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 41

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
21

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
被引用文献数
1

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.
著者
山木 正義
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.45, no.5, pp.528-542, 1959-05-01 (Released:2009-05-26)
参考文献数
91
被引用文献数
1
著者
酒井 久裕 落合 鍾一 上野 學
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.75, no.4, pp.657-664, 1989-04-01 (Released:2009-06-19)
参考文献数
22
被引用文献数
2

The purpose of this work is to present results on the mechanical properties of SUJ 2 bearing steel improved by a cyclic heat treatment. The structure of thermally cycled steel consists of fine-grained ferrite particles of the size under about 2 μm containing fine cementite particles of the size about 0.2μm. Thermally cycled steel was found to be superplastic at 710°C, just below A1 temperature, at an initial strain rate of 1.67 × 10 -4s -1, i.e. elongation to failure was about 500% and the strain rate sensitivity, m value, was about 0.4. The activation energy of about 180 kJ/mol, which is nearly equal to that of grain boundary diffusion of Fe atoms in α-iron, was obtained for this plastic deformation. Furthermore the rolling contact fatigue life test was performed at room temperature under constant load. The fatigue life of SUJ 2 steel thermally cycled was found to be prolonged (about 2.5 times) as compared with that of conventional one.
著者
古谷 仁志 田川 哲哉 石川 孝司
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.5, pp.678-687, 2014 (Released:2014-04-30)
参考文献数
23
被引用文献数
2

Tensile behaviors of cryogenic steels, which contain 0 to 12wt% nickel, were examined to obtain the fundamental knowledge related to the role of retained austenite in the improvement of fracture toughness. Although retained austenite of 8% and 12% nickel steel, which were manufactured by the special heat treatment composed of quenching, intermediate heat treatment, and tempering, was stable under the deep cooling at –196 ºC, it transformed to martensite by straining around 10% at –196 ºC. The strain hardening behavior was divided into two categories. One is that the maximum strain hardening appears just after yielding, then the strain hardening gradually decreases with increasing strain. It was related to 0% to 2% nickel steels, which include less retained austenite. Another is that the strain hardening increases just after yielding with the increase of strain, then it gradually decreases. In this case, higher strain hardening was derived. It was related to 5% to 12% nickel steels which included a certain amount of retained austenite. The increase of strain hardening under low temperature was attributed to the solute nickel and the formation of martensite, which act as a hard second phase, by the work induced martensitic transformation.
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
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.86, no.1, pp.45-50, 2000-01

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 0.7mm 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 0.55-0.60mass% 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
大角 洸平 大塚 敏之 平田 光男 塩谷 政典
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.99, no.4, pp.275-282, 2013 (Released:2013-03-26)
参考文献数
16
被引用文献数
1

In this paper, a control problem of temperature dispersion in steel cooling is formulated as model predictive control (MPC) of a probability density function (PDF). The input of MPC is optimized for dynamics of the PDF approximated by the Monte Carlo method, which is called particle MPC (PMPC). Simulation results of PMPC are presented to show the potential effectiveness of dispersion control.
著者
小野寺 秀博 阿部 太一 下野 昌人 小山 敏幸
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.10, pp.1207-1219, 2014 (Released:2014-09-30)
参考文献数
116
被引用文献数
2 3

Computational materials science is an exciting field which holds much future potential. In this article, at first, the dramatic advances of the computational methodologies are briefly summarized at scales from the atomistic to macroscopic levels. Then, each coauthor introduces the three research fields in detail, (1) CALPHAD modeling supported by key experiments and first-principles calculation, (2) Studies on the phase transformation in alloys based on the MD simulations, and (3) Predictions of the microstructure evolution and the mechanical properties based on the phase-field method, where remarkable progresses have been attained.
著者
小藪 重行
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.29, no.1, pp.54-67, 1943-01-25

The principal causes of erosion in the gun-barrel bore are cracks and the deterioration caused by the action of the gun-powder gas, as well as abrasion due to projectiles passing through. The author investigated microspically and by X-rays the cracks and the characteristic-layer on the eroded surface of the bore. It was ascertained that the characteristic layer has a structure which has become martensitic due to the heating effect of the gun-powder gas. At the instant of discharge, the barrel, expands and contracts, and also the hard layer itse'f does so due to the heating effect of the gun-powder gas, so that innumerable number of cracks occurs on that layer by repetition of such actions. The gun-powder gas penetrates through these cracks and accelerates the erosion. Thus it was concluded that the action of the gun-powder gas is the fatal cause of the deformation of the bore by erosion.
著者
浜田 幸一 井坂 和実 土居 大治 米満 善久 岩崎 信吾
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.2, pp.66-72, 2002-02

Clad steel sheet is formed by cladding different metals and used for the functional material, which has convenient characteristics of each metal. Especially, a lot of stainless steel/aluminum clad strip is produced for electromagnetic rice cookers which are in demand because of the higher thermal conductivity, having magnetism and corrosion resistance. For the demand, continuous cladding technology of the wide width stainless steel/aluminum strip has been developed by warm rolling after the rapid heating process. Recently, much higher uniformity for peeling strength is required as the market grows. So, a new heating process, in which uniform heat generation is achieved by the electric resistance of metals and the directly applied current, is developed in place of the conventional process of induction heating. After solving some technical problems about sparks and temperature uniformity, direct resistance heating equipment have installed in the manufacturing line. As the result, high-quality clad steel sheets, which have the uniform peeling strength, can be produced by the improvement of temperature deflection on rolling.
著者
辻畑 敬治 宮川 奨蔵 大坪 茂 大野 重治 花木 功
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.46, no.4, pp.455-460, 1960-04-01

In line with the starting of experiments on the use of self-fluxing sinter in blast furnaces, the experimental production of lime sinter using 5∿10% of lime stone was conducted at Kukioka D. L. Sintering Plant since May, 1958, and from the operation data the following items were inferred : - 1) Although in lime sinter the mean grain size was getting smaller, the amount of the fine fraction (minus five millimeter fraction) became rather decreased than in normal sinter, from which it was inferred that lime sinter was more improved in point of grain distribution. 2) Lime sinter had almost the same degree of strength as normal sinter. 3) By adding 5∿10% of lime stone, the output of sinter was increased by 4∿6.5%. When calculated in terms of iron, the output, however, was almost constant. 4) In case of using the burden of 100% lime sinter, operation was carried out with special attention paid to the control of basicity, and for that purpose such measures as the use of foreign fine ores divided into the three classes according to SiO_2 content, etc. were enforced, and, as the result, the sinter that could almost satisfy the requirements of blast furnaces was able to be produced. 5) Cost of sinter production was decreased by 2% and 5.5% by the addition of 5% and 10% of lime stone, respectively, but the cost in terms of iron was almost unchanged. For these reasons it was concluded that lime sinter was superior to normal sinter.
著者
篠竹 昭彦 松崎 眞六 国友 和也 内藤 誠章 橋本 操 圃中 朝夫 長根 利弘 永嶺 謙忠 田中 宏幸
出版者
The Iron and Steel Institute of Japan
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.95, no.10, pp.665-671, 2009
被引用文献数
1 7

The visualization of the inner state of a blast furnace was investigated by exploiting the feature of cosmic-ray muon that attenuates according to the density and the thickness of the object through which it penetrates. The distribution of the cosmic-ray muon accumulated in an object in a blast furnace during a certain period has been determined by a probing system provided with two sets of a pair of panels with plastic scintillation counters segmented in parallel along each direction of both sides. First, measurement was performed in the furnace hearth structure that had been taken out after the shutdown of Oita No. 2 Blast Furnace repaired in 2004. Next, another measurement was performed in the same manner in the renewed furnace hearth of Oita No. 2 Blast Furnace which had just started working after its repairs. The density of the material at the iron-rich portion inside the hearth was estimated from the accumulation ratio obtained from the relation between the intensity of the muon channel passing through the iron-rich part in the hearth and that passing through its opposite channel symmetric to the coordinate origin. Then, the level of the furnace bottom brick, meaning its eroded thickness, was estimated from those accumulation ratios in relation to each channel crossing both the iron-rich part and the furnace bottom brick. The possibility of the density distribution of the material inside a blast furnace and the remaining thickness of bricks being estimated by this measurement method was identified.
著者
永田 和宏 古主 泰子 松原 章浩 國分(齋藤) 陽子 中村 俊夫
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.105, no.4, pp.488-491, 2019 (Released:2019-03-31)
参考文献数
16
被引用文献数
1 1

The Japanese nails had been produced by the traditional ironmaking way of Tatara until the Edo period since the late of 6 Century. The Tatara is characterized as the ironmaking using very fine iron sand as the resources and is distinguished from the pre-modern ironmaking way in Europe using lump iron ore. The quality of the Japanese nails is affected from steel produced by Tatara in each age. The 14C ages of 3 Japanese nails were measured with accelerator mass spectrometry and calibrated to calendar years. Each 14C age provided plural calendar year periods with definite probabilities, and one of the periods determined in comparison with the history of temples and their repair records. The production ages of nails used in the Daibutuden of the Todaiji temple, the living quarters of the Manshuin temple and the Zaoudo of the Yoshino-Kinpusenji temple are before 1692, the 12 Century and before 1592, respectively, when they were repaired or reconstructed.
著者
天藤 雅之 竹下 哲郎 中澤 崇徳 木村 英隆 安保 秀雄
出版者
The Iron and Steel Institute of Japan
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.79, no.1, pp.98-104, 1993-01-01 (Released:2009-06-30)
参考文献数
14
被引用文献数
14 21

Room temperature creep behavior has been investigated for typical stainless steels (SUS304, SUS430, SUS410L). The mechanism of creep is discussed in comparison with creep data on a carbon steel (SM400).The results are summerized as follows:1) Stainless steels showed creep deformation at a stress around 0.2% proof stress. Though creep rate decreased monotonously with increase in time, deformation did not ceased even at a time 1000 h. The creep curve of SUS304 steel followed a logarithmic creep law.2) No creep was observed in steel SM400 below a critical strain rate at around 10-8S-1.3) The facts that interstitial free steels showed room temperature creep, and that SUS304 steel showed no creep at 300°C suggest that the suppression of creep can be attributed to the dynamic strain aging due to the interaction between dislocation and interstitial carbon and nitrogen atoms.