著者
永田 和宏
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.84, no.10, pp.715-720, 1998 (Released:2009-06-19)
参考文献数
7
被引用文献数
2

Tatara was used to be a traditional process to produce solid steel, so called "Kera", and/or liquid pig iron, so called "Zuku", from iron sand and charcoal using the box type furnace with blowing cold air intermittently. A modified Tatara furnace has been examined on the production mechanisms of "Kera". Temeratures and oxygen partial pressures in the furnace were measured by means of thermocouples and oxygen sensors with solid electrolyte of zirconia. Iron sand and a piece of "Kera" produced in the bottom of furnace were sampled and analyzed chemically or by a electron probe micro analyser. Iron sand is reduced above tuyere and absorbs carbon on fired charcoals in front of the tuyere at about 1350°C. Many small balls of liquid steel with different carbon content were found in molten slag pool of FeO-saturated silica, so-called "Noro", and cohere each other to grow into a bloom. The characteristics of Tatara steelmaking process are low temperature for carbon absorption of steel at about 1350°C, high oxygen potential in the molten slag of FeO-saturated silica and hypo-eutectic carbon content in steel.
著者
内藤 誠章 武田 幹治 松井 良行
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.100, no.1, pp.2-30, 2014 (Released:2013-12-31)
参考文献数
218
被引用文献数
3 6

The modern blast furnace operation at integrated steel works in Japan has started in 1901 by the first blown-in of Higashida No. 1 blast furnace in Yawata Works, while a 150 years history of Japanese steel industry has dated back to the first western blast furnace built by T. Ohashi in 1857. The steel industry has been supporting the Japanese economy as a key industry which supplies base materials for social infrastructure and developments throughout the pre and post war periods.After the recovery period from the war destruction, Chiba Works of Kawasaki Steel Corp., were built and started its operation in 1953 as the first integrated steel works in Keiyo Industrial Region after the war. During the rapid growth period, many coastal steel works equipped with a large blast furnace more than 3000m3 and some of 5000m3 were built for the efficient marine transportation of raw materials and steel products. Most advanced technologies, high pressure equipment, stave cooler system and bell-less charging system etc., were introduced, improved and has risen to the top level in the world with low reducing agent ratio (RAR), energy saving and long service life of a blast furnace and coke ovens.Energy shift from oil to coal by the oil crisis, cost oriented operation design and technology were tackled and the hot metal of about 80 million tons is manufactured with 27 blast furnaces including over 5000m3 large scale blast furnaces in 2012. During this period, our industry has faced many economical and social pressures of high exchange rate of yen, oligopoly of mining market, global warming problem, and surge of iron ore and coal prices by the rapid growth of the BRICs. We have kept our competitive positions by developing advanced technologies on pulverized coal injection, extended use of low cost iron resources, recycling for environment and CO2 mitigation technologies.Prospects of ironmaking technologies for other decades are discussed by reviewing various papers published and looking back the history of ironmaking developments during the last 100 years.
著者
佐々木 直彦 堀井 胤匡 藤原 幹男 斎藤 英之 三澤 俊平
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.86, no.1, pp.45-50, 2000-01-01 (Released:2009-06-19)
参考文献数
13
被引用文献数
3

Micro-strucure, micro-hardness and micro-absorbed impact energy in the Japanese sword have been investigated to clarify excellent mechanical properties of the Japanese sword. The Japanese sword specimen used in the present research has been made by using TSUKURIKOMI process which combines four kinds of steels; HAGANE (edge), SHINGANE (core), MUNEGANE (back) and KAWAGANE (side) steels, with different carbon contents. By this process, HASAKI (edge) side becomes high carbon steel and MUNE (back) side possesses low carbon steel. The cooling velocity in quenching of the Japanese sword is controlled by TSUCHIOKI treatment which coats the clay thinner in the HASAKI side and thicker in the MUNE side. The HASAKI side is quickly cooled and the MUNE side is slowly cooled. The micro-structure in the HASAKI side shows martensite while the MUNE side shows the coexist structure of ferrite and pearlite. The HASAKI side has a lower value while the MUNE side shows a higher value in the micro absorbed impact energies obtained with the 1.0 and 0.7 mm square miniaturized specimens. It has been shown clearly that the TSUKURIKOMI and the TSUCHIOKI processes give the excellent gradated balance of strength-toughness to the Japanese sword.The ORIKAESHI (folding) forging has an effect both on the carbon content and as quenched hardness in HAGANE steel. The most suitable times of ORIKAESHI cycles which adjust to the carbon content of 0.55-0.60 mass% and hardness of 800HV1 have been determined to be thirteen times. These times of ORIKAESHI cycles correspond to the optimum traditional cycles lying between twelve and fifteen times. The present research from the viewpoint of the metallurgy sheds light on the empirical rule in the traditional Japanese sword processing.
著者
富永 在寛 八塚 健夫 庄野 四朗
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.46, no.1, pp.7-11, 1960 (Released:2012-07-12)
参考文献数
5

To measure the wearing state of a blast-furnace brick-work during its operation, a test method using a radioactive isotope (Co60) was investigated. In this report, some basic investigations which include the measurement of absorption coefficients of the blast furnace construction materials, determination of the burying amounts of Co60, and experiments with a brick-work model are described.
著者
伊藤 孝矩 山﨑 重人 光原 昌寿 中島 英治 西田 稔 米村 光治
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
pp.TETSU-2016-107, (Released:2017-03-06)
参考文献数
37

Creep properties and microstructures for a polycrystalline Ni-based heat-resistant alloy whose grain boundaries were covered by dense intergranular intermetallics were investigated. Creep tests were carries out at 850°C and 80-130 MPa. The creep strength of this alloy was higher than the Alloy617 and HR6W, and equal to the Alloy740, which are pre-existing candidate materials for steam pipes of A-USC power plant. The retardation of acceleration of creep rate was observed characteristically in the creep curves. This retardation behavior was deeply related to the superior creep strength of this alloy. The spherical Ni3Al (γ’) particles were distributed uniformly in the grain interior, whose coarsening behavior was monotonically dependent on the creep time. The intermetallics of Laves phase and σ pahse were formed densely at grain boundary. High coverage ratio of the intergranular intermetallics was maintained until the later stage of acceleration creep region. Therefore, it suggested that the retardation of creep acceleration was not caused by the precipitates behavior of intragranular γ’ particles and intergranular intermetallics, though both the precipitates were understandably effective against the creep strengthening. The plate-like Laves phase was formed in the grain interior during creep. The evolution of volume fraction of intragranular Laves phase depended on not creep time but creep strain. From the results of SEM/EBSD analyses and TEM observations, it revealed that the intragranular Laves phase enhanced the work-hardenability due to the constraint on plasticity and originated the retardation of creep acceleration.
著者
池田 義雅 高村 正人 箱山 智之 大竹 淑恵 熊谷 正芳 鈴木 裕士
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
pp.TETSU-2017-080, (Released:2018-02-05)
参考文献数
17

Neutron engineering diffraction is a powerful technique which provides the information of the micro structure of steels in bulk-average, while X-ray diffraction or Electron backscatter diffraction can provide information only from the surface layer. However, such measurement using neutron diffraction is typically performed in a large facility such as a reactor and a synchrotron, while a compact neutron source has never been used for this purpose. Authors have recently developed a neutron diffractometer installed in Riken Accelerator driven compact Neutron Source (RANS) and succeeded in the measurement of texture evolution of a steel sheet. In this study, we made an attempt to measure the volume fraction of retained austenite by RANS. Background noise was carefully eliminated in order to detect as many diffraction peaks as possible with low flux neutrons. The volume fraction was estimated by Rietveld analysis. The accuracy of the measurement result was discussed by comparing with those obtained by a large neutron facility (J-PARC TAKUMI). The volume fraction obtained by RANS with reasonable measurement time, i.e. 30-300 min, showed only 1-2% discrepancies with those obtained in J-PARC. These comparisons suggest that neutron diffraction by RANS is capable of quantitative analysis of the volume fraction of crystal phases, showing the possibility of practical use of an in-house compact neutron source in the industry.
著者
藤尾 慎一郎
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.91, no.1, pp.11-15, 2005-01-01 (Released:2009-06-19)
参考文献数
12

This paper focuses on the influence what the AMS-carbon 14 age method attains to the history of the iron in the Japanese Islands.The research team in National Museum of Japanese History makes a clear that the Yayoi period began in 10 Cen. cal BC. However, there was a problem in this.It is iron. If the Yayoi period has started in the 10th Cen. BC, it means that the ironware in Japanese Islands had spread early rather than it spreads in China.The research team reexamined the ironware excavated from Magarita site in the Fukuoka Pref. considered to be the oldest ironware in Japan. Consequently, the excavation situation was indefinite and it turned out that we cannot specify the time to belong.Furthermore, 36 ironwares in the initial and early Yayoi were also already found by that time cannot be specified except for two points. Therefore, it turned out that Japanese ironware appeared in the 3rd century of B.C. What does this mean?Although it had been thought that the beginning of agriculture in Japan and the appearance of ironware were simultaneous, it turned out that agriculture has appeared early about in 700 years. Therefore, it became clear that agriculture of Japan started at the Stone Age.
著者
田村 節夫
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.68, no.15, pp.2108-2115, 1982-11-01 (Released:2010-01-19)
参考文献数
53

高炉耐火物の損傷機構と対策,および耐火物侵食診断技術の現状について概説した.耐火物は種々の原因によつて損傷されるが,いずれにおいても,何らかの形で炉内温度変動が関与しており,損傷の直接原囚として,遠因として,あるいは加速要因として作用する.従つて,炉況の安定が耐火物損傷防止の基本であり,また逆に損傷防止が炉況の安定につながることから,耐火物の寿命延長と安定操業は不可分の関係にある.また損傷機構の解明は,耐火物の材質・構造選定の上からも重要であり,このため損傷過程にある耐火物サンプルの解析あるいは試験室的な損傷状況の再現試験が有力な手段となろう.診断技術については,単に侵食量の推定だけでなく,れんが内で生じる現象,たとえば,き裂の発生,れんがの変質,溶銑の侵入,付着物の形成などの検出,推定まで含めた診断技術の開発が必要である.
著者
久保田 俊輔 峯田 元治 安井 純一 中江 秀雄
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.97, no.11, pp.566-571, 2011-11-01 (Released:2011-11-01)
参考文献数
19

The metallurgical macro- and micro-structure, and the residualstress of the Japanese matchlock gun, fabricated at the late Edo period, have been investigated with an optical microscope, an SEM, an EPMA and an X-ray residual stress meter for estimating the fabricating process and their materials. This gun was fabricated by Udonbari (in Japanese) process, which is similar to that of the Russell's method, tubes was created by the joining together opposite edges of a flat iron strip with an iron core bar. The joining line was wavy. Their residual stress was mainly compressive and the values were from 180 to 280 MPa in the longitudinal direction and from 240 to 380 MPa at the transverse direction.The gun was made of low carbon steel with equiaxed ferrite grains; their grain size was mainly 10 μm partly with 100 μm and exceptionally more than 1000 μm grains. Moreover, we find the special banded structure, consisted of fine ferrite grains bands and large ferrite grains bands.The firing part was fabricated by the joining of five parts for getting the L-shape hole. The female screw was made by forging; therefore the shape was tapered screw and the male screw was cut from a low grade steel bar, confirmed by their macro-structure.
著者
佐々木 直彦 桃野 正
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.93, no.12, pp.792-798, 2007-12-01 (Released:2009-02-13)
参考文献数
6
被引用文献数
3 2

The Japanese sword has excellent strength-toughness balance given by two traditional processes. One process is compounding of inner tough iron and outer strong steel. And the other process is cooling-rate control quenching by using thickness of clay-coating before quenching. However, it is a precondition for acquiring high strength-toughness that carbon content of sword parts are regulated in proper quantities. Carbon content of sword parts is very important and controlled under forging process which contains TSUMI-WAKASHI (forge-welding piled steel chips) work and fold-forging.Therefore, changes in carbon content of TAMA-HAGANE steels and carbon steels under traditional forging process were investigated in this study. Changes in carbon content depended on enclosing decarburized or carburized surface in steel as forge-weld interface. Total changes in carbon content were proportional to total layers of included surface in steel. Changes in carbon content per one forge-welded layer. “d (mass%/layer)” was ruled by carbon content of raw materials “C0 (mass%)”. When C0 is over 0.2 mass%, carbon content of forged steel is decreasing and the more C0, the more |d |. C0 is under 0.2 mass%, carbon content is increasing. The mass of forged steels is 4% increasing per one fold-forging cycle, but d is not affected by changes in mass of them.
著者
高橋 学
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.100, no.1, pp.82-93, 2014 (Released:2013-12-31)
参考文献数
74
被引用文献数
8 5

Development in sheet steels has progressed with a strong relation with automotive industry in Japan. To meet with the requirements from automotive industry, various types of sheet steels including high and ultra-high strength steel sheets have been developed. Progresses in three types of steel series will be discussed by checking the historical facts and technologies and their contributions. Introductions of interstitial free (IF) steel and continuous annealing system are the important events in mild steel developments for panels. Extensive work on finding the optimum mixtures of hard and soft phases to improve elongation of steels contributed to improve the crashworthiness of autobodies. Continuous annealing system also played an important role in producing these advanced high strength steels. Precipitation is used in characteristic ways which is to scavenge solute carbon and nitrogen and to prevent coarse cementite particle precipitation. It is also worth to point out that the strong collaborative activities particularly characteristic in Japan between steel manufacturers and auto companies have affected on the progress in advanced sheet steels.
著者
足立 吉隆 田口 茂樹 弘川 奨悟
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.102, no.12, pp.722-729, 2016 (Released:2016-11-30)
参考文献数
9
被引用文献数
2

Deep learning by convolution neural network (CNN) was applied to recognize a microstructure of steels. Three typical CNN-models such as LeNet5, AlexNet, and GoogLeNet were examined their accuracy of recognition. In addition to a model, an effect of learning rate, dropout ratio, and mean image subtraction on recognition accuracy were also investigated. Through this study, the potency of deep learning for microstructural classification is demonstrated.
著者
弘川 奨悟 田口 茂樹 松下 康弘 足立 吉隆
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
pp.TETSU-2017-003, (Released:2017-04-26)
参考文献数
12

Screening important microstructure factors dominantly controlling a stress-strain curve of a dual phase steel was studied by three kinds of sparse modelling approach; Sensitive analysis, data transformation & variable selection, and Bayesian inference. In addition, an effect of data noise on descriptor screening in sparse modelling was also investigated.