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Article type: Cover
Pages
Cover1-
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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Article type: Cover
Pages
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Published: June 30, 1970
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Jiro OKAMOTO, Mamoru HIROSE, Katsuji MIYAMOTO, Hiroshi KURODA
Article type: Article
Pages
1-10
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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Although labor save and automation of works have remarkably been proceeded in hull construction works, there remain still much manual works and proportion of human factor is large. So reliability of hull constructions must due to workers reliability as well as those inspection. Therefore total quality control based on human respect and mutual reliance is necessary in hull construction works in addition to statistical quality control. This paper describes successful examples of quality control in a shipyard by means of a quality assurance system in conjunction with an individual of workers, estimation and expression of individual ability, self-inspection, education for enlightment of individual will and ability, etc.
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Hideo TAKEDA, Tomoyoshi KUROI, Naoshi TOYOSHIMA, Josuke YAMAGUCHI
Article type: Article
Pages
11-21
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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As one of the applications of high frequency induction heating to ship outfittig work, a new pipe bending method for reducing the pipe fabrication process by elimating elbow fittings and a new method of wringing the pipe edge have been developed and put in practical use. Concerning the relationalization and improvement of the efficiency of the pipe fabrication process, we have noted the need of changing the existing method of using elbo fittings into that of pipe bending by using a short bending radius 1∼1.5 D (D: pipe diameter). So, we have successfully developed, through many systematical experiments, a new pipe bending process using short bending radius thereby breaking the common sense of pipe bending radius resulting in a fair extension of the range of application of short bending radius. Concurrently we have developed a new manufacturing method of wringing (reducing) the pipe edge thereby securing a substantial saving of the working time in the assembling and welding stages and the improvement in the quality of the wringing part. These new manufacturing methods can be expected to be applied in the field of not only ship construction but also land plant thus allowing to fabricate pipes at a remarkably lower cost. The following is a report on the new manufacturing methods.
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Masaki WATANABE, Shigeki SHIMIZU, Hideo KITAGAWA, Masazou SHIMIZU
Article type: Article
Pages
22-30
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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The directionality of tensile properties and impact values of heavy plate (150 mm thick.) for boiler was experimentally studied. We obtained the following results. (1) Tensile test a) No directionality was found in tensile strength and yield point. b) Elongation and reduction of area decreased as the angle between the axis of the test specimen and the rolling surface or direction increased, especially in the thickness direction the reduction of area markedly decreased. c) Nominal stress-strain curve for each direction was nearly same and the directionailty were observed after the yield point on the nominal streess-strain curve. Especially in the thickness direction, fracture occurred slightly above the yield points. d) Each specimen generally followed the same true stress-strain curve, but the true stress and strain at the fracture point larger was in the rolling direction than in the trasverse direction, and larger in transverse direction than in thickness direction. e) The fracture appearance of the specimens in the thickness direction and near the direction was brittle resulted in lamella tearing. The non-metalic inclusion were found in the planes parallel with the rolling surface. The directionality seemed to be caused by notch effect of these nonmetalic inclusion. (2) Impact test a) Impact values decreased as the angle between the axis of the test specimen and the rolling surface or direction increased. In the thickness direction, the impact value for the transverse direction was larger than that of the specimen which had a notch in the rolling direction. b) It was found that non-metalic inclusion existed parallel to the rolling surface and further extended toward the rolling direction than toward the transverse direction. As a result, the impact value in the transverse direction decreased in comparison with in the rolling direction; and in the thickness direction, the impact value of the specimen which had a notch in transverse direction was larger than the specimen which had a notch in rolling direction. c) The influence of directionality was not so severe as in the case of other reports. It is owing to the configuration of the non-metalic inclusions, which is not as long in the rolling direction as in the case of those reports because this steel plate is thicker and its rolling ratio is smaller. d) The 3.5 kg-m/cm^2 transition temperature was lower in the rollig direction than in the transverse direction, and also were lower in the transverse direction than in the thickness direction. e) No directionality was found in the energy transition temperature. f) The fracture section of the thickness direction was slightly different from the brittle fracture as usually observed. It had many lamella tearings.
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Osamu KAWADA, Hideaki KUSUNO, Yutaka ISHIDA
Article type: Article
Pages
31-37
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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It is well known that the frictional resistance of ships increases remarkably when the surface conditions are changed by marine growth attached to ship's bottom or due to other causes. However it has not been quantitatively studied yet how great their effects on friction resistance are. Hence, with the aim to clarify these effects on friction, several painted surfaces are tested by a rotating disk method and the frictional resistance is measured as a from of torque. It is found that coating films which are not sufficiently dried or to which marine growth attached increase frictional resistance, but small blisterings or peelings of coating films scarcely increase it.
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Matao TAKAGI
Article type: Article
Pages
38-47
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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The theory of higher order wave-making resistace of Michell type ship were developed by Sisov, Maruo and Wehausen etc... In this report, the relationship between the theories are discussed and the velocity potentials and the formulas of the wave-making resistance obtained there are investigated in various phases. The results clarified that Sisov-Maruo theory is based on the analytical continuation of the boundary conditions on wave surface and ship surface to those on the free surface of the still water and the center plane of the ship, respectively, and hence the boundary condition of the ship surface above the free surface of the still water cannot contribute to the solution. It is also shown that the term of the line integral corresponding to the water line is useless. The above is recognized from the fact that, while the formulas of the wave-making resistance derived by the method of pressure integral and momentum theory coincide with each other in case of the velocity potential without the line integral, they do not in case of that with the line integral.
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[in Japanese]
Article type: Article
Pages
48-51
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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[in Japanese]
Article type: Article
Pages
52-54
Published: June 30, 1970
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Article type: Appendix
Pages
55-57
Published: June 30, 1970
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Article type: Appendix
Pages
App1-
Published: June 30, 1970
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Article type: Appendix
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Published: June 30, 1970
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Article type: Appendix
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Published: June 30, 1970
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Article type: Appendix
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Published: June 30, 1970
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Article type: Appendix
Pages
App5-
Published: June 30, 1970
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Article type: Appendix
Pages
App6-
Published: June 30, 1970
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Article type: Cover
Pages
Cover3-
Published: June 30, 1970
Released on J-STAGE: February 25, 2018
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