著者
滝沢 佳郎 畑 俊彦 遠藤 芳秀
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.70, no.16, pp.2301-2304, 1984-12-01 (Released:2009-06-30)
参考文献数
8

Determination of free nitrogen in steel by constant temperature-hydrogen hot extraction method was studied and optimum analytical conditions were established.1) Lower measured values were obtained with samples that had passed for long time after powdering. 2) The result of 1) was considered to come from the fact that dissolved nitrogen in steel was locked to dislocations and/or formed cluster gradually, thus becoming difficult to be extracted. 3) Higher temperature of environment around samples accelerated these effects, so it must be avoided to heat powdered samples for washing and drying. 4) It is necessary to analyse samples of finer powders soon after powdering. 5) When the sample was analysed under these analytical conditions, free nitrogen could be fully extracted at 400°C.
著者
鷲見 郁宏 佐々 健介 浅井 滋生
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.78, no.3, pp.447-454, 1992-03-01 (Released:2009-05-29)
参考文献数
11
被引用文献数
3

Being aimed to improve the surface quality of a continuously cast steel, a new electromagnetic casting method is proposed where the high frequency magnetic field is imposed on the initial stage of solidification from the outside of a mold. The magnetic pressure induced by the magnetic field provides the solidification taking place under the soft contacting pressure of molten metal with the mold, so called soft contacting solidification. Molten tin was cast by imposing magnetic field with 1.75, 3.75 and 15.4 kHz frequency in order to examine the applicability of the method to the cast of steel. It is found that this electromagnetic casting method has a potential to be applied to the cast of steel. The stronger intensity of magnetic field could provide the better surface quality of products in the way of reducing oscillation marks. However, the excess intensity of magnetic field caused the disturbance on meniscus inducing surface defects. The critical intensity of magnetic field at which the surface defects due to fluid disturbances at meniscus appeared increased with increasing the frequency of magnetic field. It is noticed that the effect of magnetic field on reduction of surface defects appears more significantly when mold oscillation was not applied than when the oscillation was applied.
著者
平島 拓弥 荒牧 正俊 山本 正之 安田 恭野 宗藤 伸治 古君 修
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.101, no.5, pp.308-314, 2015 (Released:2015-04-30)
参考文献数
12
被引用文献数
7 6

Effect of specimen thickness on ductile fracture energy for ferrite-austenite duplex stainless steel was investigated by using tensile strain test. It was revealed that both uniform and local deformation energies decreased with the decrease in the specimen thickness. Voids in a thicker specimen can be easily formed at the lower plastic equivalent strain because of the steep increase in the triaxiality. The decrease in the local deformation energy was due to the void growth near the fracture surface depending on the steep increase in the stress triaxiality.
著者
Ho Yu Il Seop Choi Kyung-Lyong Han Jae Yeon Choi Goobong Chung Jinho Suh
出版者
一般社団法人 日本鉄鋼協会
雑誌
ISIJ International (ISSN:09151559)
巻号頁・発行日
vol.55, no.12, pp.2609-2617, 2015-12-15 (Released:2015-12-25)
参考文献数
11
被引用文献数
25

Handling heavy-load materials is the most common operation in iron and steel making processes. There are numerous operations in which workers directly deal with heavy loads without equipment. The refractory constructions in the converter and AOD (Argon Oxygen Decarburization) furnaces are representative examples. Transferring thousands of heavy materials repeatedly over a long period of time can not only cause musculoskeletal diseases, which occur 70% on the waist and 30% on other parts such as wrists, elbows, shoulders, etc. but also contain latent risks of safety accidents.In this paper, a novel stand-alone powered exoskeleton robot suit was developed for assisting the strength of waist, lower back, and hip joints that are physically vulnerable during handling heavy-load materials. The simple robot structure reduces the frame weight as well enabling easy motion control. The robot is capable of moving freely due to the stand-alone actuators. The developed novel clutch system generates a smooth transition against various working conditions. This technology significantly diminishes the physical fatigue of operators and will subsequently prevent further muscular skeletal disorders as well as safety accidents.
著者
Shigeru Suzuki Koji Hotta Eui Pyo Kwon Shun Fujieda Kozo Shinoda Masayoshi Kumagai Kentaro Kajiwara Masugu Sato Shigeo Sato
出版者
一般社団法人 日本鉄鋼協会
雑誌
ISIJ International (ISSN:09151559)
巻号頁・発行日
vol.55, no.10, pp.2158-2165, 2015-10-15 (Released:2015-10-28)
参考文献数
48
被引用文献数
7

Electron backscatter diffraction was used to observe the microstructure of an austenitic high-manganese twinning-induced plasticity steel and investigate the crystal orientation of grains in this steel. The results showed that mechanical twins are formed in a grain with a high Schmid factor during the tensile test. The orientation data obtained were used to estimate the anisotropic elasticity of the grains in the steel. The microscopic stress and strain evolved in the microstructure of the steel unloaded after plastic deformation were estimated using finite element method simulation in which the elastic anisotropy of the steel was taken into account. The simulation indicated that the evolution of microscopic stress and strain in the microstructure is considerably influenced by the crystal orientation of the grains. Furthermore, white X-ray diffraction with microbeam synchrotron radiation was used to characterize the evolution of microscopic stress and strain in the grains of the steel. The stress analysis during white X-ray diffraction indicated the formation of residual microscopic stress after tensile deformation, which was found to be distributed heterogeneously in the steel. It was also shown that the direction of the maximum principal stresses at different points in the microstructure under loading were mostly oriented along the tensile direction. These results are fairly consistent with the results obtained by the simulation, although absolute values of the real principal stresses may be influenced by the heterogeneously evolved strain and the several assumptions used in the simulation.
著者
Nerea Isasti Pedro Manuel García-Riesco Denis Jorge-Badiola Mitra Taheri Beatriz López Pello Uranga
出版者
一般社団法人 日本鉄鋼協会
雑誌
ISIJ International (ISSN:09151559)
巻号頁・発行日
vol.55, no.9, pp.1963-1972, 2015-09-15 (Released:2015-09-29)
参考文献数
23
被引用文献数
6

In this paper a multi-linear regression analysis is developed to predict continuous cooling (CCT) diagrams in low carbon Nb and Nb–Mo microalloyed steels. The inputs to the analysis include the weight percentage of alloying elements, the prior austenite grain size, the retained strain and the cooling rate. To develop the model, 11 steels with different combinations of Nb and Mo were considered. In some cases, the resulting equations have been validated with external data from the literature. Additionally, the model was also employed to predict hardness and ferrite grain size with the aim of providing a tool to link microstructural features with mechanical property predictions. Both Nb and Mo additions promote a reduction of ferrite and bainite start temperatures, where the effect is more pronounced for Nb in the bainitic region. Both microalloying elements contribute to an increase in hardness and a refinement of the microstructure.
著者
Masayoshi Kumagai Shigeo Sato Shigeru Suzuki Muneyuki Imafuku Hitoshi Tashiro Shin-ichi Ohya
出版者
一般社団法人 日本鉄鋼協会
雑誌
ISIJ International (ISSN:09151559)
巻号頁・発行日
vol.55, no.7, pp.1489-1495, 2015-07-15 (Released:2015-07-30)
参考文献数
19
被引用文献数
1 3

Measurement of the residual stresses in cold-drawn pearlitic steel wire was conducted using an energy dispersive X-ray diffraction technique. The residual stresses of the ferrite and cementite phases were determined for different crystal orientations and large residual stresses were found to exist in the cold-drawn pearlitic steel wire. The residual stresses in the ferrite phase were compressive in the axial direction but nearly zero in the hoop and radial directions. In addition, the residual stresses of the reflection indices for the ferrite phase were similar to one another. For the cementite phase, while tensile residual stress existed in the axial direction, compressive residual stress existed in the hoop and radial directions. These stresses in the ferrite phase in the axial direction and cementite phase in all directions decreased along the radial positions. A residual stress state model was proposed on the basis of the aligned lamellar structure along the drawing direction; the model explains the effect of the lamellar direction on residual stress. Reanalysis of the wire sample using the proposed model provided residual strains and stresses in the lamellar direction that were different from the average values estimated using the simple stress analysis method.
著者
万谷 志郎 的場 幸雄
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.49, no.4, pp.666-672, 1963-04-01 (Released:2010-10-12)
参考文献数
9
被引用文献数
8 7

Equilibrium of phosphorus-carbon-oxygen in liquid iron in contact with a mixture of solid calcium phosphate and calcium oxide was studied in a controlled gas atomosphere of CO-CO2 gas mixture in the range of 0.03-1.2% of phosphorus in liquid iron at 1530.., 1560.., and 1585... It was found that the stable phase of calcium phosphate was of tetracalcium phosphate, 4CaO.P205, at the presence of free lime in this experiments.The results obtained were summerized as follows: (1)(1b)(1c)(2)(2b)(2c)(3)(3b)(3c)
著者
玉木 輝幸 村上 健一 潮田 浩作
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.101, no.3, pp.211-220, 2015 (Released:2015-02-28)
参考文献数
13
被引用文献数
1

A local curvature multi-vertex model was developed. This model is a straightforward two-dimensional topological network model based on physical principles that consider the local curvatures of grain boundaries and the grain boundary tensions at triple junctions. Virtual vertices are set on the grain boundaries in order to calculate the driving forces of grain boundary and triple junction migration. Therefore, the accuracy of the developed model is higher than that of the conventional curvature model and the vertex model. In the proposed model, the generation and annihilation of virtual vertices maintained a proper configuration of virtual vertices, and high accuracy is expected with a suitable set of simulation parameters. The proposed model was verified by the grain growth simulation using adequately determined parameters for the artificially generated specimens with 5040 grains.
著者
松田 昭一 岡村 義弘
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.60, no.2, pp.226-238, 1974-02-01 (Released:2010-10-12)
参考文献数
22
被引用文献数
14 25

The process of formation of austenite has been studied in low-carbon low alloy steels. The specimens with acicular structures such as martensite, bainite or tempered martensite are heated at temperatures between Ac1 and Ac3. The structual changes in these specimens during heating are observed in detail.The main results are as follows.1) Austenitizing processes are divided into two stages. In the first stage globular austenites are formed accompanying the dissolution of cementite. Acicular austenites are as well formed at an early stage.2) In the second stage a globular austenite is formed by the coalescence of the acicular austenite grains and those formed in the both stages grow to form extended austenite grains.3)γ′ transformation prevails in a boron containing steel.Based on these results, it is proposed that the reverse transformation are mainly controlled by the rate of recrystallization of austenite.
著者
Shijing Wang Tatsumi Ishihara
出版者
一般社団法人 日本鉄鋼協会
雑誌
ISIJ International (ISSN:09151559)
巻号頁・発行日
vol.55, no.2, pp.381-386, 2015-02-15 (Released:2015-02-20)
参考文献数
20
被引用文献数
1 4

Solid oxide electrolysis cell for electrolysis of CO2 to CO was studied with the cell using LaGaO3-based electrolyte at the intermediate temperature (i.e. 973–1173 K). Various metal additives to Ni were examined for cathode to CO2 reduction and it was fund that Ni added with Fe shows high activity and the current density of 1.5 A/cm2 was achieved at 1.6 V and 1073 K on Ni–Fe (9:1) cathode. Improved electrolysis activity was explained by the expanded reaction site which may be assigned the fine particle of Ni. Furthermore, effects of additives to Ni cathode were studied and it was found that the electrolysis current could be much improved by addition of Fe to Ni. Effects of oxide ion conductor mixing with Ni–Fe were further studied and it was found that mixing La0.6Sr0.4Fe0.9Mn0.1O3 with Ni–Fe bimetal is the most effective for achieving high electrolysis current of CO2 of 2.07 A/cm2 at 1.6 V and 1073 K.
著者
宮入 裕夫 木嶋 芳雄 永井 正洋
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.4, pp.303-308, 2007-04-01 (Released:2009-01-30)
参考文献数
13
被引用文献数
3 3

This paper examined adhesive properties of steel coating alkid-melamine film (silica content 30 wt%) that has the relations between surface treatments of steel coating and thickness of steel coats. Especially we experimentally studied the influenced factors of adhesive properties between steel surface treatments and strength of coating film by using the interfacial cutting system (Saicas method).
著者
中村 修 山本 哲也 上野 和之 髙谷 幸司
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.101, no.2, pp.88-92, 2015 (Released:2015-01-31)
参考文献数
10
被引用文献数
6

Numerical simulation of lance-jet impinging on a liquid free surface was carried out and validated against the experimental data of Ueno et al. [Tetsu-to-Hagané, 101 (2015), 74]. Computational domain was separated to lance domain and water-bath domain. Lance domain was solved as single phase of compressible gas and the result was used to inlet boundary condition of water-bath domain by volume of fluid method (VOF) solver. Large eddy simulation (LES) was used and both solver are a part of OpenFOAM, open source CFD toolkit. The time average of depth and diameter of cavity was almost consistent with the experiment. The standard deviation was 10-20% of the time average and slightly larger than that of the experiment. Simulation showed that sloshing of water surface might enhance the spitting phenomena.
著者
Hirokazu Tsukahara Takuro Masumura Toshihiro Tsuchiyama Setsuo Takaki Koichi Nakashima Kazukuni Hase Shigeru Endo
出版者
一般社団法人 日本鉄鋼協会
雑誌
ISIJ International (ISSN:09151559)
巻号頁・発行日
vol.55, no.1, pp.312-318, 2015-01-15 (Released:2015-02-06)
参考文献数
26
被引用文献数
3

The range of chemical compositions that can obtain an austenitic single structure was defined for medium-manganese (Mn) carbon (C) steels. Among the potential compositions, Fe-5%Mn-4%Cr-(0.8–1.4)%C (mass%) was selected as the optimized composition range to form a stable austenitic structure. The tensile properties and deformation substructure were investigated in the austenitic steels having this composition. The work hardening behavior of the steels varied depending on the carbon content, which was closely related to the deformation microstructure. In the 0.8%C steel, both a deformation-induced martensitic phase as well as the formation of deformation twins generated a high work hardening until fracture. With an increasing carbon content, which increased the stacking fault energy (SFE), the deformation tended to shift towards dislocation slipping, resulting in a lower work hardening rate. This trend appears similar to conventional twinning-induced plasticity steel where the work hardening behavior is tied to the SFE.
著者
中川 祐介 多田 雅毅 小島 克己 中丸 裕樹
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.101, no.1, pp.40-45, 2015 (Released:2014-12-31)
参考文献数
20
被引用文献数
1 1

Fineness of ferrite grain is desirable for good surface quality of film laminated steel for drawn cans. And softness of steel is suitable for drawn cans from the view point of high formability. Generally, ultra low carbon steel (ULC) is soft, but it has coarse ferrite grains. On the other hand, low carbon steel (LC), which has fine ferrite grains, is hard and has poor formability, and therefore it is not suitable for drawing. In order to improve these contradictory properties, the amount of carbon and niobium in ULC steel is varied to control the size of precipitates of niobium carbide, which contribute to reduction of grain size. The study suggested that the newly developed steel has a potential to have an excellent balance of both properties.
著者
中山 武典 田中 秀和
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.9, pp.1089-1096, 2014 (Released:2014-08-31)
参考文献数
106
被引用文献数
1 8

Progress of corrosion science and corrosion engineering of steels has been reviewed. Case histories of atmospheric corrosion including research and development of weathering steels, and environmental degradation such as stress corrosion cracking, hydrogen embrittlement and corrosion fatigue of steels were explained in detail. Finally, future subjects that should be done for better understanding of corrosion and corrosion control of steels were proposed.
著者
大沼 郁雄 石田 清仁
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.9, pp.1050-1061, 2014 (Released:2014-08-31)
参考文献数
81
被引用文献数
2 2

The methodology of phase diagrams and that of alloy design were reviewed. The construction of a thermodynamic database for multicomponent systems by the CALPHAD method are shown, where the first principles calculations play a significant role in the estimation of thermodynamic properties of metastable phases. Some examples of alloy design for advanced materials using phase diagrams are shown in Pb-free machinable steels, high strength steels with low density, superelastic Fe-based and Cu-based alloys, magnetic recording media of Co-Cr-based alloys and Co-based superalloys.