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Volume 26, Issue 9
Displaying 1-15 of 15 articles from this issue
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Shoichi Katoh1962 Volume 26 Issue 9 Pages 553-557
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the previous reports, it was reported that the creep rupture properties of modified iron-base heat-resisting alloys hardened by precipitation were comparable to those of Nimonic 80A and M-252. In the present investigation, the structural stability of various alloys containing Ti 2% and Al 2% at high temperatures was examined. The matrix of specimens was varied from Ni-rich to Fe-rich compositions. 16 mmφ forged bars were used for age-hardening, electron-microscopic and X-ray diffraction tests. By X-ray diffraction tests on the electrolytic extracts from these specimens after 1000 hr aging, MC, M7C3, M23C6, γ′, σ and β phases were identified. High Ni alloys had remarkable age-hardenable characteristic by the precipitation of γ′ phase. On the other hand,low-Ni high-Fe alloys had no remarkable age-hardenable characteristics and showed over-aging phenomenon after long time aging treatment. The deterioration of age-hardenable characteristics in these low Ni high Fe alloys have relation to the precipitation of massive β phases. The structure of β phase is a body-centered cubic,CsCl,B2 type. Iron and cobalt can be partially substituted for nickel, and aluminum for titanium, so that,the general composition is probably (Ni,Fe)(Al,Ti) or (Ni,Fe,Co)(Al,Ti). By studying pseudo ternary series Fe-Ni-Cr-Co at 732° and 815°C, the matrix composition regions in which β phase precipitated was determined. The various intermetallic compounds in quarternary series NiAl-NiTi-FeTi-FeAl and NiAl-NiTi-CoTi-CoAl were synthesized by vacuum-arc melting technique, and it was demonstrated that these synthetic β phases are crystallographically analogous to precipitated β phases. The behavior of precipitated β phase was investigated by determining the pseudo quarternary diagrams of Ni-Fe-Al-Ti and Ni-Co-Al-Ti systems.View full abstractDownload PDF (688K) -
Shogo Kanazawa1962 Volume 26 Issue 9 Pages 557-561
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is well known that when steel is hot-quenched to the temperature range of lower bainite formation and is partially transformed isothermally the residual austenite is stabilized and austenite (γR) retained at room temperature is increased. In the previous reports(1)(2)(3), however, the author indicated the existence of the effect of stress on the formation of martensite nuclei in addition to the hitherto known effect of stress on the driving force of martensite transformation, and assumed the coherent embryos of martensite formed due to Bain’s strain to explain the opposite effect of tension and compression upon the transformation. In the precent study, the author investigated how austenite is stabilized when steel is held isothermally in the temperature range of unstable austenite under the load of tension or compression. The experimental results obtained were as follows: (1) When samples of steel were held in incubation time, there was no change in the amount of γR irrespective of the holding temperature and the application of stress of positive or negative sign. Therefore this substantiated the results obtained in the previous report that “the amount of γR was dependent upon the temperature range in which the stress was applied.” (2) In the bainite temperature range the incubation time was shortened as a result of shear stress effect irrespective of its sign. At room temperature, however, tensile stress increased γR and compressive stress decreased γR (as in the case of stress effect during continuous cooling disclosed in the previous report), owing to the opposite effect of stresses, depending on whether the sign is positive or negative, and on the number of nuclei formed after holding the samples for a certain time. Thus it was confirmed here again that there was an effect of stress on the number of martensite nuclei.View full abstractDownload PDF (682K) -
Shogo Kanazawa1962 Volume 26 Issue 9 Pages 562-566
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt seems to be a useful information in heat treatment technique, particularly in hardening, to understand the effect of various tensile stresses applied during cooling upon the Ar′ transformation, as well as the effect of stress upon the martensite transformation, as already reported in the previous papers(1)∼(4). Therefore, I have conducted various experiments were conducted and the following results were obtained: (1) When tensile stress was applied in cooling process, the upper critical cooling velocity in hardening increased approximately in proportion to the square of stress and its increasing rate was larger as the temperature at applying the stress was higher. For instance, if the tensile stress of 13.8 kg/mm2 was applied at 850°C in high carbon chromium steel, its critical cooling velocity became seven times as large as the value in the case of no load. (2) The tensile stress applied isothermally moved the beginning and ending curves of isothermal transformation diagram to the left side in accordance with the value of stress. This occured both in pearlite and bainite ranges. (3) As for the effect of stress upon the continuous cooling transformation, it was also found that the stress moved the beginning curve of transformation diagram to the left and upper side. (4) It was proved that the quenched hardness was considerably influenced by the tensile stress as a result of the promotion of Ar′ transformation as mentioned above. (5) The experiments were conducted only on the case of tensile stress in this study. According to the results obtained previously(4), however,it may be reasonable to infer that compressive stress may exercise almost the same effects.View full abstractDownload PDF (1226K) -
Shigeo Horiuchi1962 Volume 26 Issue 9 Pages 566-570
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has been reported that the wear-resisting property of cast iron is improved by sulphurizing treatment. In the present study, the surface of cast iron (3.10%C, 1.62%Si) sulphurized in H2S at 500°C for 2 hr was polished with emery paper 04# and its surface layer was studied by reflection electron diffraction, electron microscope and micro-vickers test. The results obtained were as follows; (1) Beneath the outermost scale which was easily peeled mechanically, there was a sulphurized layer of dark grey. (2) The maximum hardness was attained, when the thickness of the specimen was decreased by 0.1 mm by wearing, and the flowing of α-Fe as well as the slipping of graphite was observable by electron diffraction and electron microscope. (3) The promoted slipping of graphite might be one of the reasons why sulphurized cast iron shows a good wear-resisting property.View full abstractDownload PDF (576K) -
Hisasuke Takeuchi, Tadatoshi Toda1962 Volume 26 Issue 9 Pages 570-575
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe copper side phase diagram of the Cu-Co2Si alloys was determined and their precipitation hardening properties were studied. Specimens were prepared from vacuum melted alloys, using the mother alloy Co2Si and electrolytic copper. The results obtained were as follows: (1) The liquidus and the solidus in the phase diagram were determined by thermal analyses, and it was found that the alloys containing less than 5%Co2Si solidify as solid solution. The solid solubility of Co2Si in copper determined by metallography was as follows: 2.3% at 1050°C, 1.2% at 1000°C, and 1.0% at 850°C. (2) The optimum processes of heat-treatment to obtain the highest mechanical strength of the Cu-Co2Si alloys were solution treating for 1 hr at 1000°∼1050°C, and aging for 1 hr at 500°∼550°C. The Cu-Co2Si 4% alloy treated in this way showed the following properties. Tensile strength: 76.5 kg/mm2, elongation: 6%, Vickers hardness: 240, electrical conductivity: 48.5 I.A.C.S.%. (3) The configuration of added elements in the Cu-Co2Si 4% alloy was investigated by X-ray diffraction analyses. Co2Si phase was detected in both the as-cast and the as-aged specimens.View full abstractDownload PDF (1280K) -
Hisasuke Takeuchi, Tadatoshi Toda1962 Volume 26 Issue 9 Pages 576-579
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrical resistivity at high temperature, the effects of cooling rate on the formation of supersaturated solid solution, and the Vickers hardness at high temperature for the Cu-Co2Si alloys were investigated. The results obtained were as follows. (1) A self-recording apparatus was used to measure the electrical resistivity of the Cu-Co2Si alloys between room temperature and 600°C. No discontinuous change was found, but smooth changes representing continuous precipitation were observed. (2) In order to find out the critical cooling rate in the solution treatment for the Cu-Co2Si 4% alloy, C curves were determined by isothermal treatment and aging. The nose of C curve was located at about 950°C. The supersaturated solid solution of this alloy was obtained at room temperature, when the cooling rate between 1000°C and 800°C was higher than 20°C/sec. (3) Vickers hardness measurement at high temperature were made on various copper alloys i.e. tough pitch copper, Cu-Cd, Cu-Ag, Cu-Cr, and Cu-Co2Si alloy. The Cu-Co2Si 2.8% and 3.6% alloys showed the highest hardness value of about 95°C among those copper alloys at 500°C, and this value is nearly equal to that of room temperature hardness of quarter-hardened tough pitch copper.View full abstractDownload PDF (610K) -
Takeaki Sato, Yoshinobu Sawada, Saburo Shimodaira1962 Volume 26 Issue 9 Pages 580-584
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to decrease the damage of water turbines or water pumps caused by sand erosion, three different types of sand erosion tyests were carried out; (a) Erosion caused by collision with sand. (b) Erossion caused by friction of running sand. (c) Erosion caused by friction due to the rotation of metals in sand. In the case (a), the results show that the erosion loss is nearly proportional to the cube of relative velocity and also proportional to the size of sand. In the range of relatively small amount of sand, a linear relation between the amount of sand and the erosion loss was observed. Erosion loss is nearly in inverse proportion to the hardness of metal. It has been also found that copper alloys are less strong than ferrous alloys in the case of same hardness. In the case (b), the erosion loss is nearly proportional to the relative velocity. The relation between the hardness of metals and the erosion loss is similar to the case of (a). A complicated relation between the loss and the hardness was observed in the case (c). In this case, the metal particles produced during the experiment should serve as erosive materials. The results indicate that the erosion loss increases with increasing hardness in the range of lower hardness, but decreases with increasing hardness, in the range of higher hardness.View full abstractDownload PDF (714K) -
Minoru Okada, Shigeo Shin, Masakazu Miyagi, Hiromi Matsuda1962 Volume 26 Issue 9 Pages 585-590
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe joining mechanism of ultrasonic welding has not yet been explained. We have studied this mechanism by means of microscopic observation, X-ray diffraction, temperature measurement of joined parts, X-ray microanalysis etc. The results obtained were summarized as follows. (1) The sections of joined parts seemed to show that these parts are heated over the recrystallization temperature, according to the microscopic observation. None of intermetallic compounds and other phases were observed by electron microscopy. (2) The recrystallization patterns of X-ray diffraction were observed in the junctions between two different metal foils. Neither phases such as intermetallic compound nor other crystal structure were observed. (3) The temperature of joined parts was measured with an alumel-chromel thermo-couple and on oscillograph, and the temperature rise was found to be most affected by changing ultrasonic power. (4) X-ray microanalysis showed that the interatomic diffusion occurred at the ultrasonic bond between copper and titanium. (5) The joint strength of the bond was much influenced by the aging condition for the age-hardenable alloy; the joint strength of Cu-Be alloys treated at 350°C for 15∼30 min was about twice of that of unaged ones.View full abstractDownload PDF (1072K) -
Susumu Yoshida, Yukio Ohba, Norio Nagata1962 Volume 26 Issue 9 Pages 590-595
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs a method of studying the mechanism of fracture, the electron-microscopic examination of fracture surfaces by means of replicas has proved to be very useful. This work has been undertaken to examine by this method the submicroscopic structure of tensile fracture surfaces of pure chromium as recrystallized or prestrained under several conditions. The results obtained are as follows: (1) Specimens as recrystallized: The fracture surface consists of flat cleavages and cleavage steps. The cleavage steps are rather small in their density and some of them are presumed to be due to secondary cleavage. (2) Specimens slightly prestrained: The density of cleavage steps increases and they form “river patterns”. (3) Properly prestrained and ductile specimens: The three following kind of fracture surfaces are found in mixture. Type-A: Comparatively flat smooth surface. Type-B: Surface covered by shallow dimples. Type-C: Rough surface consisting of numerous, submicroscopic unit cleavage facets. (4) Overprestrained specimens: The fracture surface is composed of cleavage surfaces entirely covered by well-developed river patterns. (5) Specimens properly prestrained and annealed: The fracture surface is composed of ductile regions which are similar to Type-A surface in (3) and brittle ones which are just like the brittle cleavages in (4). Based upon the above observations, discussion have been made about the mechanism of ductile and brittle fracture in pure chromium.View full abstractDownload PDF (2590K) -
Hiroshi Sakao, Kokichi Sano1962 Volume 26 Issue 9 Pages 596-600
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe equilibrium of the reaction between oxygen in liquid Fe-Ni-Cr alloys and H2-H2O gas mixtures has been measured at 1600°C. Combining the present experimental data with the previous ones on the similar equilibrium in the systems of Fe-Ni, Fe-Cr and Ni-Cr alloys, the relationship between the apparent equilibrium constant and the ternary alloying composition was determined. From these, the isoactivity coefficient curves for oxygen were drawn in the ternary alloy field. Furthermore, the deviation of the Wagner’s relation from the present results on the activity coefficient of oxygen was examined. In order to keep the deviation below ±10%, the alloying compositions must be limited as follows;
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (790K) -
Yoshiro Yagi, Tôru Yukawa, Shunji Yamamoto, Masaaki Teragaki1962 Volume 26 Issue 9 Pages 601-606
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHeat-treatments and the mechanical properties of Ti-6Al-4V alloy, a representative α+β type titanium alloy, were investigated. A homogenous ingot of the alloy was prepared by consumable-electrode double-arc melting. Quenching tests from various temperatures have revealed that α-β transus occurs between 1000° and 1050°C and the quenched structure from β phase is α′, and that the minimum hardness was obtained when the alloy was quenched from the temperature range of 700°∼800°C and the hardness rapidly rose when it is quenched from temperature levels above 900°C. Aging tests of specimens solution-treated at 850°, 950° and 1100°C were carried out at various temperatures from 200° to 600°C for various periods from 30 min to 4 hr. The hardness rose to the maximum at the aging temperature within the range of 400°∼500°C and rose with rise of the temperature of solution-treatment. The tensile strength, the elongation and the reduction in area of the annealed specimens (700°C×2 hrs, furnace-cooled) were 100 kg/mm2, 16% and 44%, respectively, in room-temperature tests. In the high-temperature tests up to 700°C,only the tensile strength was reduced but the other values increased. The Charpy impact value in room-temperature test was 5 kgm/cm2, but increased under higher temperature. The tensile strength of specimens aged at 450°∼550°C for 24 hrs after solution treating at 850°∼950°C rose with the rise of the solution-treating temperature and the drop of aging temperature. Creep and creep-rupture tests of heat-treated specimens, solution-treated at 850° and 950°C and aged at 550°C for 24 hrs, were carried out at 427°C(800°F) under the stress of 25.6 kg/mm2 and 63.3 kg/mm2, respectively. The creep-resistance and the creep-rupture time increased with the rise of temperature of solution-treatment. The lowest creep strength was obtained with annealed specimens.View full abstractDownload PDF (1159K) -
Reiichi Ohno1962 Volume 26 Issue 9 Pages 607-612
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of sulfur on graphite and eutectic cell formations in the solidification of cast iron have been investigated. Experiments have been carried out by the addition of sulfur alloys to synthetic Fe-C,Fe-C-Si,Fe-C-P and Fe-C-Si-Mn alloys under argon atmosphere at 1350°C in a molybdenum furnace. When sulfur was added as Fe-C-S and Fe-C-Si-S alloys, in each of hyper-eutectic Fe-C and Fe-C-Si alloy systems, there is a range over which the obstruction of graphitization does not further proceed by the increase of sulfur. The appearance of such a range is considered to be due to the existence of effects of sulfur which promote graphitization in solidification. In a series of experiments where an Fe-C-S alloy was added to an Fe-C-P alloy, sulfur maximizes graphite flake size in a certain concentration and on the number of eutectic cells it has an effect showing the minimum in a certain sulfur concentration. An explanation for these effects was attempted on the base of growth and nucleation theories of crystals. In a series of experiments where an Fe-C-Si-S alloy was added to an Fe-C-Si alloy and Fe-C-Si-Mn alloys containing 0.1 to 0.5%Mn, the effect of sulfur on graphite flake size was decreased by the presence of manganease, which shows the formation of MnS in solidification.View full abstractDownload PDF (914K) -
Zen-ichi Tanabe, Saburo Shimodaira1962 Volume 26 Issue 9 Pages 612-616
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs a reason for the widespread use of aluminium bronze in industrial engineering may be cited its high mechanical and excellent corrosion resisting properties. In certain corrosive environments, however, aluminium bronze can suffer a selective corrosion known as dealuminization. Dealuminization in aluminium bronzes is similar in mechanism to the dezincification that occurs in brasses. It is generally known that all phases in aluminium bronze except α phase are susceptible to dealuminization. The effect of isothermal transformation on dealuminization of a eutectoid aluminium bronzes was studied by means of rapid dipping corrosion tests and anodic polarization measurements with a potentiostat in several kinds of solutions. The results obtained were as follows: (1) Dealuminization increased with advance of isothermal transformation, and remarkable increase of dealuminization was observed in alloy in which precipitation of pearlite was detectable. (2) Effect of the isothermal transformation on dealuminization was most evident in acidic aqueous solution.View full abstractDownload PDF (985K) -
Tatsuo Maekawa, Sadayoshi Nagata, Masaru Kagawa, Nobuwo Nakajima1962 Volume 26 Issue 9 Pages 616-621
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of cold-working on corrosion of AISI type 304(or 304L) stainless steels were investigated in high-purity water at 300°C under pressure of 87 kg/cm2. An X-ray diffractometer used to investigate the ferrite formation caused by cold-working. The corrosion results were compared with the corrosion in boiling 65% nitric acid and in boiling copper sulfate-sulfuric acid solution. The results are summarized as follows: (1) The degree of cold working does not seem to have a direct relation to the corrosion resistance of type 304 (or 304L) stainless steel in high temperature water and in boiling 65% nitric acid. (2) The ferrite produced by cold-working accelerates the corrosion in high temperature water. However, the ferrite does not seem to affect the corrosion resistance in boiling 65% nitric acid and in boiling copper sulfate-sulfuric acid solution. (3) The tensile strength measurement indicate the existence of the intergranular attack in high carbon specimens after the test in boiling copper sulfate-sulfuric acid solution. However, no evidence of intergranular attack is found in high temperature water.View full abstractDownload PDF (1067K) -
1962 Volume 26 Issue 9 Pages 622
Published: 1962
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see PDF Wrong:(1250°C×1.5′), [in Japanese], [in Japanese], [in Japanese], Photo. 2 Right:(1250°C×15′), [in Japanese], [in Japanese], [in Japanese], [Please see PDF]View full abstractDownload PDF (58K)
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