| 摘要 |
PURPOSE:To obtain an accurate measurement result by cutting a steel pipe into a ring of specific width, providing a narrow part to be tested to part of the ring and obtaining a test-piece, and making semicircular jigs which face each other abut on the inside of the ring and spreading them outward by a hydraulic jack provided between the jigs. CONSTITUTION:The steel pipe as an object of tension test is sliced to specific width and the narrow part 2 to be tested whose border part is made gentle so as to evade stress convergence on part of the obtained ring-shaped steel pipe is formed. An upper semicircular jig 4 which has a little bit smaller diameter and operates on the part 2 to be tested as an internal pressure applying jig 3 is made to abut on the inside of the test-piece 1 across a frictional force reducing material 7 such as a 'Teflon(R)' sheet and a similar lower jig 5 is arranged at an internal. Then the hydraulic jack 6 provided between the jigs 4 and 5 is operated to load the jigs 4 and 5 outward, thereby applying a tensile force to the part 2 to be tested. Consequently, the accurate measurement result is obtained without causing Bauschinger effect, working setting, etc., to appear on the test-piece 2.
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