| 摘要 |
PURPOSE:To improve pressure proof performance of a hollow structure by giving temp. difference between both surfaces in thickness direction within the range, which does not exceed the yield stress, to the metal-made hollow structure an applying the pressure. CONSTITUTION:A thick wall piping 1 is fixed with clamp 7 and both ends thereof are sealed with plugs 2, and water cooled in a cooler 3 at an arbitrary temp. is circulated into the piping 1 by driving a compressor 5 and circulating pump 6 to cool the inside thereof. On the other hand, the high frequency current is conducted to a high frequency generating coil 9 arranged to outside of the piping 1 from a high frequency generator 10 to heat the outside of piping 1, and the coil 9 is shifted in longitudinal direction of the piping with a control panel 13 through a slider 11 at the fixed velocity. Therefore, tensile stress on inner face of the piping 1 and compressive stress on outer face thereof are developed, and the temp. difference is given to the thickness direction of piping 1 within the range, which does not exceed the yield stress. By this method, the pressure proof performance of the hollow structure is effectively improved. |
