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Volume 21, Issue 4
Displaying 1-30 of 30 articles from this issue
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Nakaaki Oda, Nagaharu Morioka, Sadayuki Tunoo1957 Volume 21 Issue 4 Pages 199-203
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSome of the materials submitted to our spectrographic laboratory for analysis are in the forms of powder,grains chips, and scraps which are not suitable for electrodes in condensed spark tests from the viewpoint of sample shape and segregation of impurities in metal.If the sample ingot is not uniform due to the segregation effect, fine sample chips or drilling are collected from various positions including the representative constituents of ingot, by means of grinding, shaving or double boring technique. The obtained fine drilling, shaving or grinding materials are pulverized into the range of 40∼100 meshes. This powder may be briquetted (40∼80 kg/cm2 for Pb and Zn) into solid rods presenting a homogenous surface for spark excitation, under which condition accurate analysis can be made spectrochemically as well as cast and machined metal electrodes. A briquetting die for making solid rods of 5 mm in diameter and 25 mm in length is described. A comparison of briquetted rod and cast rod on zinc and lead showed that the precision, the accuracy and the spectral sensitivity obtained by this briqette method are comparable with those obtained by the conventional cast electrode method. This technique can be applied also to preparation of spectrochemical standard metal electrodes.View full abstractDownload PDF (752K) -
Itsurô Tatsukawa1957 Volume 21 Issue 4 Pages 203-206
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn this article, slow bending test, hardness test and dilatometric examination as well as magnetic analysis were carried out on 0.8%C steel wires variously hot-bath quenched at temperatures both above and below the Ms temperature, through which the relationship between the toughness and the structural constituents were discussed. The shapes of the curves of the absorbed energy for fracture in bending test against the holding time in isothermal treatment at every temperature are similar in general whether the soaking temperature is above or below the Ms point ; that is, every curve has a maximum value at the soaking time when the structure of the specimen consists of lower-bainite, tempered martensite and a lot of retained austenite, the last one causing improved toughness. Furthermore, from these results, it is found that retained austenite decreases yielding stress, and also superior toughness with high hardness is obtained even by certain hot-bath quenching in martensitizing range similarly as by austempering in lower-bainitizing range compared with the case by ordinary oil-quenching and tempering.View full abstractDownload PDF (661K) -
Sigeo Ôwaku, Kazuaki Iijima1957 Volume 21 Issue 4 Pages 206-210
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of quenching methods—semi-rapid heating and quenching, and ordinary quenching— on the hardness, the fatigue limit and the bend-breaking stress have been studied with quenched and tempered 0.81%C steel wire specimens. The results were as follows: (1) The hardness differences due to these two quenching methods are negligibly small. The hardness decreases nearly continuously as the tempering temperature rises. (2) The fatigue limit differences due to the quenching methods are also small when the tempering temperature is higher than 300°. The fatigue limit decreases as the tempering temperature rises, consequently as the hardness decreases. (3) But the fatigue limit and the band-breaking stress differences are noticeably larger, when the tempering temperature is lower than 300°. Semi-rapid heated and quenched specimens show superior values as compared with ordinary quenched ones. And these properties are improve as the tempering temperature rises. (4) The above results can be explained by the negative effects on the properties of quenched steel of the microstress induced by martensite formation in each austenite grain.View full abstractDownload PDF (538K) -
Hiroshi Asada, Kichizô Koike, Saburô Morimoto1957 Volume 21 Issue 4 Pages 210-213
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of manganese content and of the extrusion conditions on the recrystallization temperature of aluminium alloys were investigated and the following results were obtained. (1) According to the microhardness test of cold-rolled high purity Al-Mn alloys, it appears that the manganese content dissolved in solid solution is effective for the elevation of the recrystallization temperature. (2) With the extruded commercially pure Al-Mn and Al-Cu-Mn alloys, the elevation of the recrystallization temperature is proportional to the increase of Mn and Cu contents. (3) The recrystallization temperature drops by higher extrusion ratio or lower extrusion temperature. (4) From the above results it may be concluded that hot-working by extrusion gives the same influence as cold-working on aluminium alloys.View full abstractDownload PDF (622K) -
Shigeo Wakamatsu1957 Volume 21 Issue 4 Pages 213-217
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA new gravimetric method for the determination of zinc in iron, steel, iron ores and aluminum alloys has been developed. As the reagent, acridine and ammonium sulphocyanide were used to precipitate zinc in the presence of iron (II), nickel,aluminium, chromium, vanadium (IV), manganese,calcium and magnesium. The precipitate was ignited at 950°. By varying the procedure slightly, cobalt and molybdenum could be also determined. The described procedure offers a rapid, accurate method for analyzing zinc in metal and ore.View full abstractDownload PDF (720K) -
Hideo Takei1957 Volume 21 Issue 4 Pages 217-221
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn this paper, the changes of the rigidity modulus, the electrical resistivity and the hardness due to cold-drawing and annealing were measured for phosphor bronze and nikel-silver wires which are used as spring materials. The measurements were made by the use of a torsion pendulum, a potentiometer and a Micro-Vicker’s hardness tester. The results obtained are as follows: (1) The rigidity modulus of phosphor bronze increases with the amount of cold-drawing to the reduction of area less than 45%, and is almost constant at 45∼70% reduction,but,gradually decreases by the heavy drawing above 80% reduction. The electrical resistivity and the hardness rise linealy with the reduction in area. (2) The rigidity modulus of nickel-silver decreases remarkably with the amount of cold drawing up to 80% reduction. The electrical resistivity also rises remarkably with the reduction of area, though a small increase in resistivity was found at the early stage of drawing. (3) Though the rigidity modulus of the phosphor bronze wire of 91% reduction slightly increases by annealing at 150∼250°, a remarkable increase of rigidity, which seems to be the result of recrystallization, takes place at the annealing temperature between 250∼350°. The maximum value of the rigidity modulus was obtained by annealing at 350°. (4) In case of nickel-silver wire of 91% reduction, the rigidity modulus increases with the annealing temperature above 150°, and at 450∼500°, in which recrystallization takes place, the increase becomes remarkable. The maximum value of rigidity modulus was obtained at 500°.View full abstractDownload PDF (706K) -
Minoru Tanaka, Sôkichi Umekawa1957 Volume 21 Issue 4 Pages 221-225
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe load-time curves in the Charpy impact bending tests have been obtained by a new-designed impact force detector using Rochelle salt crystal, such as shown in Fig. 1. After many tests for high-strength structural steel, heat-treated tool steel and pure copper, the breaking behaviours in Charpy impact bending tests were classified into four types as represented schematically in Fig. 3a, b, c and d. Consequently, the meanings of Charpy values should be distinguished between the materials broken off in the type of Fig. 3a or b, and in the type of Fig. 3c or d, even when the Charpy values were the same. From the results obtained on the high-strength structural steel, Welten, produced in Japan, it has become known that a suitable normalizing will improve remarkably the cold-notch shortness of the hot-rolled plate, as shown in Photo. 5 and 6.View full abstractDownload PDF (665K) -
Sadao Koshiba, Kazuo Tanaka1957 Volume 21 Issue 4 Pages 225-227
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of subzero treatment on the cutting durabilities and the deflective strength of four kinds of high-speed steels, namely, low-tungsten high-speed steel, low-tungsten-cobalt high-speed steel, molybden-tungsten high-speed steel and 18-4-1 steel were investigated. It was found that the cutting durability of subzero-treated specimen after oil-quenching was almost the same as compared with that of a specimen which was repeatedly tempered after oil quenching,and that the deflective strength of the former was equal to or was smaller than that of the latter. From the results of these investigation, it was concluded that the subzero-treatment on cutting-durability of high-speed steel due to lathe-cutting was not very effective.View full abstractDownload PDF (402K) -
Masao Kondô, Takeji Hachisuka1957 Volume 21 Issue 4 Pages 227-230
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUsing high-carbon low-chromium bearing steel, the effects of quenching temperature, martempering and tempering on repeated sabzero-treatments at various treating temperatures were studied. The behavior of retained austenite which transformed to martensite during subzero-cooling was predicated on measuring the change in hardness and dilatation curve. The results obtained are as follows: (1) Changes in hardness and length occured mainly during the first or second subzero-cooling under any treating condition. (2) The higher the quenching temperature and the lower the subzero-temperature, the wider changes in hardness and length resulted with the exception of −183° subzero-cooling. (3) Martempered specimens were subject to more changes in hardness and length than quenched specimens. (4) The specimens tempered at 100° and 150° for 1 hour showed athermal and isothermal expansion during subzero-cooling respectively, but those tempered for 30 minutes at the same temperatures did neither.View full abstractDownload PDF (578K) -
R. Yamada, K. Yokoyama, T. Nakamura, F. Urushibara1957 Volume 21 Issue 4 Pages 230-234
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSome specimens were prepared either by vacuum melting in a high-frequency induction furnace or by melting in atmosphere from the same materials. The strain age-hardening of these specimens was experimented in comparison with that of some commercial steels. With vacuum-melted specimens, the increase of tensile strength in the blue heat range became very little and sometimes even imperceptible. With steels of high carbon content (0.8%C), the blue heat range removed toward the high-temperature side and was distinctly observed even in specimens of vacuum-melted steels. The strain age-hardening after cold-rolling appeared more delayed with vacuum-melted steels just like in the case of quench-aging. The hardening values in the case of strain age-hardening revealed not so much difference due to different melting methods as the blue shortness.View full abstractDownload PDF (564K) -
Tomo-o Satô, Saburô Toya1957 Volume 21 Issue 4 Pages 234-238
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFirst, this paper deals with the graphitization of cast graphitic steels containing 1.0∼1.8%C and 1.5%Si by annealing under several conditions. Second, some mechanical properties of these cast steels graphitized by several heat treatments were measured. As the result of the present study, it has been found that, (1) The time for graphitization at 800∼1000° is decreased by forging of cast specimens. (2) These cast steels containing more than 1.4%C easily graphitize by annealing at 950° for 3 hrs and cooling at the rate of 50°/hr, and then spheroidal graphite is obtained. (3) The highest tensile strength and the elongation of these steel specimens are shown by those containing 1.4∼1.6%C and 1.5%Si.View full abstractDownload PDF (901K) -
Ichiji Obinata, Kensuke Kurihara, Yô Takeuchi, Rokurô Kawa ...1957 Volume 21 Issue 4 Pages 238-241
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDropping molten aluminium droplets weighing about 2 grams into water heated at various temperatures, the process of their solidification has been observed through peeping window set in the side of water tank. The results of observations may be summarized as follows: The shape of the solidified granules depends chiefly on the temperature of water rather than the distanceof falling to the surface of water or the temperature of molten aluminium : If the temperature of water lies between 10° to 30°,the granules obtained showed always a irregular flat form. When the temperature of water was raised to 40∼60°, the major drops solidify in a hollow spherical form ; while, above 60°, keeping the drops in their molten state for a few meters of free sinking in the water, they solidify at last in a compact tad-pole form. From the above observations the present writers have devised a method of obtaining spherical granules of aluminium : The method consists essentially in rotating the molten aluminium droplets, by means of guide plates set in the water tank, during their sinking in the water heated at above 60°.View full abstractDownload PDF (998K) -
Masuji Kyotani1957 Volume 21 Issue 4 Pages 241-245
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present paper deals with the experimental results on the zone refining of zinc. Study was made of the room temperature recrystallization characteristics and of the impurity substructure of zone-melted zinc. The results obtained were as follows: Spectrographic analyses were made, and they showed clearly that three of the main four impurities—lead, cadmium, copper and iron— have been reduced in concentration, that is, lead and cadmium were segregated at the finishing end and copper were segregated at the starting end of the ingot. Therefore, a portion of very high purity was found in the midsection of the ingot. The impurity substructure has been observed at the end portion of zone-melted bar, and the length of the portion of the impurity substructure was changed by the number of the passages of molten zones. The recrystallization of 20 pct cold-reduced molten bar was found to be complete in the entire midsection of the ingot in as little as 1/2 hr at room temperature, but in both the end portions, the recrystallization was found to remain imcomplete or did not occur of all at room temperature.View full abstractDownload PDF (956K) -
Tokutaro Hirone, Kazuo Kamigaki1957 Volume 21 Issue 4 Pages 245-248
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe ultrasonic attenuation coefficients in stainless steel were measured in the frequency range from 0.5 to 6 Mc/s. The stainless steel used here contained about 19 percent of chromium and 10 percent of nickel and had austenite structure at room temperature. The effect of austenite grain size on ultrasonic attenuation was examined. Specimens of various grain sizes were prepared by applying high temperature heat-treatments. The attenuation coefficient increases steeply with frequency and the main part of this attenuation is explained as Rayleigh scattering of ultrasound by austenite grains. The predominant factor determining the magnitude of this scattering is the degree of elastic anisotropy in austenite grains. The value of this anisotropy obtained here in stainless steel is about a hundredfold larger than that of aluminium.View full abstractDownload PDF (548K) -
Masazô Okamoto, Renpei Yoda1957 Volume 21 Issue 4 Pages 249-252
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe principal factors are (i) the kind of inoculants, (ii) the size of inoculants and the addition-method, (iii) the time and the temperature at inoculation, and (iv) the relation between the temperature of Mg-treatment and that of inoculation. The factors (i) and (ii) were already described in the previous reports. The object of the present paper is to explain the influence of time and temperature at both Si-inoculation and Mg-treatment on the inoculation by measuring the rate of spherulitic graphitization of ironc. The effects of the abovementioned principal factors are summarized as follows : (1) Inoculants like Ca-Si are inadequate for the inoculation against strongly deoxidized iron such as Mg-treated one. (2) The inoculating effect is found to be best when the size of inoculants is moderate and the addition-method is appropriate to attain uniform action of the inoculants throughout the molten iron. (3) The rate of spherulitic graphitization of iron inoculated with Si after Mg-treatment is inferior to that of iron inoculated with Si before Mg-treatment. The phenomenon is attributed to the fact that Si in molten iron inoculated after Mg-treatment is hardly consumed for the deoxidation of molten iron and the inoculant becomes more effective. (4) Mg-treatment at high temperature followed by Si-inoculation at low temperature results in good inoculating effect of Si against Mg-treated iron. It signifies that high temperature of Mg-treatment causes the decrease of the amount of residual Mg in molten iron,and low temperature of Si-inoculation brings about steep concentration gradient of local hypereutectic domains in such a melt.View full abstractDownload PDF (760K) -
Kenjirô Ôkawara1957 Volume 21 Issue 4 Pages 252-256
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe author has studied on the secondary recrystallization of Al polycrystal with the purities of 99.996% and 99.6% comparing the results with those of Al single crystals. The following results were obtained: (1) The coarsening did not occur in 99.996%Al, but it occured, in 99.6%Al at a certain range of rolling reduction, which seemed to be the higher the thickness of specimen was the larger, that is, the range was30∼50%in 0.4 mm, 40∼50% in 1 mm, 40∼60% in 5 mm and 70∼95% reduction in 10 mm thickness. (2) Even in the case of specimens cross-rolled or preheated at a lower temperature than 600° after rolling, the coarsening range of rolling reduction was almost unchanged. (3) The coarsening temperature of 1 mm thickness specimen was 600° in 40% red., 590° in 50% red. and 580° in 60% red and for 10 mm thickness specimen it was about 550° in 95% red., but it was 490°, in the 96% rolled specimens sampled from commercial products. (4) The orientations of secondarily recrystallized grain were for the most part nearly (111) or (100), regardless of the rolling method or the heat treatment.View full abstractDownload PDF (811K) -
Kazumasa Futakawa, Kunio Okabayashi1957 Volume 21 Issue 4 Pages 256-259
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of carbon on graphitization of white cast iron was investigated by varying carbon content to 2.15,2.63 and 2.96% in specimens with the silicon content. fixed at 1.3%. The process of the first stage of graphitization was shown by a dilation-time curve, and that of the second stage of graphitization by tan isothermal transformation diagram. Furthermore, the second stage of graphitization was divided into two phases, namely the direct and the indirect transformations. The results obtained were as follows: (1) The time required for the completion of the first stage of graphitization was the shortest in the case of iron containing 2.63% of carbon, and was the longest in the case of iron containing 2.96% of carbon. (2) In both the direct and the indirect transformations, the time required for the completion of the second stage of graphitization was shortened with increasing contents of cabon. (3) The temperature range, which the indirect transformation made the time required for the completion of graphitization shorter than in the case of the direct, was determined for each specimen used in this work.View full abstractDownload PDF (668K) -
Hirosi Amano1957 Volume 21 Issue 4 Pages 260-263
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe methods of determination of zirconium in steels were studied using the radioactive isotope zirconium-95 as a tracer. Experiments were carried out on the determination of zirconium by the phosphate method, arsenate method, basic selenite method and mandelate method, and on the separation of zirconium from iron by means of mercury cathode electrolysis and ion exchange. From the experimental results, it was recommended to precipitate zirconium as its phosphate after the separation from iron by means of mercury cathode electrolysis.View full abstractDownload PDF (603K) -
Toshio Honma1957 Volume 21 Issue 4 Pages 263-267
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe characteristics of Umklapp transformation in Fe-Ni alloy containing 31%Ni were clarified through various experiments. (1) The Umklapp process is characterized by a burst phenomenon. (2) Great kinetic energy accompanied by the umklapp process can make a martensite leaf propagate into a temperature range higher than the usual γ→α transformation temperature in a single crystal with temperature gradient. (3) The 1st burst temperature is scattered statistically in a wide range of temperature. (4) The transformation amounts produced by the 1st burst increases with the degree of supercooling.View full abstractDownload PDF (764K) -
Shôsuke Imoto, Genjirô Mima1957 Volume 21 Issue 4 Pages 267-271
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (565K) -
Saburô Shimodaira, Yoshinobu Sawada1957 Volume 21 Issue 4 Pages 271-275
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrochemical behavior of chromium and tungsten carbides have been studied in sulfuric and hydrochloric acid solutions. Chromium carbide Cr3C2 is fairly stable to oxydizing or reducing actions in acids. Tungsten carbide WC is also stable in acids, but not so much as chromium carbide.View full abstractDownload PDF (384K) -
Shuzo Takeda, Natsuo Yukawa1957 Volume 21 Issue 4 Pages 275-279
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBy means of microscopic observation as well as thermal and X-ray analyses, the constitution of the Cr-Mo-Fe system was investigated, and its equilibrium diagram was determined. In this system, there exist 6 phases,that is, α (b.c.c.), γ (f.c.c.), ε (Fe3Mo2, hexagonal), σ (FeMo & FeCr, tetragonal), δ (high temperature modification of Cr, f.c.c.) and a ternary compound χ (Fe36Mo10Cr12,b.c.c.); and there take place 3 non-variant reactions, Melt(M1)+σ+ε→χ(1455°), Melt(M2)+σ→α+χ(1385°) and Melt(M3)→α+χ+ε(1345°).View full abstractDownload PDF (838K) -
Hideo Takaki, Masashige Koyama, Hidekiyo Fujihira1957 Volume 21 Issue 4 Pages 279-282
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn examination was carried out microscopically and X-ray analytically with single crystals of 99.87% and 99.995% pure tin, in order to clarify the relation between the temperature gradient and the substructures (corrugations and striations) which had been observed in single crystals of tin grown from the melt. The features obtained by increasing the temperature gradient from 13°C/cm to 45°/cm, are summarized as follows: (1) The direction of corrugations inclines steeply from the C rection of easy growth, [110], towards that of the specimen axis. (2) The striations are easy to generate. (3) On the free top surface of the single crystals of 99.87% pure tin grown in the [100] direction, the same step structure as observed in single crystals of 99.995% pure tin at 13°C/cm is also generated.View full abstractDownload PDF (763K) -
Mikio Yamamoto1957 Volume 21 Issue 4 Pages 283-286
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is shown that etch pits on a crystal may originate from the following two causes. One is a microscopic pit or an easily soluble minute portion or inclusion which exists accidentally and locally on the crystal surface, and the other is a dislocation existing in the crystal. In an etch pit of the first kind its depth is unchanged but its calibre increases as the dissolution or etching proceeds (the temporary etch pit), while both the depth and the calibre of an etch pit of the second kind increase in proportion to the etching time (the permanent or proper etch pit). A brief consideration is also made of the multiplicated etch pit as a variation of the permanent etch pit. Experimental evidences for the conclusions are presented.View full abstractDownload PDF (790K) -
Study of a High Temperature Materials (3rd Report). On the Sintering Process of Cr3C2 and Ni PowdersKazuhiko Ogawa, Tamotsu Fukatsu1957 Volume 21 Issue 4 Pages 286-290
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe sintering process of carbide and metal powders has been studied by means of metallographical or X-ray diffraction methods. In this investigation, however, the magnetic properties (saturation magnetization and Curie temperature) were measured to reveal a sintering mechanism of Cr3C2 and Ni powders. The main results were as follows : (1) It is observed that there are four stages in the sintering process. In the first stage, article-bonds were not yet formed, but the surface diffusion of chromium atoms into nickel powders occurred. In the second stage, this diffusion process being rapidly promoted, the bonding between adjacent powders starts. After this diffusion process is nearly finished,in the third stage, a rapid densification occurred due to formation of a liquid phase at the eutectic temperature. And then, in the final fourth stage, a remarkable grain growth of Cr3C2 is observed. (2) The structure of the binder phase is a solid solution of Ni-Cr alloys, where the concentration of Cr is changed according to the condition of sintering.View full abstractDownload PDF (921K) -
Ryoji Watanabe, Shigeyasu Kôda1957 Volume 21 Issue 4 Pages 290-293
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe grain boundary reaction phenomena were microscopically studied on Zn-Cu and Zn-Ag alloys containing 2%Cu and 5%Ag respectively, which were aged at 100°, 125°,200° and 250° after being quenched from the temperature of a uniform solid solution. The results obtained were as follows: (1) The nodules of both alloys are the migrating parts of the grains which were formed from the adjacent grains as a nucleus. (2) The nodule which seems to begin from a point of the boundary (Photo. 1) is often a united one of the nodules which start from many points of the boundary. (3) The rate of growth of nodules increases with the increase of the aging temperature, as shown in the isothermal curves (Fig. 5,6). However, as the general precipitates grow to a visible size, the growth of the nodules is arrested. (4) The activation energies of the grain boundary reaction calculated from Fig. 7 and 8 are 13,000 cal/mol for Zn-Cu, and 13,200 cal/mol for Zn-Ag.View full abstractDownload PDF (758K) -
Yûki Shirakawa1957 Volume 21 Issue 4 Pages 294-296
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe ballistic demagnetizing factor of cylindrical rods of ferromagnetic substances, whose dimension ratio is smaller than 10, was experimentally determined by a new method using the demagnetizing curve of New K.S. Magnet alloy having a large coercive force. The relationship between the demagnetizing factor N and the dimension ratio m may be expressed as follows: N=5.5(m-0.54)^-1.4, m<10.View full abstractDownload PDF (475K) -
Kôji Sanbongi, Yasuo Ohmori1957 Volume 21 Issue 4 Pages 296-300
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe following concentration cell: Fe-Si|CaO-SiO-(Al2O3) (I)|O2|CaO-SiO2-Al2O3 (II)|Fe-Si with ferrosilicon electrodes containing 42%Si was studied at 1,630° Plotting the e.m.f. obtained on the CaO-SiO system against the wt%SiO2, to the reference slag: CaO 45.2 wt%, SiO2 2.2 wt%. Al2O3 53.7 wt%, the curve was characterized by a break which corresponds to CaO. SiO2 composition. The activity of SiO2 on the system CaO-SiO2 was calculated from the e.m.f. by the following equation: −E=RT⁄4FlnSiO2, and the value was compared with the data reported in literatures. Further, iso-activity lines that correspond to the iso-baritic ones observed in the system CaO-SiO-AlO showed considerably complicated figures which might be responsible for the behaviors of Al2O3 in the slags. From this investigaten, it is supposed that the most probable anion species of silica in the studied slags would be SiO44− and SO32−.View full abstractDownload PDF (595K) -
Masayuki Kawasaki, Tadashi Ichiyama1957 Volume 21 Issue 4 Pages 300-304
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSObservations were made on the cleavage cracks produced in polycrystalline zinc by thermal cycles between room temperature and −196°. Cleavages are apt to begin in the vicinity of the grain boundaries. The cracks cannot continue to propagate on a cleavage plane, but jump from one cleavage plane into the adjacent one after propagating for a small distance. Therefore, the cracks are composed of small cracks in a row. These small cracks are linked up by cleavages on (10\={1}0) planes. The cracks propagate across grains and grain boundaries. Thus, polycrystalline zinc may fracture by thermal cycles. The dislocation model of cleavage crack formation involving the concept of piled-up groups of dislocations is considered, and the decrease of fracture strength of polycrystalline zinc with temperature is explained by this model.View full abstractDownload PDF (816K) -
Kichizô Niwa1957 Volume 21 Issue 4 Pages 304-308
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA Simple radioactive tracer technique, which had been used in the previous work(1), was improved to measure more accurately the diffusion coefficient of calcium ion in molten lime-silica-alumina slags of three kinds of compositions over the range of temperatures between 1350° and 1450°. In a slag of 43 pct CaO-39 pct SiO2-18 pct Al2O3, the activation energy of diffusion of calcium ion is calculated as 30±15 kcal.View full abstractDownload PDF (710K)
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