Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 66, Issue 7
Displaying 1-34 of 34 articles from this issue
  • Atsuyoshi SHIBUYA, Tatsuo KURIMOTO, Kimitake KOREKAWA, Kohji NOJI
    1980 Volume 66 Issue 7 Pages 771-778
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The Ni-Zn electroplated steel sheet was studied in order to improve the corrosion-resistance of the Zn electroplated steel sheet.
    In a sulfate bath, Ni-Zn alloy was plated on steel sheets under the high current density (20A/dm2). The relationships among Ni content in deposited film, deposited phase, and corrosion resistance were investigated, and the corrosion behavior of the Ni-Zn plated steel sheet was discussed.
    The results are summarized as follows:
    (1) Under high current density as well as under low current density, γ-phase of Ni-Zn alloy deposits preferentially, and the deposited film is of dual phase consisting of η+γ for low nickel content, or of α+γ for high Ni content.
    (2) The film of γ-phase consisting of 10%16% nickel content shows the best corrosion resistance with a good lustrous appearance, and protects the steel well. The film of dual phase of γ+α shows the less corrosion resistance than one of dual phase of γ+η.
    (3) It is supposed that good protection of γ-phase film is based on the corrosion potential of this film being less noble than the steel, and changing to more noble site by concentrating of nickel on the corroded surface during the corrosion advancing.
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  • Takahisa YOSHIHARA, Hajime KIMURA, Shunichi HARADA
    1980 Volume 66 Issue 7 Pages 779-789
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Significant improvement of corrosion resistance of electrogalvanized steel sheet has been accomplished by codepositing particles (-250 mesh) of metallic aluminum in zinc layer. The composite coating is obtained electrolytically using a new plating bath containing zinc ion and aluminum particles dispersed.
    The properties of Zn-Al composite electroplated steel sheet depend on the content of aluminum particles and the distribution of them in the plated layer. It has been found that the corrosion resistance by salt spray test is significantly improved with an increase of aluminum content in the plated layer.
    Drawability, spot weldability and ED paint adhesion are also superior to those of electrogalvanized steel.
    The corrosion mechanism of composite electroplated steel sheet has been studied by using electro-chemical methods. It becomes clear that the codeposited aluminum particles in plated layer act as cathodes and the cathodic reaction is suppressed by the existence of some resistive film on aluminum surface, and, as a result, anodic dissolution of zinc in plated layer is remarkably decreased.
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  • Satoshi KADO, Saburo AYUSAWA, Takashi WATANABE
    1980 Volume 66 Issue 7 Pages 790-796
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    As a result of extensive study, a new Zn (under layer)/Mn (top layer) coated steel sheet having excellent corrosion resistance, formability and weldability has been developed. The corrosion resistance of this dual coating is superior to those of other single layer coatings or alloy coatings especially in the environment of salt water.
    The layers of Zn and Mn, being electrochemically baser than steel, protect the steel substrate effectively. Besides it has been confirmed that the corrosion products of Mn form a sort of film which acts as a protective barrier.
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  • Keiji ARIGA, Katsumi KANDA
    1980 Volume 66 Issue 7 Pages 797-806
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The corrosion resistance of Zn-Co based Co-electrogalvanized steel sheet has been investigated, and the effect of the additional elements (Co and Mo) containing in deposit on the corrosion behavior has been considered.
    (1) Zn-Co-Mo plating is proved to withstand about 4 to 6 times longer, in the occurrence of red rust by salt spray test, than Zn plating, and has an excellent resistance against the deterioration of PVC adhesion under salt spray test.
    (2) After the salt spray test, the corrosion potential of Zn-Co-Mo plating moves slowly to the Fe. On the other hand, that of Zn plating moves rapidly to the Fe potential. Though the initial corrosion current of Zn-Co-Mo plating is larger than that of Zn plating, the corrosion current of Zn-Co-Mo plating tends to be reduced with the corrosion progress, and it becomes smaller than Zn plating after all. The cathodic reaction of Fe exposed by the dissolution of Zn and the anodic reaction of Zn are controlled by the corrosion products containing the composite compounds of basic cobalt chloride and Mo (OH)3, so that the corrosion of Fe and the occurrence of red rust is restrained. Also, the corrosion resistance of PVC coating on Zn-Co-Mo plating steel sheet is superior to that on Zn plating steel sheet.
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  • Toshio FUKUZUKA, Kazuichi KAJIWARA, Kenji MIKI
    1980 Volume 66 Issue 7 Pages 807-813
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Processes for the zinc-iron alloy electroplating on steel sheets, and the properties of these alloy electroplated steel sheets in comparison with the zinc electroplated steel sheets, were described.
    (1) The composition of zinc-iron alloy electroplating was varied with the bath compositions and plating conditions, the iron content of the plating increased with the increase of iron content to zinc content in the bath, the plating current density and the pH of the plating bath, and decreased with the raise of bath temperature.
    (2) Zinc-iron alloy electroplated steel sheets showed the good spot weldability according to the increase of the iron content of the plating, and this tendency was remarkable when the welding current was low.
    (3) Zinc-iron alloy electroplated steel sheets with the iron content of 7% to 25% showed the best corrosion resistance and also the red rust produced on the plating was least.
    (4) Zinc-iron electroplated steel sheets on which the electropainting was applied after phosphate treatment also showed better corrosion resistance than the zinc electroplated steel sheets according to the increase of iron content of plating.
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  • Kazuo MATSUDO, Takeshi ADANIYA, Masaru OHMURA, Masahiro OGAWA
    1980 Volume 66 Issue 7 Pages 814-820
    Published: June 01, 1980
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    In order to develop the electrogalvanized steel with high corrosion resistance, conventional electrogalvanizing bath was modified with an addition of Co and Cr compounds. This newly developed coated steel is called FZ. FZ is produced by conventional electrogalvanizing process using a composite electrolyte containing small amount of cobalt and chromium ions. The corrosion resistance of the product is twice as high as the conventional electrogalvanized steel. The other properties such as formability and weldability are quite the same as conventional one. Chromate-treated and phosphate-treated products are also manufactured and their corrosion resistance and paint adhesion are excellent as well.
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  • D.J. BLICKWEDE
    1980 Volume 66 Issue 7 Pages 821-834
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Based on extensive studies of 1 to 70% Al-Zn alloy coatings on sheet steel, the 55% Al-Zn alloy coating was found to have the optimum combination of corrosion resistance, heat resistance and galvanic protection of sheared edges of sheet. This paper reviews the corrosion and heat resistance of this new coated sheet product under various service conditions, as well as paintability, formability and weldability. This new coated sheet product is in commercial production now in the United States and Australia ( John Lysaght, Ltd, Inc) and will be produced soon in Sweden (Svengt Stal). The various commercial applications for this product are described.
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  • Takeshi ADANIYA, Masaki ABE, Masahiro SHOJI, Hidekatsu YANO
    1980 Volume 66 Issue 7 Pages 835-844
    Published: June 01, 1980
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    The relations between coating weight and control factors are investigated quantitatively in order to clear the mechanism of the gas wiping process. A fundamental equation model proposed from an analysis of the results is as follows :
    W=K0P-K1DK2VK3 exp(K4/V)
    where,
    W : coating weight (g/m2·both sides)
    P: gas pressure at nozzle header (kg/cm2·G)
    D : distance between nozzles (mm)
    V : line speed (m/min)
    Although coefficients vary with the working conditions, this equation gives coating weight in the range of 7% standard deviation of error for our commercial line (K0=0.45, K1=0.63, K2=0.88, K3=0.50, K4=8.3).
    Important factors for efficiency are the gas itself and the slit gap of nozzle. For minimization of the friction loss at nozzle, the selection of low viscous gas and relative large slit gap are effective.
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  • Toshio FUKUZUKA, Masaaki URAI, Kenji WAKAYAMA
    1980 Volume 66 Issue 7 Pages 845-851
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Design and construction have been made on a new hot galvanizing apparatus which successfully galvanizes one-side of a steel strip by spouting molten zinc upwards through an electromagnetic pump. This apparatus also has a gas-wiping device to control the weight of coated zinc just after galvanizing. The results obtained are as follows :
    (1) The electromagnetic pump can easily spout up molten zinc to sufficient height to perform one-side galvanizing.
    (2) The spouting nozzle should be wider than the width of the steel strip to ensure galvanizing of the whole surface.
    (3) The uncoated side was contaminated by molten zinc stuck to the guide roll surface on the outer side of the steel strip in case the guide roll was wholly made of steel. This contamination, however, could be avoided by covering the guide roll with a graphite or ceramics, to which molten zinc does not stick.
    (4) The weight of coated zinc decreased drastically with an increase in the flow rate of the wiping gas, so that the weight of coated zinc could be minimized to 20 g /m2.
    (5) The zinc coating obtained showed good quality and the oxide film on uncoated side was very thin.
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  • Minari GOTOU, Hideo KOUMURA, Yoshinori FUJITA, Shunichi HARADA
    1980 Volume 66 Issue 7 Pages 852-857
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    A new method of one-side galvanizing using a suitable stop-off coating in continuous inline type hot dip galvanizing line (CGL) has been developed. The stop-off coating is a water slurry comprising of water glass, alkali, H3BO3 and MgO or Mg(OH)2. The process is a continuous stepwise treatment system of cleaning-coating of the slurry-firing (combined with anneal)-galvanizing-removing of stop-off coating film.
    One-side galvanized steel manufactured by this process offers a good corrosion resistant material for automobile body. Galvanized side of the product has good corrosion resistance and strong sacrificial corrosion protectability as a conventional galvanized steel sheet. These properties are effective in controlling aggressive local corrosion such as 'perforation' at the inside surface of auto body. The bare steel surface on the reverse side has good appearance similar to the conventional cold rolled steel sheet and better rust resistance, phosphatability and higher resistance against under-film corrosion. This superior corrosion resistance of the bare side of the one-side product originates in its exceptionally pure surface layer which is caused by cleaning action of the stop-off coating during annealing in CGL.
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  • Yasuhiko MIYOSHI, Katsuyoshi YOSHIDA, Tadao AZAMI, Tatsuya KANAMARU, S ...
    1980 Volume 66 Issue 7 Pages 858-867
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Corrosion behavior of electrophoretically coated galvannealed-, galvanized-, and cold rolled steel sheet was investigated by salt spray test, cyclic corrosion test, 5% NaCl immersion test and heat cycle test. Galvannealed steel showed the best resistance against rust formation, followed by galvanized steel. Brown rust developed easily on cold rolled steel. Galvannealed steel also has the best resistance against blistering and galvanized steel the worst. This was confirmed by the direct observations of film exfoliation of specimens partly covered with clear lacquer in corrosive environments. According to the electrochemical experiments galvannealed steel, although its surface layer consists of Fe-Zn alloy, behaves like galvanized steel on the early stage of corrosion. Zinc corrosion products cover its surface under the film and suppress rust formation.
    Scanning electro microscopic observations revealed that on galvanized steel Zn/phosphate interface under the film is attacked by OH- ions formed by cathodic reaction. This results in film exfoliation. On the other hand Fe-Zn/phosphate interface on galvannealed steel is not damaged easily by OH- ions because of the roughness of the Fe-Zn alloy surface, which brings about good film adherence.
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  • Motoharu HAMADA, Hiroshi KUBO, Shun-ichi HARADA
    1980 Volume 66 Issue 7 Pages 868-874
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    An improved powder coating process to make a pure aluminum coated steel sheet has been developed by using a continuous pilot production line. This process is composed of preliminary coating of thin zinc layer, coating of aqueous slurry of aluminum powder, light rolling and heating at 500600°C. Preliminaly zinc coating of 0.03 to 0.1 μm thick is found to be very effective to improve the adhesion of aluminum film on the final product. By applying this method, it also becomes possible to add some special thickeners into aqueous slurry of aluminum powder, which strengthen the cohesive force of aluminum powder to base steel sheet during the coating process.
    The product is characterized by pure aluminum coating up to 60 μm thick having attractive bright appearance, negligible pinholes in aluminum film, good film adhesion and excellent corrosion and heat resistance. The product can be bent tightly up to 180° and can be deep-drawn without exfoliation of coated aluminum. The surface of the product can be colored electrolytically just like as pure aluminum metal and also can be enameled.
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  • Hisao TAKAMURA, Noboru KONDOU
    1980 Volume 66 Issue 7 Pages 875-881
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • Yoshio OKI, Yoshiyuki SUGIMOTO
    1980 Volume 66 Issue 7 Pages 882-892
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • Haruki FUJII, Yasuro KANAZAWA, Isao MIYAWAKI
    1980 Volume 66 Issue 7 Pages 893-904
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • Yoshiaki OHYABU
    1980 Volume 66 Issue 7 Pages 905-917
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
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  • Yutaka HAYASHI, Tetsuzo ARAI
    1980 Volume 66 Issue 7 Pages 918-923
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • Ryuji KOJIMA, Hiroshi OKITA, Yasunobu MATSUSHIMA
    1980 Volume 66 Issue 7 Pages 924-934
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • Toshio FUKUZUKA, Kazuichi KAJIWARA, Kenji MIKI, Shigeki KIRIHARA, Tomo ...
    1980 Volume 66 Issue 7 Pages 935-944
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Car bodies made of cold rolled steel sheets are phosphated and electro-painted. In these processes, the surface contamination of cold rolled steel sheet may have influence on the performance of phosphate coating and that of paint coating.
    In this work, the influence of surface film on corrosion resistance of cold rolled steel sheet afterward phosphated and electro-painted was studied.
    The results obtained are as follows
    1. The thickness of oxide film and that of carbonaceous film on steel sheet could be measured by ellipsometry.
    2. In order to heighten the corrosion resistance of electro-painted steel sheet, oxide film needs to be controlled thinner than 160Å, and also carbonaceous film needs to be controlled thinner than 40Å.
    3. The thickness of oxide film was in the range of 31Å to 102Å, and that of carbonaceous film was thinner than 35Å, when cold rolled steel sheet was degreased by electrolytic method, and then annealed by open-coil method.
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  • Shigeru WAKANO, Noriaki USUKI, Minoru NISHIHARA, Nobukatsu FUJINO
    1980 Volume 66 Issue 7 Pages 945-952
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The effects of the segregation of some elements and the transmutation of surface oxide film induced during box annealing on the phosphating of cold rolled steel sheet have been studied through the measurement of spontaneous potential in the KH2PO4/NaOH buffer solution of pH 7 and the surface analysis by IMMA, ESCA and F. X..
    The first stage of the phosphate reaction is the dissolution of oxide layer at the steel surface. The dissolution rate of oxide film depends largely on the bonding state of oxygen in the surface (whether Fe-O bond or Fe-OH bond).
    The layer having Fe-OH bond decreases the rate of phosphate nucleation.
    The second stage is the growth of phosphate film. It is considerably affected by the enrichment of Mn and P at the steel surface that occurs during annealing. These elements are identified as the oxide state and have influence on the dissolution of iron, because of constituting the local cell with matrix iron. The Mn enrichment accelerates iron dissolution and so enhances the growth of phosphate film. But the P enrichment behaves oppositely.
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  • Process and Coatings
    Norio NIKAIDO
    1980 Volume 66 Issue 7 Pages 953-963
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
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  • Hiroshi KAGECHIKA, Yoshinori YOMURA, Tomihiro HARA
    1980 Volume 66 Issue 7 Pages 964-970
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The uniformity of initially deposited layers will affect the corrosion resistance of electro-tin-plate, especially its iron solution value (ISV). The uniformity of initially deposited layers, which can be evaluated by ADC test (Anodic Dissolution Current Test) developed in our laboratory, will vary with change in plating current density and the chemical composition of the plating bath. It is most affected by the concentration of leveling agent. The initially deposited layers become more uniform with increase in the concentration of leveling agent. The result seems to be different from the usual concept of the optimum concentration of leveling agent in the plating bath. However, the present result is effective only in the initial stage of electrodeposition which ends when 1. 2g/m2 tin is deposited on the substrate surface. In the following second stage in electroplating, high concentration of the leveling agent gives adverse effect on the corrosion resistance. On the basis of the result above, two-step electro-tin-plating processs has been introduced, which has independently controlled initial and the second plating processes. It is shown that the electro-tin-plate made by this two step process has high corrosion resistance.
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  • Yoshiaki SHIMIZU, Iwao MATSUSHIMA
    1980 Volume 66 Issue 7 Pages 971-978
    Published: June 01, 1980
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    The Alloy-Tin (ATC) and Iron-Solution (ISV) tests are generally accepted to evaluate the corrosion resistance of electrolytic tinplate in plain cans for moderately acid foods. The relative potential difference between alloy-layer and base steel, which mainly depends upon the electrochemical characteristcs of steel, plays an important role to these test results.
    It is also described that the corrosion resistance of tinplate can be measured by means of proper evaluation ways, such as newly developed ASC(Alloy-Steel Couple), TAG (Tinplate-Alloy Couple) tests and polarization technique, which directly correlated with each corrosion process of tinplate in plain cans in moderately acid foods.
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  • Hajime NITTO, Yashichi OYAGI, Hirohumi NAKANO
    1980 Volume 66 Issue 7 Pages 979-985
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Effect of the plate qualities was studied on property of surface lubrication that is necessary for DI can fabrication.
    DI canmaking energy was newly used besides the forming load as a means of evaluation on the property of lubrication. It was found that the value of this energy could be a standard of the evalution to the die life of the commercial DI machine. Therefore this energy was found valid as the means of the valuation of tin plate qualities.
    In tin plate qualities the factors that affected DI canmaking energy were tin coating weight, tiniron alloy layer amount, chemical treatment, sheet thickness, temper grade. Surface roughness of the original sheet was hardly effective on DI canmaking energy.
    But it was considered that surface roughness was effective on the die life. Because surface roughness was effective on the tin corevage of the can wall at DI process.
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  • Katsuyoshi YOSHIDA, Akihira SUZUKI, Kazuyuki DOI, Katsutoshi ARAI
    1980 Volume 66 Issue 7 Pages 986-991
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    It has been shown by the electron microscope that the unusual surface color which occurs sometimes on the TFS is caused by small projections of deposited metallic chromium.
    As the upper layer of the cathode film of the chromium plating is easily soluble into the electrolyte, small local defects of the cathode film are produced by dissolution when the steel strip runs from one plating cell to the following cell, because plating current is not applied between the plating cells. The metallic chromium deposition in the next plating cell occurs preferentially at the site of the local defects and forms the projections there.
    This theory agrees well with authors study on the cathode film that the metallic chromium deposits not from the cathode film but chromium complexes by penetrating the cathode film and reaching strip surface.
    Low current density pretreatment in each plating cell is effective for the prevention of the unusual color on the surface.
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  • Seishichi KOBAYASHI
    1980 Volume 66 Issue 7 Pages 992-999
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • Motoharu NAKAMURA, Hiroshi OKADA, Kiyoshi MATSUI, Minoru KITAYAMA
    1980 Volume 66 Issue 7 Pages 1000-1009
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    A study on the punchability and weldability of electrical steel sheets with the insulting coating has brought to the following conclusions:
    1) A new inorganic-organic insulting coating improves the punchability of electrical steel sheets by more than 30 times compared with the conventional inorganic insulating coating.
    2) The reason for this marked improvement in punchability cannot be explained by the shearing energy involved.
    Probably, the addition of organic matter decreases the side wear of the punch.
    3) The weldability of electrical steel sheets with the new insulating coating is impaired by the gas evolved through the thermal decomposition of organic matter contained.
    Release of this gas from around weld beads can enhance weldability.
    An industrially advantageous method is to roughen the electrical steel sheet or the insulting coating itself.
    In this way, a process has been established under which an inorganic-organic insulating coating is used as the surface coating of electrical steel sheets to satisfy their punchability and weldability requirements at the same time.
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  • Toshikuni TANDA, Tomoyuki ICHI, Nobuyuki MORITO, Toshio IRIE, Hiroshi ...
    1980 Volume 66 Issue 7 Pages 1010-1016
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    In addition to magnetic properties, excellent punchability and TIG weldability are required for nonoriented electrical steel sheets. These properties depend not only on the mechanical properties and chemical composition of steels, but also on the character of insulating coating applied to steel sheets.
    This report provides an outline of development in Kawasaki Steel Corporation during the last decade in insulating coating improving the punchability and weldability of electrical steel sheets. The first success in improvement of punchability was established by the chromate coating obtained by the solution with the specific composition of Ca/CrO3=0.195. This coating is significant as the basis of the subsequent development in insulating coatings with respect to punchability.
    The next developed coating, composed of the chromate-organic resin double layered film, had better punchability as compared with other insulating coatings at that time. This coating, however, had poor TIG weldability, and further development has been made and succeeded to solve this problem.
    The chromate-organic resin mixed coatings with smooth surface and with the agglomerated coarse particles in its own film are, in present, applied to electrical steel sheets. These newly developed coatings have both excellent punchability and TIG weldability.
    The change in structure of the chromate coating and chromate-organic resin mixed coating during baking has also been investigated by means of infrared absorption spectra.
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  • Keinosuke TSUJI, Youichi NAKAGAWA
    1980 Volume 66 Issue 7 Pages 1017-1027
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
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  • Kunitoshi KIMURA, Koji NOJI
    1980 Volume 66 Issue 7 Pages 1028-1034
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • Mansei TANAKA, Fuyuhiko OTSUKI, Hiroshi YOSHIDA, Morihiro WADA
    1980 Volume 66 Issue 7 Pages 1035-1041
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    A polyethylene coating process that uses a flat-die extrusion method has been developed by Nippon Steel Corporation and others to manufacture polyethylene coated large-diameter steel pipes.
    They are used in pipelines for the long distant transportation of natural gas or oil.
    In this process, the molten polyethylene sheet is wound around the pipes as they rotate and advance on the skew rolls. The new developed process is able to meet changes in pipe diameter and coating thickness with a single size of die. The properties of molten polyethylene give an important influence on the good appearance and uniformity of the polyethylene coating. Accordingly, it is necessary to use polyethylene with a high melt strength, a low melt index and a low shrinkage stress.
    Furthermore, rapid cooling after the polyethylene coating is necessary to guarantee excellent impact resistance of the coated pipes at low temperatures.
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  • Yukichi WATANABE, Tadao KIMURA
    1980 Volume 66 Issue 7 Pages 1042-1046
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The portable asphalt coating equipment, as a new method of asphalt coating for the reduction of negative friction acting to piles, has been developed. The asphalt sheet, cooled and shaped by the rotary cooling drums, is winded to the steel tube, while the asphalt has the plasticity in a certain range of temperature.
    The characteristic feature of this equipment is as follows:
    (1) The equipment is compact and able to coat asphalt easily at the site where piles are drived. Thus the problems encountered on the transportation or the storage, i. e. damages of coating, can be settled.
    (2) The coating thickness is uniform over the whole length of piles, as a result of coating method of sheet winding. Also, coating adhesion is excellent. By the actual piling test, the coated piles produced by the new method were confirmed to be able to put to practical use.
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1980 Volume 66 Issue 7 Pages 1048-1054
    Published: June 01, 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • 1980 Volume 66 Issue 7 Pages N176
    Published: 1980
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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