All issues
Volume 30, Issue 2
Displaying 1-19 of 19 articles from this issue
- |<
- <
- 1
- >
- >|
-
Masao Honma, Katsunobu Yamaya, Sougorho Morita1966 Volume 30 Issue 2 Pages 103-105
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe behaviour of precipitates in the heat-affected zone during welding of 17-4 PH stainless steel was investigated by the single bead method of TIG arc, and by the analysis of the results on the small specimens rapidly heated and cooled.
The results were obtained.
(1) In the heat-affected zone of 17-4 PH stainless steel solution treated, the maximum hardness was obtained at about 600°C, which was about 100°C higher than that of the ordinary precipitation treatment. At a high precipitation temperature, the maximum hardness was decreased with time.
(2) In the base metals which were subjected to the welding thermal cycle with the peak temperature of 650°C, there were observed some parts which were not hardened by the precipitation treatment. The softening temperatures by welding thermal cycles in the heat-affected zone of the base metals which were subjected to precipitation treatment ranged between 650° and 900°C, and a complete solution treatment was attained at the temperature above 900°C.View full abstractDownload PDF (913K) -
Yoshihiko Doi1966 Volume 30 Issue 2 Pages 106-111
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS(1) In order to produce pure titanium diboride powder, the mixing mole ratio of TiO2/TiC=1.2/0.8 and B4C=1.1 and the reaction temperature of 1800°∼2000°C are suitable. Titanium diboride powder of remaining carbon<0.4% and of 98% up purity could be prepared in the above condition.
(2) The mechanism of the reaction TiC+TiO2+B4C→2TiB2+2CO was investigated.
(This article is not displayable. Please see full text pdf.)
\ oindentThe reactions (1), (2) and (3) were estimated to occur at the respective temperatures. The activation energy of the reaction (3) is about 20 kcal/mole.
(3) TiB2 compacts were hot pressed at 2200°C in H2 and 95% density was gained. From the theory of hot press the yield stress of TiB2 was estimated to be 17 kg/cm2 at 2200°C and 25 kg/cm2 at 2000°C.View full abstractDownload PDF (2370K) -
Masao Kondo, Toru Arai1966 Volume 30 Issue 2 Pages 112-117
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to explore a new high-speed steel which contains a considerable amount of titanium and has an excellent cutting ability, molybdenum-titanium, (0.78∼1.63%Ti and 1.21∼1.54%C), tungsten-titanium high vanadium and standard type high-speed steels were melted by the submerged arc welding method using the SiO2-CaO-MgO flux and the mild steel electrode wire. The specimens prepared from these materials fully annealed with no forging process, were used for heat treatment tests, electron probe micro-analysis and cutting tests. The results were summarized as follows:
(1) The quenched hardness of titanium high-speed steels was slightly lower. But its tempered hardness was the same as that of standard type high-speed steels, as the secondary hardening in titanium high-speed steels was more considerable.
(2) Titanium high-speed steels contain the MC type carbide which consists chiefly of titanium and vanadium. The carbide is very fine and is more spherical and numerous than the MC type carbide in high vanadium high-speed steel.
(3) In the high-speed cutting condition of the hard steel which requires a high temperature-wear resistance, titanium high-speed steels have the cutting ability which is better than standard type and high vanadium high-speed steels. It is perhaps owing to the differences in the chemical and mechanical properties, quantity, granular shape and distribution between vanadium rich and titanium-vanadium rich MC type carbides.View full abstractDownload PDF (2348K) -
Masao Kondo, Toru Arai1966 Volume 30 Issue 2 Pages 118-123
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs already described in the first report on molybdenum and tungsten high-speed steels which contain 0.78∼1.63%Ti and 1.21∼1.54%C, titanium in Ti high-speed steel forms MC type carbide as vanadium does. Accordingly characteristics of Ti-high-speed steel must depend on the carbon content as well as on the titanium content.
In the same manner as mentioned in the first report, 21 kinds of specimens which consist of 0∼3%Ti and 0.58∼2.34%C were prepared. The present study has been made of the heat treatment and the cutting test to determine the relation mentioned above. The results are summarized as follows:
(1) If the carbon content in the steel is too low (less than 2.06%C for 3%Ti), ferrite appears in the matrix and the expected heat treated hardness cannot be obtained.
(2) On the contrary, if the carbon content is too high (more than 2.18%C for 1.5%Ti, and more than 1.71%C for 0.6%Ti), ferrite appears in the matrix and the heat treated hardness becomes low.
(3) In view of the heat treated hardness and the cutting ability, the relation between Ti content and proper carbon content can be indicated by the following equation. C=0.6(%)+0.2V(%)+0.4Ti(%).
(4) The cutting ability by the fly tool was investigated. The results show that the 0.6%Ti and 1.5%Ti steels are better than the 0%Ti steel, and that the 1.5%Ti steel is the best and the 3%Ti steel the worst.View full abstractDownload PDF (2055K) -
Masao Kondo, Masumi Osawa, Toru Arai, Shin-ichiro Kumagai1966 Volume 30 Issue 2 Pages 124-128
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSince the machinability of sulphurized steel is known to be better than ordinary steel, the high sulphur high-speed steel is in demand of machine shops. The steel containing over 0.2% sulphur is damaged when hot forged, so that bisher sulphur in the high-speed steel fixed to be under 0.2%. The grindability of the high carbon-high vanadium-cobalt high-speed steel is low and often used as cast or built-up welded. Therefore, it is desired that investigations be made to increase the sulphur content. In this research, the chemical composition of the specimens used is 6%W, 4%Mo, 4%Cr, 4%V, 5%Co containing up to 0.5% sulphur, prepared by the Union Melt Welder. Sulphide in the specimens forms very small particles up to 5 μ, independent of the sulphur content, and its amount increases with the sulphur content. The volumetric content of sulphide is 2.0% in the 0.5% sulphur high-speed steel.
The hardness of the specimens obtained by quenching and tempering under various conditions has no relation to the sulphur content, being over HRC 66. The durability of the sulphurized high-speed steel increases with the sulphur content under an abrupt cutting of the easy-machinability carbon steel and under a continuous cutting of the hard special Cr-Mo steel.
The grindability of the sulphurized high-speed steel is superior, and the grindability ratio sulphur, can be expressed by
(This article is not displayable. Please see full text pdf.)
\ oindentwhere S=7.3 at 0.023% sulphur, S=12 at 0.36% sulphur, and S=19 at 0.49% sulphur.
The surface roughness (S) of the ground surface is also improved to S=2.0 s at 0.023%S and 0.9 s at 0.49% sulphur. This shows that the smoothness of the ground surface increases with the sulphur content.View full abstractDownload PDF (954K) -
Masao Kondo, Masumi Osawa, Toru Arai, Shin-ichiro Kumagai1966 Volume 30 Issue 2 Pages 129-133
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe manufacturer of modern high-speed steel produce the sulphurized high-speed steel containing 0.08∼0.15% sulphur. If the durability of the steel is not decreased, further additions of sulphur may be effective to increase the grinding radio. The high-speed steel is used not only as forged or rolled but also as cast conditions, and the latter sometimes shows excellent durability.
In this study, the specimens are heat treated as a cast structure, as described in the 1st report. The base composition of the specimen is 5%W, 5%Mo, 4%Cr, 4%V. Various amounts of sulphur up to 1.3% is added to the specimens. Data on the sulphurized high-speed steel (4 kg ingot), hot rolled after the addition of 0.12% sulphur, are also reported.
The results of this study are as follows:
(1) There is no effect of sulphur additions on the hardness of the quenched and tempered specimens.
(2) The specimens containing less than 0.94% sulphur show no difference in the durability of the cutting tests, i.e., interrupted cutting, high speed continuous cutting, and low speed continuous cutting.
(3) Grindability is improved by the addition of sulphur. For example, the grindability for 0.2% sulphur is about 10, but that for 1.0% sulphur is increased to about 22.5.
(4) Machinability of the steel containing 0.12% sulphur, forged and rolled, is improved clearly in the drilling test.
(5) Bending strength is not affected by the addition of sulphur.
(6) Wear of the sulphurized high-speed steel is reduced up 0.2∼0.5% sulphur, and is increased with further sulphur additions.View full abstractDownload PDF (1422K) -
Toshio Doi, Masao Mitani, Tadashi Umezawa1966 Volume 30 Issue 2 Pages 133-138
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNb-Zr-Ti ternary alloys of varying compositions were produced by levitation melting, and the critical temperature, critical current density vs. applied magnetic field, electrical resistivity at 293° and 77°K were measured in addition to observations of the optical microscopic structure.
The critical temperature of the Nb-30 at%Zr alloy showed a maximum value of 10.9°K. Since over the wide composition range the critical temperature was found to be over 8°K, there is the possibility that these alloys can be used as solenoids for the superconducting magnet.
Especially, the critical current density vs. applied magnetic field of the Nb-40 at%-10 at%Ti alloy was favorable, and the critical current density at the applied magnetic field was 4.0×104, 2.7×104 and 1.5×104 A/cm2 at 60, 70 and 80 KOe, respectivery.
In this experiment, the uniform cold working and heat treatment were carried out on the specimens. Therefore, further improvement in the properties of the alloys may be achieved by some other alternative treatment.View full abstractDownload PDF (1613K) -
Toshio Doi, Humihiko Ishida, Tadashi Umezawa1966 Volume 30 Issue 2 Pages 139-145
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAlthough the critical temperature and the critical field of hard superconductors are determined basically by the intrinsic properties of material, the critical current depends on the internal structure of material such as the magnitude of the localized internal stress due to the dislocation, precipitation, composition fluctuation, etc.
Accordingly, a study of superconducting properties of Nb-Zr-Ti ternary alloys requires a phase diagram. In this report, a Nb-Zr-Ti ternary phase diagram at the temperatures of 570°∼1100°C, at which the eutectoid transformation and the two-phase decomposition occurred, was examined by means of microscopical and X-ray analysis. The isothermal sections at 1100°, 900°, 800°, 700 and 570°C are shown Figs. 1, 4, 5, 6 and 7.View full abstractDownload PDF (2912K) -
Yutaka Honda, Sadayoshi Nagata, Shuichiro Takahashi1966 Volume 30 Issue 2 Pages 146-150
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe plasticity of fused UO2 single crystals in the temperature range from room temperature to 500°C has been examined by indenting a diamond pyramid indenter of a micro-hardness tester and by observing slip lines and dislocation etch pits with an opticaland an electron-microscope. The decrement of hardness of UO2 crystals at elevated temperatures was larger than that of Al2O3 and of WC. Before the occurrence of cracks, slip lines appeared around the indentations of UO2 crystals indented at room temperature. The domain of slip lines was widely spread when UO2 crystals were indented at higher temperatures. Dislocation densities, which were determined by counting the number of etch pits near the indentations of UO2 crystals indented at room temperature, 200° and 500°C, were 1.9×107/cm2, 5.4×107/cm2 and 2.1×108/cm2, respectively, while 8.5×106/cm2 in the as-received UO2 crystals.
Plastically deformed domain in the indented UO2 crystals was recrystallized by annealing at 1500°C for 1 hr in hydrogen atmosphere, and the dislocation density decreased to 1.5×107/cm2.View full abstractDownload PDF (2373K) -
Mamoru Nakamura1966 Volume 30 Issue 2 Pages 151-156
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAt present it is generally accepted that steels hot worked prior to quenching is mechanically superior to conventionally quenched steels. In order to make clear the reasons why these thermomechanically treated steel have higher strength, the hardness test, and optical and transmission electron microscopic observations were carried out. In the low carbon steels such as containing 0.1%C it was necessary to work at temperatures higher than 1000°C so as to increase the hardness, whereas in the medium carbon steels (0.47%C) a much lower working temperature was sufficient. From transmission electron microscopic observations of these martensite, the following results were obtained. (1) In case of the 0.1%C steel, the martensite plates were curled and was high in dislocation density, contrary to the straight and clear sharp plates observed in conventional martensite. This fact suggests that the martensite plates show a higher density of lattice defects such as dislocations due to the hot working of austenite and the martensite transformation. (2) When 0.47%C steels were worked and quenched at 900°C, martensite plates were closely similar to those of the lower carbon martensite but the wider width of the former, and a cloudy distribution of dislocations was observed. (3) Internal twin faults were observed in the martensite in every case when worked and quenched in the temperature range of 900°∼1200°C, the density of which seemed to be higher than that conventionally quenched.View full abstractDownload PDF (2337K) -
Hideo Kaneko, Taiji Nishizawa, Akira Chiba1966 Volume 30 Issue 2 Pages 157-163
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPhase diagrams were constructed for Fe-B-Cr, Fe-B-Ni, Fe-B-Cr-C and Fe-B-Cr-Ni-C systems with a view to get fundamental data on boride phases in stainless steels containing boron. The results obtained were as follows:
(1) Fe2B and Cr2B were found to exist in equilibrium with the Fe phase in the Fe-B-Cr system. The solubility limit of Cr in Fe2B was about 10%, and that of Fe in Cr2B was about 60%.
(2) A boride phase found in the Fe-B-Ni system was (Fe,Ni)2B. The Fe2B-Ni2B system was confirmed to be a continuous solid-solution.
(3) Three boro-carbide phases were identified in the Fe-B-Cr-C and Fe-B-Cr-Ni-C systems equilibrated at 700°C. The most predominant boro-carbide was (Cr,Fe)23(C,B)6. The atomic concentration-ratio of B to C in the phase varied from 0 to 2.5, depending on the contents of B, C and Cr in the alloy. With increasing of the equilibration temperature, boro-carbide phases dissolved into austenite leaving boride phases, Fe2B or Cr2B, because B atoms could not dissolve into the austenite matrix.View full abstractDownload PDF (2960K) -
Tetsu Oi, Kikuji Sato1966 Volume 30 Issue 2 Pages 164-168
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMicrostructural changes of the 0.22% carbon-1.12% chromium-0.28% molybdenum steel were investigated by the electron transmission method chiefly during the tempering process. The results are as follows:
(1) The as-quenched material consists chiefly of the needle-like martensite grain about 0.4 μ in width.
(2) The Widmanstätten precipitates are developed most remarkably by tempering at 250°C for 1 hr, and the length of the larger ones ranges from 3000 to 6000 Å.
(3) Each dislocation line in the martensite grain becomes distinguishable after tempering at 500°C for 1 hr.
(4) Decomposition of the martensite grain into the subgrains and spheroidized precipitates takes place after tempering at 600°C for 1 hr.
(5) Clear subgrains are formed after tempering at 700°C for 1 hr.
(6) Selective growth of the precipitates on the subboundaries occurs during tempering at 700°C for 4 to 14 hr.
(7) Images which are thought as dislocations and stacking faults are frequently observed in the spheroidized cementite grains grown after annealing or prolonged high temperature tempering.View full abstractDownload PDF (1430K) -
Yuzi Iwata, Yukiteru Asayama, Akira Sakamoto1966 Volume 30 Issue 2 Pages 169-175
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHydrogen embrittlement of ultra-high strength steels is a problem of great importance in view of the increased use of these steels in airframe application. In order to estimate the influence of carburization or decarburization during austenitizing treatment in an endothermic gas atmosphere of controlled carbon potential on the susceptibility for hydrogen embrittlement of 4340 steel heat-treated to a tensile strength of 190 kg/mm2, tensile tests and stress rupture tests were performed with cadmium plated notched specimens (Kt=3.9). The results obtained are as follows:
(1) The susceptibility for delayed failure or hydrogen embrittlement is increased by carburization and decreased by decarburization. It seems that this behavior is caused by the essential characteristics of martensite that the toughness decreases largely as the carbon content increases, and depends on the carbon content of the surface layer rather than the carburized or decarburized depth.
(2) Notch tensile strength and reduction in area are decreased by carburization and increased slightly by decarburization.
(3) The fracture surface of delayed failure consists of the hydrogen embrittled cracking area and the final fracture area. Hydrogen embrittled crackings of delayed failure appear intergranular with respect to pre-austenite grain boundaries, but crackings during cathodic charging in the absence of applied stress occur most likely around inclusions and show a transgranular mode.View full abstractDownload PDF (2001K) -
Takashi Sakaki1966 Volume 30 Issue 2 Pages 175-179
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBy applying a spectrophotometric method with xylenol orange to the determination of bismuth in barium-ferrite, a rapid determining method has been established.
The xylenol orange complex of bismuth is formed quantitatively in a perchloric acid medium of 0.1∼0.2 N. The absorption maximum of this complex is at 520∼532 milli microns. However, the relation between the bismuth content (0.00∼0.30 mg/50 mL) and the absorbance follows Beer’s law only at the wavelength of 540 milli microns. In this method, there is no significant effect even in case 20 mg each of alminium and iron, 0.1 mg each of antimony, tantalum and tin, 2 mg each of arsenic, molybdenum, titanium and zinc, 10 mg each of barium, cadmium, calcium, cobalt, lead, magnesium, manganese, nickel and strontium, 0.5 mg of chromium, 5 mg each of copper and vanadium, and 1 mg of tungsten are contained in the separated sample solution. Niobium and zirconium interfere.
However, niobium does not interfere, if it is separated as niobium pentaoxide, and the effect of zirconium can be eliminated by the use of sodium fluoride.
The time required for the analysis by this method is about 30 minutes.
The bismuth contents in the actual samples were measured by this method with satisfactory results.View full abstractDownload PDF (1184K) -
Noboru Matsumoto1966 Volume 30 Issue 2 Pages 180-185
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe equilibrium constant for the reaction, C(in liq. Fe)+O(in liq. Fe)=CO(gas), has been studied by many workers, but their results do not agree with each other in the range of high carbon contents. In this range, the oxygen content is so small that accurate measurements of its values are difficult. The oxygen content is, however, to be proportional to the CO-pressure in the equilibrium state. For this reason, the experiments under high pressure were undertaken.
A pressure tight furnace was constructed. At the temperatures of 1200°∼1500°C, the oxygen content which was equilibrated with 0∼25 atm CO in carbon-saturated molten iron was measured by the vacuum fusion method. In the case of the furnace cooled samples, the analytical values of oxygen ranged from 20 to 40 ppm and were independent of the CO-pressure. It was considered that these samples absorbed a large quantity of oxygen after the sampling. In the case of the cast samples in the copper mould, on the other hand, the analytical values ranged from 2 to 10 ppm and the dependence on the CO-pressure was represented by A×PCO+B at each temperature where A was 0.23 and 0.16 (ppm/atm) at 1200° and 1500°C, respectively. It was concluded that the terms A×PCO and B correspond to the dissolved and absorbed oxygen, respectively.
At the temperatures of 1200° and 1500°C, the equilibrium constant K′(=PCO⁄%C×%O=1⁄A×%C) is 10,000 and 12,000, and the activity coefficients of oxygen f0 are calculated to be about 2 and 3 in the carbon-saturated melt. The values of interaction parameters, e0(c)=∂logf0⁄∂%C and ε0(c)=∂lnγ0⁄∂Nc, are calculated to be about 0.1 and 5 at these experimental temperature. It should be noticed that these results are different in sign from the experimental results by other workers.View full abstractDownload PDF (1454K) -
Zenichiro Takao, Satoshi Miyoshi, Ichiro Kamigaito, Takehiko Kawaguchi1966 Volume 30 Issue 2 Pages 186-190
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the production and quality control of zirconium and its alloys, it is the most important problem to determine trace hafnium rapidly and accurately because of its high absorption cross section for thermal neutrons.
This paper describes the method for the determination of hafnium in reactor-grade zirconium and also in commercial grade zirconium.
The metal was converted into the oxide by chemical treatment. Sample electrodes were prepared by coating with a thin layer of oxide powder on the flat top of a 5 mmφ graphite rod. The analysis was performed with the 3.4-meter Ebert mounted grating spectrograph using Raiskii spark excitation.
Analysis of several unknown samples containing 100 ppm Hf, determined independently by other physical methods, showed good agreement. The precision was 3% for 0.20 to 5.00% Hf and 8% for 40 to 600 ppm Hf.View full abstractDownload PDF (1014K) -
Tetsuo Matsumura, Yasuo Kudo, Takehiko Kawaguchi1966 Volume 30 Issue 2 Pages 191-195
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA spectrographic method for determination of trace hafnium in zirconium and its alloy was developed and the discharge of a high voltage condensed spark was employed for exciting the solid sample. The primary object of this investigation, was to find the optimum, condition of excitation to detect trace hafnium less than 100 ppm. By using Raiskii spark excitation, the required sensitivity and reproducibility were obtained.
With some modifications in the excitation condition and with the addition of a low speed emulsion, the method was also applied to the determination of hafnium in the percent range.
The analysis was carried out on the line pairs-Hf 2641.4 Å/Zr2653.6 Å in the parts per million range and Hf 2641.4 Å/Zr 2761.9 Å in the percent range. The precision of the method was ±2 to ±12% at the level of 100 ppm and ±5% at the level of 2 to 3%.
The method offers an increase in speed and improved stability as compared with most of the previous methods for the determination of hafnium by means of excitation of the oxides.View full abstractDownload PDF (1392K) -
Tadatoshi Toda1966 Volume 30 Issue 2 Pages 195-200
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe Cu-Ag alloys containing about 4%Ag shows solid solution strengthening and age-hardening effects, and is used as a high strength and high electrical conductivity alloy. The effects of lead on the hot working properties of the Cu-3.8%Ag alloy were investigated. The experiments performed were drop hammer tests, impact tests, detections of the lead phase by means of an electron probe X-ray micro-analyser (E.P.M.A.), and observations of the alloy structure at a high temperature. Ingots 50 mm in diameter and 295 mm in height, weighing 5.1 kg, were cast from melts of the Cu-3.8%Ag alloy containing 0.005 to 0.5% lead.
The results obtained were as follows: (1) By the method of drop hammer tests and impact tests, the allowable limit of the lead content in the Cu-3.8%Ag alloy was determined. The minimum lead content which caused hot embrittlement in the as-cast alloy was 0.03% and that for the solution treated alloy was 0.08%. (2) It was observed in the experiments by E.P.M.A. that when the specimen contained more than 0.035% lead, the lead phase appeared in the matrix as the secondary phase. The distribution of the lead phase in the matrix was at random both in the grains and at the boundaries. (3) The following mechanism was proposed for the embrittlement of the Cu-Ag alloy by the lead content. Below the melting temperature of the lead phase, the difference of the elastic and plastic properties between the lead phase and the matrix causes a stress concentration at the lead phase under external stress, and leads to embrittlement. At the temperatures above the melting point of the lead phase, the liquid lead “wets” the grain boundaries and decreases the binding strength of the grain boundaries, thus causing the grain boundary embrittlement in the Cu-Ag alloy.View full abstractDownload PDF (1507K) -
1966 Volume 30 Issue 2 Pages 200
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:2.7, ρ(Ω·cm−1), qetween, wich, γ-Al2O3 Right:12.7, ρ(Ω·cm), between, which, Al2O3View full abstractDownload PDF (20K)
- |<
- <
- 1
- >
- >|