著者

大中 都四郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.35, no.3, pp.69-73, 1949-03-25

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Detailed physico-chemical studies have recently been made on many important phenomena occurring in the steelmaking furnace. It is, however, desirable to consider all the operations used in the process as a whole, in order to see whether these operations are really necessary and sufficient in their mutual correlations. Standing upon the standpoint mentioned above, the author analysed physico-chemically these mutual correlations of the entire procedure in the open hearth process. As examples, data obtained from a practical acid open hearth process were used. As the result of it, it becomes clear that the open hearth process now successfully applied is generally reasonable to remake massively steel scrap by means of melting process. The result of these analyses will be successively reported. In this first report, the objects of the remelting proccess of steelscrap are discussed. That is : - (1) The steel bath has to contain finally standard amount of Si, Mn, C uniformly mixed (2) has to have neccessary temperature, (3) its O content has to be kept in such amount as to be able to be removed with deoxydizing agents (4) it has to be not gasious (5) the slag contacting with it has to have less oxydising ability.

著者

東 司 田中 泰彦 石黒 徹

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.76, no.5, pp.783-790, 1990-05-01

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Grain refining behavior during austenitizing of 3.5%Ni-Cr-Mo-V turbine rotor shaft steel was investigated. Special attention was paid on the effect of Ni content and role of fine carbide precipitates on the austenite transformation and migration of the acicular austenite grain boundary. The microscopic observation of grain refining behavior reveals the following results. (1) The grain refining of 3.5%Ni-Cr-Mo-V steels during austenitizing occurs through two stages. The first stage is austenite transformation which γ-phases succeed to the acicular bainitic ferrite structure. The second stage is the formation of equiaxed grain at higher temperatures by the migration of grain boundary of the acicular austenite. (2) Driving force of the grain boundary migration in the second stage is considered to be the high density defects in the acicular austenite. (3) Increase of Ni content stabilize the acicular γ-phases up to higher temperatures. This decreases the formation of equiaxed grain due to the migration of acicular austenite grain boundary. (4) Increase of V content makes the grain refining difficult because the fine carbide precipitate such as VC works as a barrier against the grain boundary migration required for the formation of equiaxed grain.

著者

村田 純教 鷹見 恭平 神谷 美紗紀 森永 正彦 橋詰 良吉 三木 一宏 東 司 石黒 徹

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.88, no.4, pp.214-221, 2002-04

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In recent advanced high Cr ferritic steels, it is known that the Laves phase precipitates during creep test when the steels contain a relatively high level of Mo+W content. The Laves phase is believed to be granular in shape and to exist in the boundaries of lath, block, packet and prior austenite grains, but a number of fine Laves-phase precipitates are found to exist even inside the martensite lath in the tempered steels containing 10 mass% Cr and 4.6 mass% W. The shape of this Laves phase is plate-like, and the size is below 300 nm. The crystallographic relationship between the fine Laves phase and the matrix phase is as follows; (111)_<ferrite>//(001)_<Laves> and [01^^-1]_<ferrite>//[110]_<Laves>. In the microstruc ture aged at 923 K for 7〜14 Ms, the fine precipitates of the Laves phase disappear inside the martensite lath, and coagulated Laves phase is observed at the lath-, block-, or packet- boundaries. Only the low C steel containing 0.08% C and 3% W shows a few amounts of the fine precipitates of the Laves phase after aging at 923 K for 7.268 Ms. This compositional dependence of the precipitation behaviour can be understood qualitatively with the aid ofthe System-Free-Energy Concept.

著者

角屋 好邦 馬越 龍太郎 河合 久孝 守中 康治 三上 真人 添田 暉平

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.87, no.8, pp.564-569, 2001-08

被引用文献数

1

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The 2.25CrMoV steel is applied to conventional combined high-pressure (HP) and low-pressure (LP) rotor forging, and it has excellent creep properties and toughness at 538℃ conventional steam temperature. However, at 566℃ steam temperature, it is required to improved the properties of the rotor forgings. The effects of chemistry on toughness and creep rupture strength have been investigated on the 9CrMoV base materials for the purpose of developing a new HP-LP rotor material for 566℃ steam temperature. Thus 9.8Cr1.4Mo1.0NiVNbN steel, named HLP9F, with higher toughness and creep rupture strength compared with conventional 2.25CrMoV steel, has been developed. A trail HP-LP rotor forging with the diameter of LP section of 1800mm and that of HP section of 1200mm has successfully been manufactured through the VCD process from 68t ingot. In spite of a large ingot, neither chemical composition change nor eutectic Nb(C, N) formation could be recognized. The rotor, furthermore, exhibited satisfactory quality in toughness and creep rupture strength. This rotor material is suitable to the HP-LP rotor material for advanced combined cycle steam turbine.

著者

吉岡 洋明 伊藤 裕道 田中 泰彦 池田 保 美

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.89, no.6, pp.705-710, 2003-06

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To meet the requirements for optimum utilization of power station sites and economic realization of coal fired thermal units, tandem compound 60 Hz 1000 MW large thermal units were developed. One of the most critical items was development of a large-size high strength generator rotor forging with comparable toughness to the conventional rotor forging. Based on the investigation results of existing rotor forging, chemistry optimization was conducted within the specification of conventional turbine generator and low pressure rotor forging by using lab oratory heat materials and 0.28%C-0.25%Mn-4%Ni-1.75%Cr-0.4%Mo-0.12%V high purity steel was selected for the candidate material. Double tempering heat treatment of 550℃ and 580℃ was also developed for increasing the yielding ratio of 0.02% yielding stress to tensile strength to meet the requirements of mechanical properties. According to those laboratory studies, one trial rotor forging with the same diameter as production ones was successfully produced.

著者

郡司 好喜

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.80, no.4, pp.N176-N186, 1994-04-01

被引用文献数

1

著者

竹越 晋一 小山 力也 平松 大三 永尾 卓己

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.71, no.13, 1985-09-05

著者

佐々川 清

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.21, no.6, pp.473-480, 1935-06-25

著者

田部 三郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.57, no.3, pp.629-645, 1971-03-01

著者

松下 幸雄 後藤 和弘 長 昭二 五十部 賢次郎 楯 昌久 笹生 宏明

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.52, no.3, pp.393-396, 1966-03-01

著者

飛鷹 秀幸 木村 勇次 高木 節雄

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.85, no.1, pp.52-58, 1999-01-01

被引用文献数

6

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Mechanical milling using high energy planetary ball mill was applied to Fe-C alloy powders with (ferrite+cementite) two-phase structures to give an ultimate large strain into the powders. Dissolution behavior of cementite during mechanical milling was investigated in relation to ultra grain refining of ferrite matrix, and dissolution capacity of cementite was discussed in terms of carbon content in the powders. Ultra grain refining of ferrite matrix to about 10nm results in full dissolution of cementite in the powders with carbon up to 2 mass% C. Most of carbon, which has been rejected from decomposed cementite, is suggested to segregate at grain boundary to form amorphous layer. Thus, it was proposed that the dissolution limit of cementite depends on both volume fraction of the grain boundary amorphous layer and carbon concentration therein. For example, as the maximum carbon content of the grain boundary amorphous layer was to be about 4.2 mass% C, the dissolution limit of cementite was estimated at 30 vol% from the mass valance for carbon content in the case ferrite grains were refined to around 10nm. This volume fraction of cementite is just correspondent to that in Fe-2mass%C alloy.

著者

永澤 清

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.19, no.3, pp.174-196, 1933-03-25

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In this investigation, a statistic survey on the phenomenon of temper-brittleness is made with 164 actual charges of plain carbon and special steels. The results show that the temper-brittleness is primarily related to the constitution of steel. The elements Cr, Mn, Si, Ni and P are confirmed to promote the phenomenon. Closer observation of the phenomena reveals the fact that there are two kinds of temper-brittleness : - the one is observed at the tempering range 450°&acd;525°, and is not affected by the rate of cooling after tempering, while the other occurs above 525° and shows the vast difference in the impact value between rapidly cooled and slowly cooled samples ; which has hitherto been known as the temper-brittleness. To distinguish these two kinds of temper-brittleness the present authur has called the former as the "First Temper-Brittleness" and the latter as the "Second Temper-Brittleness" respectively. The so-called carbide theory has been developed. When martensite, a super-saturated solid solution f carbide, is tempered, the precipitation of the carbide occurs at the tempering range 450°&acd;525°. This precipitation is the cause of the first temper-brittleness ; at the tempering temperature above 525° the redissolution of the precipitated carbide bigins to take place as the result of the increaing solubility of the carbide in α-iron. This causes the difference of impact value between rapid and slow coeled samples, that is the second temper-brittleness. The carbide, which causes the temper-bittleness, is ascertained to be Fe_3C or its solid solid solution ; and it is considered that the occurence of the temper-brittleness in steels depends on the correlation of these carbides and α phase. It is possible, in all steels, to observe more or less the first temper-brittleness, which is considered to be the combined effect of Si, Mn, P and eventually Cr present in the steels. It has often been reported that even in the case of samples having an identical composition and subjected to the same heat treatment, there is a great variation in the susceptibility of the temper-brittleness. The present authur believes that this is due to the existing oxides in the steels, and the more the oxides present, the larger the ratio of the susceptibility. The remeding action of Mo and W is confirmed in the temper-brittleness of several steels, and its mechanismis is described.

著者

小林 佐三郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.22, no.9, pp.688-702, 1936-09-25

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(A) Silicate inclusion. 1) The author investigated on the silicate inclusion of steel from melt to ingot by Dickenson method. 2) Silicate are diminished when the slag composition is higher acidic and the oxygen contents of molten steel is small. 3) Also, silicates are decreased by the use of Si-Mn and Fe-Ti as deoxidiser. 4) Addition of Fe-Mn during the boiling period is effective for diminition of silicate. 5) Generally, silicates of ingot show maximum value at inside of the bottom and outside of the top. 6) Large Mn-silicate remains in ingot when the addition of Mn is too much (B) Flakes. 1) Existence of flakes can be detected by deep etching with alcoholic solution of HNO_3. 2) Segregations, cracks and low-silica-silicates of ingot give much effect on the formation of flakes. 3) Forged steels in which flakes appear, have partially martensitic structure caused by segregation of alloying elements. 4) Slow cooling after forging is most effective for prevention of flakes.

著者

田中 義人 達脇 正雄 阿澄 一寛 高間館 千春 堀田 一之 岡田 道雄 新谷 進

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.68, no.12, 1982-08-20

著者

向井 楠宏 増田 竜彦 吉富 丈記 原田 力 藤本 章一郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.70, no.8, pp.823-830, 1984-06-01

被引用文献数

10

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Laboratory corrosion test of clay-bonded SiC specimen at the slag surface has been carried out in argon, argon-oxygen and air, in order to elucidate the mechanism of local attack of blast-furnace-trough material at the slag surface. The local corrosion arises only in the oxidizing atmosphere in the narrow zone just above the slag surface. The corrosion zone of solidified specimen during the progress of the corrosion is covered with thin liquid slag film. Supplying rate of oxygen from the atmosphere gives remarkable influences on the relations between the corrosion rate and dipping times, slag compositions, etc. It is estimated that the slag film, crept up from the bulk slag, plays important roles in the occurence of the local corrosion by accelerating mass transfer and causing the abrasion of the specimen due to its active movements in diffusion layer caused by Marangoni effect. SiC granules on the surface of the specimen are oxidized by iron oxide in the film into carbon granules, which causes Marangoni effect and also facilitates the dissolution and abrasion of the specimen. Some countermeasures against the local corrosion have been offered from the corrosion mechanism.

著者

横川 孝男 石黒 隆義 半沢 貢 征矢 勇夫 横田 彦二郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.64, no.4, 1978-03-03

被引用文献数

1

著者

青木 裕幸 武田 欣明 中嶋 睦生 迫村 良一 笹川 正智 半澤 和文

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.71, no.12, 1985-09-05

被引用文献数

1

著者

西澤 泰二

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.75, no.12, pp.2137-2138, 1989-12-01

著者

山岸 静直 半明 正之 小倉 英彦 田巻 直 外村 勝生 船越 邦治

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.68, no.11, 1982-08-20

著者

柳本 左門 玉野 敏隆

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.56, no.8, pp.1118-1135, 1970-07-01