| 摘要 |
PURPOSE:To greatly shorten the time of a check test of heat resistance by using a test-piece which has a hole in its top surface so that the angle of the edge part of the hole is <=60 deg., and heating and cooling the test-piece rapidly and generating large thermal stress. CONSTITUTION:The test-piece 1 has the hole 2 in the top surface and the angle of the edge part of this hole 2 is <=60 deg.. At the time of heat-resistance check measurement, the test-piece 1 is fixed in the recessed part 6 of a mount base 5 by a screw member 7 and then four thermocouples 11 are fitted to the test- piece 1. Then, a high frequency coil 8 is installed above the test-piece 1. Then while the mount base 5 is rotated by a driving device at 500 r.p.m., the edge part 3 of the test-piece 1 is heated rapidly at 200 deg.C/sec up to specific temperature and then cooled forcibly with a blast or water from above. Consequently, large thermal stress is generated in the test-piece 1 and this operation is repeated several tens of times to cause the edge part 3 of the test-piece 1 to crack. The temperature difference generated at the periphery of the cracking is measured by the thermocouples 11 and the number of times of repetition up to the generation of the cracking is measured.
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