mm thick showed edge chipping. (4)The values were as follows. [Stellite No.6/self : 0.15 0.35] [Colmonoy No.5/self : 0.15 1.5] [Inconel 718/self : 0.65 1.15] [LC-1C/self : 0.35 0.55] [SUS 316/self : 1.0 1.2]
Hasegawa, Naruo; Kano, Shigeki; Nakayama, Koichi; Koakutsu, Toru; *; Nakasuji, Takashi
PNC TN941 79-26, 44 Pages, 1979/04
Friction, wear and self-welding resistant materials are applied for many contact and/or sliding parts in FBR components. The pad material of a fuel assembly wrapper tube is a ypical example. Wrapper tube pads of "MONJU" size were trially manufactured with four kinds of hard facing material selected by up to date R&D tests ((1)Stellite No.6 (2)Colmonoy No.6, (3)LC-1C (Chromium Carbide), (4)Inconel 718). In this study, these pads were exposed to 600C sodium for 2,000 hrs.. The following results were obtained. (1)The dimension between the inside of wrapper tube and the pad surface partially changed max. 200m due to the heating during sodium exposure. (2)Stellite No.6: After exposure, the surface showed general corrosion and selective corrosion at the grain boundary. The hardness slightly decreased to Hv 600 and surface roughness slightly increased. (3)Colmonoy No.6: After exposure, the surface showed severe general corrosion, then the depletion of boron and silicon and the degraded layer were observed in the vicinity of the exposed surface. The hardness of this layer significantly decreased to Hv 300 and the surface roughness slightly in creased. (4)LC-1C: After exposure, the surface showed slight general corrosion but cross-sectional micrograph was stable. The hardness increased to Hv 1,100 and the surface roughness slightly increased. (5)Inconel 718 : After exposure, the surface corrosion was slight, but titanium, niobium and molybdenum were depleted in the vicinity of the expoded surface. The hardness and surface roughness did not change before and after exposure.
Hasegawa, Naruo; Kano, Shigeki; Nakayama, Koichi; Koakutsu, Toru; *; Nakasuji, Takashi
PNC TN941 78-100, 48 Pages, 1978/01
A series of experiments in sodium and argon environments have been carried out to develop and screen the friction and wear resistant materials used for sliding components of the sodium cooled reactor. As results of these test, we selected out several materials for candidated alloys. The present study was carried out about combination of Stellite No.6/Self, Colmonoy No.5/Self, Inconel 718/Self and Stellite No.6/SUS304 and long term sliding test (150 hrs.). The results obtained were compared with those of short term sliding test (15 min.) of preceding studies. The results obtained are as follows, (1)Kinetic friction coefficients () of Stellite No.6/Self and Colmonoy No.5/Self were in approximate agreement with short term test of proceding studies (: 0.20.4) (2) of Inconel 718/self showed a stable behavior with the sliding time although it raised at the begining of the test. (3) of Stellite No.6/SUS 304 indicated a variable behavior at the begining of the test, but after 40 hours sliding, it showed a stable behavior with the lapse of time and was about 0.60.7. (4)The Wear depth of Stellite No.6/Self and Colmonoy No.5/Self did not shift for the sliding time. (5)wear depth of Inconel 718 was 2 to 3 times greater than that of Stellite No.6 and Colmonoy No.5. (6)Stellite No.6/SUS304 combination showed the greatest wear depth of all material combinations tested.
Kano, Shigeki; Koakutsu, Toru; Hasegawa, Naruo; Nakayama, Koichi; Nakasuji, Takashi; Atsumo, Hideo
PNC TN941 77-111, 95 Pages, 1977/06
A corrosion test of hard facing material has been conducted in 600C sodium for 2000 hrs. Test pieces were Co base alloys, Ni base alloys and carbides which were provided for tribology studies in sodium. These materials were compared with SUS304, SUS316 and another corrosion and heat resisting alloys by simultaneous exposure. Analysis methods after exposure were as follows: surface roughness, hardness, corrosion rate, surface morphology and metallurgical structure which have influence on friction and self-welding behavior. The results obtained are as follows: (1)Stellitew alloys: Part of test pieces showed weight gain. Change of surface roughness was minute. Structural change was not observed in the surface vicinity of sodium contact. However, hardness increase was observed. (2)Ni base hard facing materials such as Colmonoy alloys: Corrosion rates were high and hardness was reduced. A degraded layer of 10m through 40m was observed on the surface of Colmonoy alloys and their surface roughness increased. (3)Inconel alloys: Corrosion rates were double those of stainless steels. A degraded layer of 1m through 4m was observed on the surface. Change in surface roughness was minute. (4)Corrosion and heat resisting alloys: Corrosion rates showed one to two times greater than those of stainless steels. Change in surface roughness was minute. No change in surface layer was observed. However, precipitates were observed in the metallurgical structures of some alloy types. (5)Carbides: Large increase of surface roughness was observed. LC-1C exhibited stripping from substratum. LW-1N40 indicated wide variation in corrosion rates. (6)Other materials: SUS316 produced a sigma phase at the grain boundary of sodium surface contact.
Kano, Shigeki; Nakayama, Koichi; Hasegawa, Naruo; Koakutsu, Toru; Namekawa, Masaru; Nakasuji, Takashi; Atsumo, Hideo
PNC TN941 77-179TR, 48 Pages, 1977/01
Kano, Shigeki; Nakayama, Koichi; Hasegawa, Naruo; Koakutsu, Toru; Nakasuji, Takashi; Namekawa, Masaru; Atsumo, Hideo
PNC TN941 77-179, 48 Pages, 1977/01
A series of experiments have been carried out to develop and screen friction and wear resistant materials used for sliding components of a sodium cooled reactor. Preceding studies clarified the short-term friction and wear characteristics of various materials in 450C sodium. A present study relates to clarify friction and wear behavior in argon environment, where a part of sliding components are located, and compare test data in room temperature argon with those in 450do sodium. The results obtained are as follows: (1)Static friction coefficients (s) in argon were almost lower than 0.2. They were apt to be lower than those in sodium. (2)Kinetic friction coefficients (k) in argon varied with load. The difference of k in argon and sodium depended on material combination. (3)Wear rates were remarkably high in argon. Wear rates of Colmonoy and Stellite were not detected in sodium, but were detected in argon. (4)Sliding surface was more roughened in argon, and hardness of sliding surface was almost lower in argon than in sodium. (5)There is the significant difference between friction and wear characteristics argon and those in sodium. Then, it is difficult that in-sodium behavior is estimated with in-argon data. (6)The above-mentioned difference in room temperature argon and 450C sodium will be greater when the test is carried out in higher temperature argon.
Kano, Shigeki; *; Nakayama, Koichi; Hasegawa, Naruo; Koakutsu, Toru; Atsumo, Hideo; Nakasuji, Takashi
PNC TN941 76-81, 25 Pages, 1976/07
A series of experiments in sodium environment have been carried out to develop and screen the friction and wear resistant materials used for sliding components of the sodium cooled reactor. The present study relates to the friction and wear characteristics of nickel-basealloy "Colmonoy" and cobalt-base alloy "Stellite" with respect to temperature, load, sliding velocity, sliding mode and sodium flushing. Also several experiments were carried out in argon and atmospheric environments, and they were compared with those in sodium. The results obtained were as follows : (1)As the sodium temperature is raised, the kinetic friction coefficient () of Stellite alloy becomes higher, but that of colmonoy alloy remains constant or is rather lower. The of Collmonoy alloy becomes lower by 540C sodium flushing. (2)Both static friction coefficient () and of Colmonoy alloy are lower than those of Stellite alloy in sodium environment. (3)The dependence of and upon the load is low in sodium environment. In argon the dependence of upon the load is not found, while varies according to the load. (4)The friction behavior is influenced by sliding mode. The in oscillating sliding is higher than that in one-directional continuous sliding. Also the sliding surface in oscillating sliding is more roughened. (5)The dependence of upon the sliding velocity is not found in sodium environment except for that in low velocity area. (6)The kinetic friction coefficient is apt to be higher in argon than in sodium. Also the wear rate is much higher in argon.