In-Sodium tests of hard facing materials (VII); Corrosioh, friction and self-welding test results at cold trap temperature of 120C

Hasegawa, Naruo; not registered; Kano, Shigeki; Nakayama, Koichi; Nakasuji, Takashi; Koakutsu, Toru

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. ...