鐵と鋼
Online ISSN : 1883-2954
Print ISSN : 0021-1575
38 巻, 5 号
選択された号の論文の16件中1~16を表示しています
  • 石塚 寛
    1952 年 38 巻 5 号 p. 278-282
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    The variations of non-metallic inclusion was measured by microscopic method during the refining process of 50ton acid open-hearth furnace (lime process) in the case of chromium alloy steel, and the relation between the inclusions and the refining conditions was investigated. In this report are indicated the refining conditions to make refined steels.
    The most profitable refining conditions for reduction of non-metallic inclusion were as follows:
    (1) Fit silicon amount at melt-down is about 0.4 per cent.
    (2) Chromium amount at melt-down must be as little as possible.
    (3) Fit decarburizing amount at the oring period is about 0.6-0.7 per cent and at the liming period is about 0.5 percent.
    (4) Fit use of ore is about 25-30kg per ton and lime-stone is about 7-10kg per ton.
    (5) Average decarburizing velocity must be within about 0.0024-0.0028 C% per min.
    (6) The oxygen amount in molten steel must be decreased as fast as possible after deoxidation.
    (7) At the time of pigging, ferro-silicon and ferro-manganese are to be added simultaneously with the preliminary deoxidizer.
    (8) Before ferro-chromium addition, large quantity of ferro-silicon must not be added.
    (9) Fit silicon amount before tapping-off is about 0.33-0.40 per cent.
    (10) The necessary ratio of Si/Mn ranges 1/1.5 to 1/2 to reduce the non-metallic inclusion.
  • 森 一美, 松下 幸雄
    1952 年 38 巻 5 号 p. 283-288
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    In order to study the properties of molten slags, it is one of the most important problems to measure their electrical conductivity, which shows most probably that they consist of several ions,
    This paper deals with the electrical conductivity of the systems Na2O-SiO2, CaO-SiO2 and MnO-SiO2 in molten state.
    The specific conductivities (κ) of these systems are of the order of 0.1-1 Ω-1 cm-1, and increase with temperature. The conductivity of the system MnO-SiO2 suddenly decreases in the neighbourhood of the solidifying temperature. At constant temperature the conductivity rises with inrrease of basic oxides. Further logκ is linear, being plotted against 1/T (T: absolute temperature).
    Additionally we attempted the electrolysis in the system CaO-SiO2. The concentration of CaO is larger at positions near the cathode than near the anode. The result indicates that Ca++ migrates to the cathode.
    The conduction mechanism is ionic, and refering to the specific conductivity of fused salts, it has heen established that molten slags are highly dissociated into ions.
    The mechanism of viscosity and electrical conductivity are described on the basis of the model of quasi-crystal. The linear relationship between logκ and 1/T can be shown theoretically. The activation energy of viscosity is greater than of electrical conductivity. This fact indicates that viscosity is mainly controlled by the large silicate ions, while perhaps the conduction by the cations.
    The fact that electrical conductivity rises with increase of basic oxides is partly due to the increase of the numher of cations. Further it is also controlled by the mobility of ions.
    In the system CaO-SiO2 the rate of the increase of the conductivity with CaO % decreases at high CaO contents. This may be due to the fact that the strong bonds are formed between Ca++ and SiO44-.
  • 中川 義隆, 曾我 政雄
    1952 年 38 巻 5 号 p. 289-296
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    The authors obtained the following relationships by statistical investigation in the data of ingot making practice:-
    (1) Reciprocal relation of various ingot casting conditions.
    (2) Characteristics of various kinds of steel in the ingot casting.
    (3) Characteristics of various kinds of furnace steel in the ingot casting.
    (4) Empirical formula of reciprocal relation between casting temperature, casting velocity and tundish nozzle diameter worked out by statistical calculation.
    (5) Relation between various ingot casting conditions and ingot skin.
    (6) Relation between various defects rising on ingot (sand crack, goast and forging crack etc.) and conditions of ingot casting practice.
    And so the best and reasonable conditions for good ingot making were obtained.
  • 下村 力
    1952 年 38 巻 5 号 p. 296-301
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    The improvement on the cupola malleable iron was discussed by the duplex melting practice using 2t-cupola and 4t reverberatory furnace.
    The molten metal in the cupola was transferred with its slag into the reverberatory furnace, the slag was skimmed off, and the melt was adjusted in its composition and deoxidized. In this practice the relation between the chemical composition of the slag formed in the cupola and the mechanical properties of the annealed products was examined.
    When all the melting conditions except the blast-one were constant and the subsequent annealing cycle is also constant, the mechanical properties of the product were considerably influenced by the ratio CaO/SiO2 of the cupola slag even if the chemical composition of the melt appeared constant.
    When the ratio CaO/SiO2 in the cupola slag was increased, the graphitization cycle could be shortened and the mechanical properties of annealed products are improved. To improve the properties of the products, the oxidation of molten iron in cupola must be avoided as much as possible and the superheating of melt in the forehearth (in this case reverberatory furnace) was absolutely needed.
  • 井上 勝郎, 副島 恒夫
    1952 年 38 巻 5 号 p. 301-305
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    In the manufacture of seamless steel tubes by the use of the Stiefel-Mannesmann piercing mill, we are often annoyed by cracks on the outer surfaces of tube blanks. These cracks are mainly due to seams on the surface of round billets, but the standard of judging their harmful nature has not been yet made clear. The authors collected many examples of them, and studied the microstructures and depth variations along their axis after classifying them into 6 groups, and then heated these specimens in the heating-furnace, checking the changes of their crosssectional form and depth. On the other hand, the authors pierced about 70 examples of round billets and compared the cracks of tube blanks with the duepth of seams. Making use of these results obtained, the authors concluded as follows:
    (1) Cracks appeared on the outer surface of hollowed pieces are due to seams on the surface of round billets. If the seams are removed before piercing, no crack appears. The kinds and appearance of seams have no bearing upon the cracks of hollowed pieces and the dominant factor is the depth of the seams.
    (2) The boundary depth on which the harmfulness of the seams of billets may be decided as follows:
    a. 0.7mm under is harmless.
    b. From 0.7mm to 1.4mm is harmful or harmless according to circumstances, inasmuch as the scale-off amount of billets varies from place to place between these amounts.
    c. 0.7mm up is always harmful.
    The above conclusions were confirmed by actual experiments.
  • 岡本 正三, 鳥取 友治郎
    1952 年 38 巻 5 号 p. 306-312
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    The relation between the microstructure and the modulus of elasticity of cast iron has been studied. The modulus was measured by the flexure method, a mirror being used and the loading being increased step by step at the middle point of specimens held at two points. The results are as follows:
    (1) The modulus of elasticity is changed mainly by the form and quantity of graphite contained in iron, and the value increases considerably as the form varies from flake to spheroid in grey iron, the concentrations of the common elements in it being held alinost the same in each iron.
    (2) The increase in quantity of graphite having the similar form reduces the modulus of elasticity, and the rate of the decrease is smaller in nodular iron than in flaky iron.
    (3) The changes of the modulus due to the nodule numbers of graphite, the structures of the matrix and the increase in the concentration of Si, are markedly smaller than those due to the form and quantity of the graphite.
    (4) With the temperature rise, the modulus decreases at first slowly and then rapidly at about 300°C. The decreasing rate is large in flaky iron compared with those in malleable iron and nodular iron.
  • 特殊鑄鋼の燒入,燒戻性
    三ヶ島 秀雄
    1952 年 38 巻 5 号 p. 313-321
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    The author studied on the relationship with the quench-hardening and grain size of some special cast steels which were made to add Ni, Mn, Cr, Al, Al alloys and Ca-Si in Cr-Mo cast steels. It was found that the larger the grain size was the more remarkable the quench-hardening effect become. Futher the quench-hardening effect was affected by the irreversibility of steels such as element Ni, Mn, Cr, which made decreased the transformation point of steel. It was presumed that the low carbon steel rapidly increased in quench-hardening with the addition of Ni. If the C content was large, however, the hardenability was not so marked as that of the low C steels. On the other hand, the addition of Mn and Cr had a pronounced effect than Ni.
    The author also investigated the relationship of such alloy steels with nonmetallic inclusions and quench-hardening. Though the quench-hardening increased with increase of Ni, Mn or Cr content, the number of inclusions was rather small and the size of it became larger. The number of inclusions increased with the addition of Fe-Si or Ca-Si, while the size of it became finer.
    The impact resistance decreased considerably with elevation of tempering temperature, and reached a minimum value at 300°-400°C (that is a first temper brittleness), while it markedly increased as tempering temperature were more elevated. In the present report the author also investigated the effect of various elements on the temper-brittleness of Cr-Mo or Cr-Mn-Si cast steels.
  • 山中 直道, 佐藤 恭次郎
    1952 年 38 巻 5 号 p. 321-327
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    It is well known that various kinds of heat-brittleness (carbide brittleness, blue shortness, secondary brittleness, transformation brittleness, red shortness and Heissbruch) are present in steel. the authors found another new heat-brittleness which occures in the wide temperature range from 550°C to 1200°C. When steel bath was deoxidized by inadequate amount of Al and more than critical amount of Al2O3 was retained in steel, austenite grain size at 925°C became very small consequently. In this case a new heat-brittleness was liable to occur.
  • Timken 16-25-6の高温時効に及ぼす成分,温度,時間並びに冷却殘留歪の影響
    淺野 榮一郎
    1952 年 38 巻 5 号 p. 328-333
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
    The age-hardening phenomena of Timken 16-25-6, the heat-resisting alloy for gas turbine material, was studied by determination of hardness and microstructure. There were three different per centage components in the specimens. The contents of carbon were of two kinds, 0.20% and 0.06%. The content of molybdemium were of three kinds, 6%, 3%, and none. Ni, Cr Si and Fe (balance) were kept unchanged.
    The materials were melted by high-frequency furnace and then hot forged to bar. The solutiontreatment were done at 1150°C, for 1 hour. Then the materials were aged at high temperature, (700, 800, and 900°C) from 15 minutes to 50 hours. 6% Mo specimens, which were either of 0.2%C or 0.06%C, had two peaks of hardness, and the latter was harder after 50 hour aging, especially at 800°C.
    It seemed that first peak of hardness mainly depended on some carbon condition, and the second peak of hardness mainly depended on some molybdemium condition. 3% Mo specimens were not as hard even after 50 hours aging, as compared with the 6% Mo specimens. When the specimens were aged, precipitation in microstructure was observed simultaneously. The specimens containing no Mo were not aged ever at high temperature, either in hardness or microstructure.
  • 堀田 秀次
    1952 年 38 巻 5 号 p. 333-336
    発行日: 1952/05/25
    公開日: 2010/01/22
    ジャーナル フリー
    Following th 12 the report, the influence of the heat-treatments on the torsional impact value of the 18-4-1 standard high speed steel were investigated.
    Moreover, experiments were carried out concerning the influence of the principal elemeents of C, Cr, W, V on the torsional impact value, hardness numbers and duration time in cutting test of the 18-4-1 standard type.
  • 生駒 實
    1952 年 38 巻 5 号 p. 337-342
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
  • 小島 義正, 下川 義雄
    1952 年 38 巻 5 号 p. 342-350
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
  • 1952 年 38 巻 5 号 p. 350
    発行日: 1952年
    公開日: 2009/07/09
    ジャーナル フリー
  • 1952 年 38 巻 5 号 p. 351-356
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
  • 1952 年 38 巻 5 号 p. 357-358
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
  • 1952 年 38 巻 5 号 p. 360
    発行日: 1952/05/25
    公開日: 2009/07/09
    ジャーナル フリー
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