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Volume 27 (1989)
- Issue 6 Pages 318-
- Issue 5 Pages 240-
- Issue 4 Pages 182-
- Issue 3 Pages 122-
- Issue 2 Pages 74-
- Issue 1 Pages 3-
Predecessor
Volume 27, Issue 6
Displaying 1-6 of 6 articles from this issue
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Yuji FUKUDA, Seiji KIMURA1989 Volume 27 Issue 6 Pages 318-325
Published: November 25, 1989
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThis paper presents an evaluation methods of corrosion life of fossil-fired boiler tubes based on extreme value (doubly exponential) distribution model. A number of thickness date of boiler tubes obtained by ultrasonic measurement were analyzed using several statistical methods. As the results, the maximum penetration value mostly fits to extreme value distribution. Though scale parameter (α) and location parameter (λ) vary with operational time, position of tubes and boilers, α increases with incresase of λ. In order to improve the accuracy of the analysis, it is necessary to use about 40 data in the case of return period (T) is 5, 000.
According to these results, extreme value statistical analysis was thought to be a very useful method for predicting the maximum value of penetration and the corrosion life of boiler tubes.View full abstractDownload PDF (2203K) -
Akira AOKI, Hiromi KAWAGUCHI, Akira KANEUJI, Masaharu FIJIWARA1989 Volume 27 Issue 6 Pages 326-335
Published: November 25, 1989
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSHigh Pressure Valve with Bellows Stem Seal
The leakage from the valve installed in the nuclear power plant, through which a radioactive fluid flows, is not allowed.
In the valve structure, the actuator and the trim are connected usually with the stem which is sealed in the packing box, where the perfect sealing is impossible because of the sliding motion of the stem.
To privent the radioactive fluid from leaking through the packing box, stems are sealed by the bellows in some valves used in nuclear power plants. The bellows used in a high pressure valve for PWR plant.
Not a few bellows, however, after hundreds of stem reciprocating cycles, have experienced breakage of which cause have been investigated to be low-cycle-fatigue resulting from pressure fluctuation. Development of a bellows having the endurance for low-cycle-fatigue became an essential and urgent requirement.
Some PWR plants are now using the newly developed bellows, which is exbiting satisfactory performance.View full abstractDownload PDF (1669K) -
by Static Tilt Tests Using a Large Model of Exact Similitude (1st Report)Fujikazu SAKAI, Akira ISOE, Hajime HIRAKAWA, Yukio MENTANI1989 Volume 27 Issue 6 Pages 336-346
Published: November 25, 1989
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSIn order to investigate the uplifting behavior of large-scaled LNG, LPG and oil tanks, which has recently been said to be closely related with the earthquake damages, the authors conducted a series of static tilt tests using a very big model made of aluminum alloy with about 10m diameter and 8m height. This model is characteristic of satisfying almost perfectly the similitude to actual large-scaled tanks, and the tilt test made it possible to conduct such big experiments and to measure in detailes the behaviors.
In the experiment, many anchored cases were carried out, the parameters of which are rigidity of anchor strap, magnitude of anchor prestress and so on. The subjects of this paper are to introduce the outline of the static tilt tests and to discuss about the influence of anchor rigidity.View full abstractDownload PDF (2613K) -
Takesuke KOHNO, Norihiko KATAYAMA, Yoshio WAKI, Toyoo KUREHASHI1989 Volume 27 Issue 6 Pages 347-356
Published: November 25, 1989
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSTo improve welding quality and welding efficiency of submerged arc welding, the authors developed HCD (High Current Density) SAW methods using DC of drooping characteristics for horizontal position and AC for flat position with twin wires with high deposition rate and high speed with current density of 100-200A/mm2.
In this study, applicability of the HCD-SAW method to 9% Ni steel was investigated in horizontal and flat position. Effect of current density on deposition rate, workability, arc stability with current density and the properties of the welded joints were investigated with using 70% nickel alloy type welding material of 1.6mm dia. New methods were actually applied to the aboveground LNG storage tanks of 80, 000kl capacity successfully.
Results obtained are as follows;
1) Appropriate current density of the methods was 100-140A/mm2 for horizontal position and 160-180A/mm2 for flat position, which gave the deposition rate of 150-210g /min and 240-290g/min respectively, 1.3-2 times larger than that of the conventional methods.
2) Properties of the welded joints were the same or superior than those of the joints by conventional methods.
3) Welding was done successfully at site and shop, and exellent welding quality was confirmed by radiographic test.View full abstractDownload PDF (5234K) -
Tadami TOMITA1989 Volume 27 Issue 6 Pages 357-373
Published: November 25, 1989
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSNew nondestructive test techniques were developed every year but the evaluation were not clear for actual application, because the judgement of test results depond on mainly experimental data or special case.
This report investigated about existing radiographic, ultrasonic, magnetic and penetrant and visible test of welded joint in various pressure vessels codes and proposed some consideration of the evaluation and availability of nondestructive tests.View full abstractDownload PDF (1939K) -
1989 Volume 27 Issue 6 Pages 374-384
Published: November 25, 1989
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSDownload PDF (1296K)
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