All issues
Volume 21, Issue 10
Displaying 1-15 of 15 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tatsuo Fujiwara1957 Volume 21 Issue 10 Pages 573-576
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBy the author’s previous research,it has been found that the parts of fiber structure corresponding to the boundaries of primary crystals give aid to formation and propagation of heat-checks. As these fiber structures are affected by the forging ratio, their effect on heat-checking was studied in the same method as in the previous report, and the results obtained are as follows: (1) In proportion to the increase of the forging ratio, the total number(n) and the total depth (L) of the checks decrease, but the max.depth (lmax) and the mean depth (L⁄n) change scarcely. In the present case, n,L and their decreasing rate corresponding to the forging ratio are larger when the checks appear in parallel to the direction of the fibres than when perpendicular. (2) The influence of the forging ratio on heat-checking is found similarly also on the specimen sampled from the core part of billets, but their properties is somewhat inferior to the outside part, as far as heat-checking concerns. (3) Homogenized and upset specimens have little directional properties on heat-checking and have better properties than that of ordinary forged one in the case of the same real forging ratio. (4) The above mentioned results could interpreted by the microstructure of the specimen.View full abstractDownload PDF (1059K) -
Takao Honjo1957 Volume 21 Issue 10 Pages 577-579
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStudying the titration of lead, the author found a simple and rapid method for the estimation of lead in various alloys. Dissolving the alloy in HNO3, excess NaOH was then added until the produced Pb(OH)2 was dissolved again. Lead was precipitated in the form of basic lead carbonate by passing CO2 through the alkaline solution. The precipitate was filtered and washed with 1%KNO3 solution. The basic lead carbonate, thus obtained, was dissolved in a definite amount of N/20 HNO3 solution. The excess HNO3 was successfully titrated with N/20 NaOH solution, using methylorange as indicator. Phenolphthalein cannot be used, for Pb(OH)2 begins to precipitate at about pH 5.4. The method proves to be useful in analysing alloys containing lead, such as bronze, soft solder, and type metal.View full abstractDownload PDF (449K) -
Mayumi Someno, Toshimasa Aoki1957 Volume 21 Issue 10 Pages 579-583
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMolybdenum can berenderd highly resitsant to oxidation by treatment with a hydrogen-silicon tetrachloride atomosphere so as to produce a molybdenum disilicide coating on its surface. The effects of time, temperature and concentration of silicon tetrachloride on the rate of reaction were investigated at 1000∼1800°. By treating a powder mixture of silicon and molybdenum (in the stoichiometric ratio of MoSi2) either in hydrogen or in silicon tetrachloride atmosphere, the formation of molybdenum disilicide was observable only at the high temperature of 1300° in the former, but at a lower temperature as 1000° in the latter atmosphere. The mechanism of the reaction between molybdenum and silicon tetrachloride, and the process of sintering of molybdenum-silicon powder was interpreted by the formation of silicon dichloride at high temperature.View full abstractDownload PDF (669K) -
Toichi Watanabe, Jiro Saga1957 Volume 21 Issue 10 Pages 583-587
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanical properties of two 18-8 type stainless steel wires were studied. Steel A contained 0.056%C, 0.039%N, 8.02%Ni, 16.77%Cr, while steel C 0.060%C, 0.033%N, 9.91%Ni, 18.80%Cr. The variations of the proportional limit and the yield point due to cold drawing and subsequent annealing were mainly investigated. The following conclusions may be drawn from the experimental results : (a) The steel A can be transformed nearly 100% into α phase only by drawing at room temperature. The γ→α transformation occurs most remarkably in the range of about 40∼60% reduction, and takes place in the interior earlier than the exterior of the wire, while in steel C, the transformation is no more than 20% by drawing of 90% reduction. (b) Although the Vickers hardness (Hv) and the tensile strength (σB) increase with the increase of rate of drawing in both steels, the proportional limit (σP) does not. σP of cold-drawn wires, therefore, is very low in spite of their high Hv and σB. For steel C, this is more remarkable, and its σP is independent of the degree of cold working ranging from about 20 to 90% reduction. (c) The hardening by annealing after cold drawing proceeds in two stages: at the temperatures of 200° and 400° for steel A, and 250° and 450∼550° for steel C. (d) Annealing after cold drawing is very effective for increasing σP, the effect being more pronounced in steel A in a highly cold drawn state. For example, σP is 120 kg/mm2 for steel A and 50 kg/mm2 for steel C, when they are cold drawn about 60% in reduction of area and annealed for 1/2 hr at 400° and 450° respectively.View full abstractDownload PDF (676K) -
Taro Ohtsuki1957 Volume 21 Issue 10 Pages 587-589
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe results show that (1) the gas evolved from copper manufactured by deoxidizing with hydrogen consists mainly in H2 over the temperature range 860° to 960° and the diffusion coefficient of H2 in copper is represented by the relation D=2×10−3exp(−15,000⁄RT) cm2·sec−1. (2) the gas evolved from copper manufactured by deoxidizing with magnesium consists mainly in H2, with smaller amounts of CO, CO2 and H2O at the temperature 610∼975° and the relation between the quantity of gas and temperature is at random, because magnesium included in copper diffuses and evaporates on heating in vacuum and cleaning action of the gas evolved from copper by a part of the magnesium content takes place.View full abstractDownload PDF (284K) -
Akira Takaoki1957 Volume 21 Issue 10 Pages 589-593
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSince 1952, it has been found at our steel works that residual stress in heat-treated steels has an enormous influence upon ultrasonic wave attenuation. Therefore the attenuation by residual stresses in steels has been studied by pulsed reflection method. The specimens of 0.38%C-steel of the size of 70 mm D×280 mm were heat-treated at various temperatures. Ultrasonic waves of the frequency range of 1 to 5 megacycles were used for the attenuation measurements on the axial direction of them and the residual stress were measured by Sachs’s boring-out method. The results obtained were as follows : (1)By water quenching from 700° the attenuation decreases at the center and increases severely at the circumference of the specimen and the maximum attenuation point is found between them. (2) A change in the ultrasonic wave attenuation appears by the residual stress when the specimens are quenched in water from the temperatures of 200∼700°. (3) Another change appears by stress relieving when the quenched specimens are heated at the temperatures of 200∼700°.View full abstractDownload PDF (630K) -
Akira Takaoki1957 Volume 21 Issue 10 Pages 593-597
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt was described in the first report that the attenuation of ultrasonic waves in steel was influenced extraordinarily by thermal stresses. In this report the change of ultrasonic attenuation by the tensile stress on tension test is studied. Pulsed waves of 3 megacycles were used under reflection method and 0.21∼0.26%C-steel and 25-20 stainless steel for the measurements. The results are summarized as follows: (1)The attenuation curve by tensile stress corresponds to the stress-strain diagram but the change is very small. (2) There seems to be a little decrease in the attenuation in ferritic steel but no effect on 25-20 stainless steel due to the tensile stress within the elastic limit. (3) The attenuation in plastic deformed steels increases by tensile stress. (4)The same phenomena are observed in the direction and at right angle to the principal stress.View full abstractDownload PDF (623K) -
Yoshiki Ogawa, Yoshihiro Hisamatsu, Kazutaka Kawamura1957 Volume 21 Issue 10 Pages 597-599
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA method for preparing protective coating on mild steel has been dealt with. The principle lies in that titanium can be deposited on a steel sheet when it is immersed side by side with a titanium sheet or titanium powder in a fused-salt bath consisting of NaCl, KCl or NaCl-KCl mixture. The thickness of the coating obtained depends mainly on temperature and time but not on the initial bath composition. Pyrosol of titanium may have been produced during the process. The microvickers hardness of the titanium coating has been found to be 400∼600 and a salt spray test has revealed high corrosion resistivity.View full abstractDownload PDF (423K) -
Yoshiki Ogawa, Yoshihiro Hisamatsu, Kazutaka Kawamura, Junji Tatsuma1957 Volume 21 Issue 10 Pages 599-602
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn this paper another method of preparing a protective titanium coating on mild steel has been dealt with. The procedure consists of electrolyzing potassium titanium fluoride dissolved in potassium and sodium chloride under an inert, i.e. argon atmosphere. Electrolytic cell is made of a graphite crucible with a diameter of 8 cm and a depth of 20 cm, of which the outer surface is protected by 18-8 stainless steel casing from atmospheric oxidation. Better titanium coatings were obtained by using modulated current (D.C.partially interrupted at the rate of 3 times a second) than in the case of plain D.C.
Consistently good results were obtained under following condition:
(This article is not displayable. Please see full text pdf.)
The coating has been found to be softer than in the case of pyrosol method, the microvickers hardness being ca. 300. Salt spray tests have shown a corrosion resistivity of the coating as high as in the case of the pyrosol method.View full abstractDownload PDF (554K) -
Tôichi Watanabe, Jirô Saga1957 Volume 21 Issue 10 Pages 602-606
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSVariation of mechanical properties due to cold drawing and subsequent annealing was studied. The materials used in this investigation were three kinds of austenitic stainless steels, containing about 10% nickel and 0.03, 0.06, 0.08% carbon respectively. The following conclusions may be drawn from the experimental results. (1) The following empirical equations describe the relationships among the Vickers hardness (Hv), the tensile strength (σB·kg/mm2) and the yield point (0.2% set) (σy0.2·kg/mm2).
(This article is not displayable. Please see full text pdf.)
(2) The proportional limit of cold drawn wires is very low in spite of their high Hv and σB,and independent of both the degree of cold drawing ranging from 20 to 90% reduction of area and the carbon content ranging from 0.03 to 0.08% in weight. (3) Annealing after cold drawing is very effective for increasing the proportional limit. For example, the proportional limit is about 15 kg/mm2 when they are cold drawn, and about 50 kg/mm2 when they are annealed for 1/2 hr at 400° after cold drawing. The proportional limit of stainless steel wire,cold drawn and subsequently annealed,is also independent of both the degree of cold drawing ranging from 20 to 90% reduction of area and the carbon content ranging from 0.03 to 0.08% in weight.View full abstractDownload PDF (517K) -
Hiroshi Fujita, Zenji Nishiyama1957 Volume 21 Issue 10 Pages 607-611
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSElectron-microscopic observation has been made of the subgrains formed in cold-worked aluminium with the following results : (1) The prominent slip bands (S-bands) have the character of subboundaries, forming subgrains bounded by them, (2) the S-bands also form the subgrain in conjunction with deformation bands, (3) a further refinement of the subgrain, to the size smaller than one micron, occurs mainly by formation of small kink bands (K-bands), and (4) the final size of the subgrain is independent of the grain size before working.View full abstractDownload PDF (1338K) -
Toshio Abe1957 Volume 21 Issue 10 Pages 611-614
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe distribution of minute impurities in the molten metal near the solid-melt interface that determines the concentration of impurities in the solidified metal may be affected largely by the convective flow of the melt.C.Wagner has treated the same subject, with the assumption that such a type of flow is caused by the difference of local concentrations in the melt. However, in the case of ordinary zone melting where the travelling resistance furnace is used, it is expected that natural convection caused by the local temperature difference will rather predominate. Therefore, with the model of natural convective flow due to thermal gradient perpendicular to the vertical solid-melt interface, the author discusses the distribution of impurity concentration near the interface and derives the effective distribution coefficient as a function of the solidification rate and the distance measured downward from the free surface. The results are in good agreement with the values measured with Sb-doped germanium single crystals grown parallel to the ⟨111⟩ axis by zone leveling method.View full abstractDownload PDF (626K) -
Takeshi Akutagawa, Toyoaki Bada1957 Volume 21 Issue 10 Pages 614-618
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUsing a hot-stage microscope with cinecamera, the kinetics of β-α transformation of titanium was observed by means of the surface relief associated with the martensitic transformation, especially the effect of the rate of cooling. on the β-α transformation of titanium was studied. When the rate of cooling was below 20°C/min, the kinetics of the transformation showed the following results:-(1)The growth rate of α needles was proportional to the rate of cooling, and increased with the increasing rate of cooling. (2) The maximum height of surface relief of α needles was inversely proportional to the rate of cooling, and decreased with the increasing rate of cooling.(3) The grain size of α crystal decreased and the its hardness increased with increasing rate of cooling. However, the increase of hardness was saturated at the rate of cooling of 20°C/min. (4) The Ms point was 885°, the Mf point was 860° and the range of transformation temperature was 25°. (5) The β-α transformation of titanium was athermal martensitic transformation and the kinetics of the transformation was the nucleation and growth process, i.e.the “Schiebung” martensitic transformation.View full abstractDownload PDF (824K) -
Keisuke Matsuura, Ryukichi Nagasaki, Shigeyasu Kôda1957 Volume 21 Issue 10 Pages 618-621
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTo clarify the mechanism of precipitation hardening in aluminium-copper alloys containing 4%Cu, we examined mainly the changes in the stress-strain curves and in the resistivity-strain curves following aging at 240°, 200° and 160°. These results show that some differences exist between the mechanism of hardening at aging temperatures above 200° and at 160°. Such differences may be ascribed to that in the effect of the decomposition products which exist at each aging temperature, i.e., the G-P zone and the θ′ phase on the movement of dislocations. Also, the data of resistivity-strain curves show that the resistivity increases appreciably by the plastic deformation at the early stage in aging more than in an over-aged state. This is consistent with the results obtained by X-ray methods by Guinier,i.e.such an increase in resistivity in the early stage is ascribed to the formation of small G-P(I) during plastic deformation.View full abstractDownload PDF (553K) -
Toshimasa Morooka1957 Volume 21 Issue 10 Pages 621-624
Published: 1957
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe Young’s modulus (E) of variously heat-treated alloys containing 11.6%Al was measured by longitudinal vibration method at room temperature. The specimen containing much martensite by quenching showed very low Young’s modulus. On tempering, however, it showed various different Young’s moduli according to the tempering temperatures and the rates of cooling from those temperatures. The tempering reaction is very active at temperatures above 350° but not below 300°. On tempering at above 400°, the alloy finally showed very high Young’s modulus, and the tempering curve, which E on the ordinate and the tempering duration on the abscissa, showed a maximum and a minimum values in the initial range. On tempering at just 400°, after passing this maximum and minimum E increased rapidly to the saturation value. On tempering at above 500°, the maximum was missing and after passing the minimum E increased rapidly to the saturation value. These phenomena were explained as follows : The increase of E up to the maximum (at the begining) is due to the release of quenching stress in martensite (β′). The next decrease of E up to the minimum is due to the change of residual structure into martensite. The final increase of E up to the saturation value is due to the decomposition of martensite into pearlite.View full abstractDownload PDF (801K)
- |<
- <
- 1
- >
- >|