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Volume 34, Issue 2
Displaying 1-23 of 23 articles from this issue
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Masuzo Ueda, Fumio Seki, Kazuo Hosokawa1970 Volume 34 Issue 2 Pages 127-132
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSX-ray diffraction and fluorescent X-ray analysis were carried out to clarify the reactions between fluxes and a steel plate or a molten lead and between the behaviour of zinc or tin and its alloy layers on steel plates in a molten lead. The results may be summarized as follows.
(1) Except the molten SnCl2 flux, no metal ions were detected as deposit ions on a steel plate.
(2) The metal ions contained in the fluxes were mostly present in the slag and partly transformed into oxides. No metal ions were detected in the lead film and the Fe-Pb intermediate layer on a steel plate, and also in the lead bath.
(3) As the steel plate coated with Sn or Zn was dipped into molten lead, either Sn and Fe-Sn alloy layers or Zn and Fe-Zn alloy layers dissolved once, and then the lead film was formed. Namely the layers were not detected between the matrix and the lead film.
(4) In case of the Pb-Sn or the Pb-Zn alloy bath, the diffusion of Sn or Zn was very slow.View full abstractDownload PDF (1161K) -
Ryosuke Hasegawa, Toshio Kurosawa, Tetsuo Yagihashi1970 Volume 34 Issue 2 Pages 132-137
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHydrogen reduction of germanium dioxide was studied by means of a thermobalance in pure hydrogen, a mixture of hydrogen and argon, and cracked ammonia gas. The initiation temperature was about 450°C and sublimation of GeO was increased remarkably above 650°C. The reduction curves were the sigmoid type characteristic of the auto-catalytic reaction.
The incubation time was shortened with increase in temperature and partial pressure of hydrogen. In the main reduction period ranging about 10 to 90%, the formula of interface reaction {1−(1−R)1⁄3}=Kt could be applied and the activation energy was 18.4 kcal/mol. According to the dimentionless time analysis, the effect of gas diffusion through the product layer was found to be added in the final period. A linear relation was obtained between reduction rate and partial pressure of hydrogen, and a slower reaction rate was found in cracked ammonia gas than in the mixture of hydrogen and argon.
Furthermore, the experimental result was discussed according to the Eyring theory, and good agreement was obtained.View full abstractDownload PDF (2229K) -
Kinya Tsuchiya, Terutaka Tamai, Hirohiko Terui1970 Volume 34 Issue 2 Pages 138-144
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecious metal contact materials were plated on the surface of base metals such as Cu, Ni and 18-8 Stainless steel by the spark-deposition method, and some physical properties of the spark-deposited layers such as hardness, thickness, surface roughness and microstructure were investigated. Moreover, we studied some of the contact performance characteristics, such as static contact resistance, change of contact resistance with exposure time in a corrosive gas environment, and dynamic contact resistance at make-and-break contacts. The following results were obtained. The circuit conditions of the spark-deposition method did not affect these physical properties so much. The microstructure of the spark-deposited surface was best when Cu was used as a substrate material. The hardness of the spark-deposited precious metal was greater than that of solid precious metals. The thickness of the spark-deposited layers was found to be the same as that of the plated contacts. The specimens with layers of fine structure and substrates of high conductivity gave rise to a low and steady static contact resistance in a corrosive gas environment as well as in normal atmosphere. Although the surface of the spark-deposited layers was uneven, its static contact resistance became smaller and more stable by alumina-polishing. In the make-and-break test with low currents, it also showed a low contact resistance. Consequently, it can be said that spark-deposited precious metals are at least as good as plated precious metals contacts. Contacts can be more easily rejuvenated by the spark-deposition method and there is a good possibility that they can be manufactured more easily and economically by this method.View full abstractDownload PDF (1832K) -
Toru Yukawa, Shitoshi Ôtani, Takeo Sakai1970 Volume 34 Issue 2 Pages 145-149
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEmbrittlement of Ti-8Al alloy due to the ordered phase precipitated during aging was studied by means of the tensile and impact test, the hardness test, and optical and transmission microscopy. The dimensional change due to precipitation of the order phase during isothermal transformation was also investigated using an automatic transformation testing apparatus, “Formastor-F”.
Ti-8Al alloys aged at 500°∼650°C were embrittled within 10 hr, while Ti-5Al alloys aged at the same temperatures up to 1000 hr were not. But transmission electron microscopy revealed the precipitation of α2-phase particles in Ti-8Al alloy aged for 1000 hr. The contraction due to the precipitation of α2-phase particles during isothermal transformation began within 1 min after quenching and continued up to 2∼5 hr. The contraction showed a peak at 500°C and was negligibly small over 700°C.View full abstractDownload PDF (1436K) -
Hideo Abe, Kazumasa Togano1970 Volume 34 Issue 2 Pages 149-154
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is very interesting technologically to control the texture of industrial material, for which the texture of the ingot has a practical importance. In the present study, ingots of Al, Al-3%Cu alloy and Zn-1.5%Cd alloy, in which the orientations of all the crystal grains were aligned three-dimensionally, were produced by casting into double-orientation molds. The textures are represented by stereographic pole figures projected on the plane vertical to the second growth direction. In pure Al and Al-3%Cu alloy (F.C.C. structure), when the growth direction was changed by 90° at an adequate distance from the chill plate, the columnar crystals in the second growth region were aligned in the (100)[001] orientation. In Al-3%Cu alloy, when the growth direction was changed by 45°, the preferred orientation in the initial part of the second growth region was near (10\bar1)[101], but as the secondary growth proceeded, the (100)[001] orientation set in to mingle. In Zn-1.5%Cd alloy (H.C.P. structure), when the growth direction was changed by 60°, the texture with a sharp (\bar1010)[\bar12\bar10] orientation was developed.View full abstractDownload PDF (1597K) -
Isao Gokyu, Teruo Kishi, Hikaru Wada1970 Volume 34 Issue 2 Pages 154-160
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of pre-strain and grain-size on the Bauschinger effect was measured, with thin pipes of Cu, α-Brass and mild-steel using the reversible twist machine.
The results are as follows:
(1) The Bauschinger effect increases seemingly with increase in pre-strain, while, the ratio of the Bauschinger effect to the amount of strain hardening decreases in proportion to the amount of pre-strain. At the critical pre-strain, where the Bauschinger effect decreases suddenly, the stress-strain curves of polycrystals are divided into two regions similar to stage I and stage II of single crystals.
(2) The Bauschinger effect of the metal with lower stacking fault energy (α-Brass) is larger than that with higher stacking fault energy (Cu). Consequently, from the hardness change with reverse strain and calculation of the stress required to contract partial dislocations, it is reasonable to conclude that the Bauschinger effect is controlled directly by the amount of piled-up dislocations against the obstacles.
(3) Using the measured data on the Bauschinger effect, it is possible to divide the stress-strain curves of polycrystals into the three regions corresponding to the three stages of single crystals.
(4) The finer the grain-size, the larger the Bauschinger effect. With increasing pre-strain, the grain-size dependence of α-Brass and Cu becomes smaller, excepting mild-steel.View full abstractDownload PDF (2332K) -
Isao Gokyu, Teruo Kishi1970 Volume 34 Issue 2 Pages 161-165
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe decrease of yield stress (0.1% proof stress) due to the Bauschinger effect was measured by the torsion test at room temperature, using thin pipes of Cu, α-Brass, iron-steel, Ti, Zr and Mg.
In the case of pre-straining γ and unloading, the yield stress is τF for the forward direction and τR for the reverse direction. Then, the decrease of yield stress is τB=τF−|τR| (called the Bauschinger stress).
The authors found a new relation between pre-strain γ and Bauschinger stress τB.
The results are as follows:
(1) The following relation was found experimentally:
(This article is not displayable. Please see full text pdf.)
where k and m are constants characteristic of materials, which are controlled by grain-size and metallurgical structure. In the case of the absence of the Bauschinger effect, k=0.
(2) Extending the above equation, the yield condition under a multi-axis stress, including the Bauschinger effect, was newly obtained as follows:
(This article is not displayable. Please see full text pdf.)
f: plastisity potential, J2: second-order stress invariant, εij and σij: components of strain and stress tensor, K0: shear yield stress. Here, εijm is the same in sign as εij and its absolute value is the m-th power of εij. The above equation is reasonable because it includes the strain history and the first-order term of stress, and because additional term k·εijm·σij has the dimension of energy.View full abstractDownload PDF (579K) -
Hiroyasu Mitani, Hiroshi Nagai, Takeshi Ohtani1970 Volume 34 Issue 2 Pages 165-170
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA new process utilizing the subhalide reaction for refining of aluminum from crude aluminum alloys is a subject of increasing concern. In this process, the ternary Al-Si-Fe alloy containing various amounts of silicon and iron which is produced by the direct reduction of Bauxite or alumina-bearing ores is used as the raw material. Therefore, on selecting the raw material composition suitable to this process, it is very important to know the thermodynamic properties of the ternary Al-Si-Fe system. However, very little work has been reported about them.
In this report, the activities of Al in the ternary liquid Al-Si-Fe system were determined by e.m.f. measurements of the reversible concentration cell
(This article is not displayable. Please see full text pdf.)
in the range 750°∼1100°C.
Using the obtained activities of Al, the activities of Si and Fe at 1000°C were calculated by Schuhmann’s tangent intercept procedure.
Judging from the obtained activities of Al, Si and Fe, it was concluded that the liquid Al-Si-Fe alloy with Fe⁄Si=1.5 is most suitable to this process as the raw material.View full abstractDownload PDF (1220K) -
Hajime Suto, Toru Imai, Teruo Uno1970 Volume 34 Issue 2 Pages 171-177
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn aid of the study on heat resisting steels, the internal friction of iron and iron-chromium and iron-molybdenum alloys was investigated. The results obtained are as follows:
(1) The Q−1−T curve of iron has two peaks at about 500°C and 630°C. (2) The temperature of 500°C-peak rises and the activation energy increases with the carbon content. But the effect of carbon on the temperature for the 630°C-peak is small. (3) Chromium suppresses the 500°C-peak. The temperatures of both peaks do not change remarkably by chromium additions, while the activation energy for the 630°C-peak increases with the chromium content. (4) The temperatures for both peaks, especially the low temperature peak, rise with increasing molybdenum content. And the apparent activation energy of the combined peaks increases remarkably with the molybdenum content. (5) It is considered that the low temperature peak corresponds to the atom movement in the grain boundary layer, and that the high temperature peak to the lattice diffusion. Therefore, the measurement of internal friction is useful to understand the high temperature strength of solid solution alloys.View full abstractDownload PDF (2050K) -
Hajime Suto1970 Volume 34 Issue 2 Pages 177-182
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to obtain a fundamental knowledge for the study of austenitic heat resisting steels, the strengthening factors affecting high temperature creep of nickel-copper alloys, representative of face-centered cubic alloys, is discussed using Sherby’s equation: \dotεs=Aγ3.5(σ⁄E)nD, where \dotεs is the steady state creep rate, γ is the stacking fault energy, σ is the applied stress, E is Young’s modulus, D is a diffusion constant. Although it is shown that the steady state creep rate of these alloys can be expressed approximately with the above equation, it is necessary to consider a third strengthening factor. A possible factor seems to be the friction stress to dislocations, induced by dragging the Suzuki or the Cottrell atmosphere. To ascertain this assumption, the anomalous strengthening by annealing at about 300°C was measured for the 5% cold worked alloy. On the other hand, dislocation structures of the cold worked alloys were continuously observed at elevated temperatures by means of 500 kV electron microscope, and it was confirmed that the dislocation arrangement does not change up to 350°C. This indicates that the anomalous strengthening is due to the segregation of solute atoms to dislocations. From these results, the contributions from the solute segregation to dislocations on the strength are considered to be about 1/5 those estimated by Suzuki. These values support the assumption that the third strengthening factor at high temperature may be the interaction between dislocations and the solute atmosphere.View full abstractDownload PDF (1718K) -
Kozo Kishi, Hiroshi Eda, Yoshio Kitsunai1970 Volume 34 Issue 2 Pages 182-188
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWe compared measured value with calculated value of residual stress in the machined surface layer of the 0.10%C steel test pieces which is subjected to heating by tool and to local heating under the cutting edge; the calculation in this case is based on the assumption that the stress is mechanically and thermally induced.
We also investigated the effect of C-content ranging from 0.10% to 0.97%C on the residual stress of the machined surface and machinability factors; that is cutting force, cutting temperature, surface roughness and chip thickness.
The results obtained are follows:
The distribution stress in the machined surface layer which was calculated as the resultant stress is very close to the value measured by an X-ray diffraction parallel beam type GM counter.
When the carbon content is within the range of 0.20∼0.30%, the cutting force, surface roughness and residual stress on the machined surface shows a minimum value and in steels containing 0.40∼0.60%C shows a maximum value.View full abstractDownload PDF (1911K) -
Tsuyoshi Masumoto, Masaaki Naka, Yûnoshin Imai1970 Volume 34 Issue 2 Pages 188-194
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA high temperature-high pressure equipment having a performance of the maximum condition of 1600°C and 5000 atm was developed, and studies on the absorption of nitrogen in iron and iron alloys such as Fe-C, Fe-Cr, Fe-Mn and Fe-Ni were carried out in the pressure range of 1 to 3300 atm at 1400° and 1550°C. It was observed that the absorbed amount of nitrogen in a solid or liquid metal deviates from a value calculated by Sieverts’ law with increasing pressure.View full abstractDownload PDF (2089K) -
Tsuyoshi Masumoto, Masaaki Naka, Yûnoshin Imai1970 Volume 34 Issue 2 Pages 195-201
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStudies on the equilibrium between austenitic iron and nitrogen under various conditions of the maximum pressure of 920 kg/cm2 and the temperature range of 950°∼1300°C were carried out using a high temperature-high pressure equipment. It was shown that the concentration of nitrogen in austenite deviates from Sieverts’ law with increasing pressure. The cause for such discrepancy was considered thermodynamically and statistically. That is, the experimental result can reasonably be explained from the geometrical consideration that the chemical potential of a nitrogen atom in austenite with a high nitrogen content, departs remarkably from the value for the ideal random interstitial solid solution, since each interstitial atom added excludes other interstitial atoms from the seven adjacent sites. Thus, the activity of nitrogen in austenitic iron can be expressed by the following equations:
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (2080K) -
Kiyoshi Inoue, Kyôji Tachikawa1970 Volume 34 Issue 2 Pages 202-209
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHigh-field characteristics of several kinds of superconducting wires were studied by a pulsed magnet. An electrical energy of 28.3 kJ, stored in a capacitor bank, was transferred to the liquid nitrogen cooled magnet. The i.d. of the magnet was 30 mm and the maximum field produced was 220 kOe with a rise time of 16 msec. The noise due to the induced voltage was canceled by a compensation coil. The transition sensitivity of the measuring system was 0.1 mV.
Resistive critical fields Hr measured by the pulsed magnet with rise times longer than 10 msec were quite consistent with those measured by a steady field magnet. Critical currents Jc of Nb-Zr alloy wires were much decreased by the pulsed fields, whereas in compounds wires, e.g. V3Ga and Nb3Sn, the decreases of Jc were small. Resistivity changes in flux flow states and the peak effect phenomena could also be observed by the pulsed field measurement. The Hr of Nb-Zr alloy wires were increased by the decomposition reaction at 785°C and decreased by the eutectoid reaction at 560°C. V3Ga wires made by a new solid state diffusion process at 600°∼700°C showed higher Jc than those of Nb3Sn above 120 kOe. Hr of V3Ga wires seemed to be around 220 kOe at 4.2°K.View full abstractDownload PDF (2283K) -
Genjiro Mima, Yasuzo Tanaka1970 Volume 34 Issue 2 Pages 209-214
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHardness measurements and electron microscopic observations were employed to study the effects of additions of 0.04 and 0.13 wt% silver on the direct aging and the two-step aging characteristics of Mg-5.5 wt%Zn alloys. The aging processes are changed by the intersection temperatures of 100°C and about 50°C, which are obtained from the C-curves analyzed kinematically, but the silver addition raises these temperatures by 10°∼20°C. The final hardening is due to the genaral precipitation of the transition phase β′ in the form of a long thin rod. This system indicates the quenching rate dependence and effectiveness of the two-step aging; the pre-β′ region in the C-curve diagram gives the optimum condition of pre-aging, and the addition of 0.04 wt% silver is most suitable for these phenomena. Electron microscopic observations show that the silver addition little affects the direct aging, but it accelrates the refinment of the β′ phase in the two-step aging. As regards the direct aging and the two-step aging, it may be concluded that the silver atom plays a significant role as a positive action of nucleation for the pre-β′ or the β′ phase.View full abstractDownload PDF (2134K) -
Keizo Onishi1970 Volume 34 Issue 2 Pages 215-221
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe author et al. reported previously that the hot-rolled steel plate had directionality of hydrogen occlusion. Hydrogen embrittlement in steels has a close relation to the amount of hydrogen occlusion, and hydrogen embrittlement of the steel plate may have some bearing upon this directionality. From this point of view, for the specimens taken from various directions of the weldable high strength steel plate, the relations of directionality of hydrogen occlusion with hydrogen embrittlement, hydrogen diffusion, etc. were investigated. The results obtained are as follows:
(1) The hot-rolled steel plate has directionality in hydrogen occlusion, hydrogen diffusion, and hydrogen embrittlement. That is, the amount of hydrogen occlusion and hydrogen embrittlement of specimen X-Y taken from parallel to the hot-rolled surface are higher than those of specimen X-Z and Y-Z from the direction of plate thickness. The diffusion rate of hydrogen is the highest in the rolling direction, next high in the direction perpendicular to the rolling, and the lowest in the direction of plate thickness.
(2) In the fracture surface of the embrittled specimen, fish eyes which formed parallel to the rolled surface of the steel plate were observed. The facet of the fish eye was quasi cleavage characteristic of hydrogen embrittlement, the others being of ductile fracture.
(3) From these results, heterogeneity of hydrogen occlusion in steels and the mechanism of hydrogen embrittlement were discussed.View full abstractDownload PDF (1917K) -
Sôkichi Umekawa, Kôzô Nakazawa1970 Volume 34 Issue 2 Pages 222-227
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSn-Pb eutectic alloy strengthened by 18-8 stainless steel fibers was studied with special emphasis on a fundamental aspect of fiber reinforced composite materials. The system was employed because the strength, ductility and Young’s modulus of Sn-Pb alloy were very different from those of stainless steel. Mechanical properties of fiber were measured with a variety of annealing temperature, diameter and gage length. The tensile strength and fracture behaviors of the composite material in which the fiber diameter was 161 μ were studied, and the following results were obtained.
(1) In the as-drawn fiber, a tendency that the thinner the diameter the higher the strength is observed. The strength of the fiber, however, is actually independent of its diameter and depends only on its history, while it decreases with decreasing diameter from 30 μ to 2 μ. Increasing of the fiber strength with decreasing gage length is also observed. As the fiber is annealed above 800°C, both the strength and the elongation decrease with decreasing diameter. This may be due to large grains.
(2) The tensile strength of the composite increases linearly with fiber concentration and this agrees with the equation proposed by Kelly. The elongation decreases with increasing fiber concentration. When the fiber-matrix bonding is well established and the volume fraction of the fiber is small, the elongation at a high stress level is large since discontinuous fibers share stress effectively even continuous fibers have been broken randomly into a few discontinuous segments. The distribution of the length of the discontinuous segments is approximately equal to that estimated by the simple model specimens. At a large volume fraction of the fiber, continuous fibers are broken down at one section of the composite and the stress-strain curve is very similar to that of the fiber itself. When the fiber-matrix bonding is not so completely built up, fibers are broken randomly throughout the composite only at one portion, and then the load bearing capacity of the composite drops down to stress level of the matrix.View full abstractDownload PDF (1081K) -
Yasunori Tanji, Yûki Shirakawa1970 Volume 34 Issue 2 Pages 228-232
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe thermal expansion coefficient α was measured over the temperature range from 800°C to room temperature for Fe-Ni (fcc) alloys. The results obtained are as follows: (1) On the temperature vs. α curve, a peak appears at the Curie temperature Tc of the alloys in the composition range above about 42%Ni but disappears in the range of 42∼30%Ni. (2) Tc of the alloys with more than 42%Ni is present in the α phase region higher than the upper critical temperature of the region of a (α+γ) mixture phase in the thermal equilibrium phase diagram. (3) The value of αp obtained by eliminating the magnetic contribution from α shows a minimum in the region of Invar as in the case of α. This may suggest that we must consider an interatomic cohesive force in addition to the magnetic effect to make clear the origin of the Invar property.View full abstractDownload PDF (1677K) -
Toshihiro Kinoshita, Youichi Tokunaga, Hiroyasu Endo1970 Volume 34 Issue 2 Pages 233-238
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSResistivity measurements were carried out on martensitic iron alloys with compositions of 13%Cr-16%Co, 13%Cr-16%Co-4.5%Mo and 13%Cr-8%Ni-4.5%Mo. The results were compared with those obtained from the hardness tests and the specific heat measurement in previous work. The resistivity changes, which is in good agreement with that of the specific heat, may be explained in terms of the appearance and dissolution of the cluster or the rich zone. In addition, these behaviors are scarcely affected by the presence of molybdenum, which is considered as a hardening element. The precise kinetics for the low-temperature aging reactions, however, could not be decided from the isothermal aging data in the temperature range of 375°∼550°C. The reason for this is to be the extremly rapid reaction at an early stage of the aging and a simultaneous occurrence of the diffusion-controlled reaction of the precipitation.
The reversion curve obtained from the experiment can be considered as a resultant combinination of two component curves: a component giving an initial increase in resistivity due to the true reversion, and a component of decreasing resistivity due to the cluster or rich zone formation of solute remaining in the solid solution even after the preaging treatment. The shape of the isothermal aging curves and the reversion behaviors may be explained by considering that the low temperature aging proceeds in a different mechanism, as is seen in the relation between the fast reaction and the slow reaction.
And also, the fast reaction is steadily suppressed by cold work prior to aging. This phenomenon can be reasonably explained by assuming that the excess vacancies in the martensite contribute to the rate-control of the low-temperature aging reactions.View full abstractDownload PDF (1725K) -
Isao Gokyu, Keijiro Suzuki, Chozo Fujikura1970 Volume 34 Issue 2 Pages 239-243
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDrawability of metal sheets is indicated by Swift’s L.D.R., C.C.V. of Fukui’s, and the plastic strain ratio r. Swift’s L.D.R. and C.C.V. of Fukui’s tests are based on the deep drawing test, while the plastic strain ratio r is determined simply by the tensile test. It has been reported by many investigators that these values are excellent indicators of drawability. But it is difficult in practice to indicate the drawability of thin sheets by Fukui’s test and the plastic strain ratio r. On the other hand, Swift’s test is favorable for thin sheets, but in addition to the complexity to determine the L.D.R. of metal sheets, the reproducibility of the value obtained is doubtful.
So in this paper the validity of the load deep drawing method was discussed, where the value is indicated by the ratio of fracture load in the cup wall to the maximum load to deform the flange. Although the fracture load must be kept constant irrespective of the drawing ratio, the observed values are at variance, and therefore L.D.R. of metal sheets cannot be determined by this so-called T.Z.P. method. But it has been found that the fracture loads of the cup wall in various drawing ratios can be kept constant by a suitable lubricating operation, thus enabling the load deep drawing method to determine the drawability of thin metal sheets.View full abstractDownload PDF (1295K) -
Atsumi Ohno1970 Volume 34 Issue 2 Pages 244-248
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS99.99%Al, Al-Ti alloys, and Al-Cu alloys were melted in graphite crucibles. The metals were cooled by placing a cold iron block on the molten surface. As the amount of Ti or Cu increased, an equiaxed chill zone appeared. However, when the same metals were poured into stainless steel cups and cooled from the bottom by water spray, no equiaxed chill zone appeared.
When 0.10%Ti alloy was poured into a stainless steel cup, the macrostructure as a whole consisted of fine equiaxed grains. But, when the cup was placed in cold water, the solidified structure formed a columnar zone in the outer layer of the ingot.
Hence, these results disprove the copious nucleation theory and suggest that the chill zone is formed by precipitation of fine grains which were produced as a result of remelting due to temperature fluctuations at the initial stage of solidification.View full abstractDownload PDF (1315K) -
Zen-ichiro Morita, Yoshikiyo Ogino, Hiroyuki Kaito, Akira Adachi1970 Volume 34 Issue 2 Pages 248-253
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is well known that density as well as viscosity is quite important as a “structure sensitive” property to investigate the structure of liquid metals and alloys. For the purpose of obtaining some information on the density and structure of liquid iron and nickel, the density and buoyancy of these melts were accurately measured in the temperature range from their melting points to 1660°C by means of a modified Archimedean bi-sinkers method. The continuous measurement of buoyancy was very effective to detect any changes in the liquid structure. The results of this measurement showed that the liquid iron had an abrupt change on its structure at the temperatures between 1600° and 1623°C. This structural change may be well explained by the speculation that liquid iron has a delta-like structure (bcc) below about 1600°C, but it breaks down and the randomness of atomic distribution in liquid increases at the temperature corresponding to the structural change. On the other hand, such a structural change was not recognized in the liquid nickel.View full abstractDownload PDF (2106K) -
Kazuhide Tanaka1970 Volume 34 Issue 2 Pages 254-255
Published: 1970
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (398K)
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