著者

松本 和久 秦野 正治 大宮 慎一 藤井 秀樹

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.103, no.1, pp.54-63, 2017 (Released:2016-12-31)

参考文献数

40

被引用文献数

4 5

---

To investigate an effect of internal hydrogen on mechanical properties of a new austenitic stainless steel “STH2” having a nominal composition of Fe-15%Cr-9%Mn-6%Ni-2.5%Cu-0.15~0.2%N, tensile tests and fatigue crack growth tests were conducted for the specimens containing around 80 ppm hydrogen charged by the exposure in 45 MPa hydrogen gas at 300˚C for 200 h and the ones heat treated in air with the same heat pattern.At room temperature and –40˚C, no significant ductility drop by hydrogen charging was observed and about 80% of relative reduction of area was obtained, which is the same as that of JIS SUS316L with the same amount of internal hydrogen. In the specimens tensile tested at –40˚C, a small quantity of quasicleavage fracture surfaces were observed. In the banded areas in which Mn, Ni and Cu were negatively segregated, some relatively coarse voids coalesced with cracks extended along the maximum shear stress plane, which is similar to what is called void-sheet type of fracture. It is quite different from the case for tensile tests in 90 MPa hydrogen gas, in which coarse longitudinal cracks form, suggesting that the concentration of hydrogen at crack tips in 90 MPa hydrogen gas is higher than 80 ppm. It was also confirmed that fatigue crack growth rates were not accelerated by 80 ppm internal hydrogen although some faceted fracture surfaces composed of (111) γ formed.It is confirmed that STH2 has excellent properties not only in high pressure hydrogen gas but also in the circumstance of internal hydrogen of around 80 ppm.

著者

安藤 玲音 松野 崇 松田 知子 山下 典理男 横田 秀夫 後藤 健太 渡邊 育夢

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.106, no.12, pp.944-952, 2020 (Released:2020-11-30)

参考文献数

21

---

Herein, we investigated the local preliminary hardening of ferrite near the ferrite–martensite interfaces in a dual-phase (DP) steel. Geometrically necessary dislocations (GNDs), generated due to interfacial misfit between different phases, may cause preliminary hardening of ferrite around such interfaces. However, for nano-hardness distribution, the hardened zone was not evidently detected by scattering measurement. Thus, we factorized nano-hardness scattering to estimate the actual ferrite hardness near ferrite–martensite interfaces.First, nano-hardness was measured around a martensite island using a conical nano-indenter in the DP steel containing 10% martensite by volume. Taking into account the scattering, the nano-hardness measurement converged to the hardness of ferrite, exceeding the distance corresponding to the nano-indenter radius. Thus, a preliminary hardening zone was not detected. Subsequently, the surface of the nano-indented microstructure was polished and observed using scanning electron microscopy (SEM) by analyzing electron back scattering diffraction (EBSD). This analysis confirmed the presence of the nano-indented microstructure under ferrite. Moreover, it established that the majority of the irregularly higher nano-hardness was caused by the buried martensite under ferrite. The value of the kernel average misorientation (KAM), which is proportional to the GND density for other irregularly higher nano-hardness points, was higher for the nano-indented microstructure as compared to that of the buried martensite. On the other hand, the ferrite was expanded under the nano-indented points for the majority of the irregularly lower nano-hardness, with some exceptions. Further, soft martensite was observed to induce irregularly lower nano-hardness locally around the interface.

著者

石田 四郎

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.10, no.10, pp.10-48, 1924-10-25 (Released:2009-07-09)

著者

野田 龍彦

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.65, no.12, pp.1814-1815, 1979-10-01 (Released:2010-02-22)

著者

棗田 浩和 北原 周 橋本 俊一

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.9, pp.525-533, 2016 (Released:2016-08-31)

参考文献数

31

被引用文献数

9 14

---

Recently, 5% Mn steel has been focused on as one of the promising candidates for third generation AHSS by showing an excellent TS-El relationship. The excellent TS-El relationship is brought about by a large volume fraction of retained austenite through the enrichment of austenite stabilizing elements such as C and Mn in reverted austenite. The effect of the microstructure of mother hot band on the changes in microstructure and mechanical properties was compared with the intercritical annealing time in this study. The steel containing about 10% of retained austenite in a mother hot band exhibited a higher volume fraction of retained austenite and higher strength. On the other hand, the steel which did not contain retained austenite in a mother hot band exhibited excellent strength-elongation combination. The difference of work hardening behavior in these steels was analyzed and thought to be brought about by the difference of transformation behavior during deformation determined by the stability of retained austenite affected by Mn concentration.

著者

足立 吉隆 新川田 圭介 奥野 晃弘 弘川 奨悟 田口 茂樹 定松 直

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.1, pp.47-55, 2016 (Released:2015-12-31)

参考文献数

19

被引用文献数

6 6

---

Prediction of a stress-strain curve of ferrite-martensite DP steels was studied by a combined technique of Bayesian inference and artificial neural network. To screen a descriptor to be used for neural network analysis, material genomes such as volume fraction, micro-hardness, handle, and void of martensite phase, and micro-hardness of ferrite phase were examined by Bayesian inference. In a case of small data set, a machine learning method to predict mechanical properties reliably was proposed.

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

vol.103, no.8, pp.468-474, 2017 (Released:2017-07-31)

参考文献数

12

被引用文献数

1 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

嘉村 平八

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.17, no.2, pp.109-118, 1931

被引用文献数

2

---

Some years ago, the author has published on the foundamental investigation of the reduction of iron ores by hydrogen, on the Meiji Senmon Gakko Gahuho and the Journal of Iron and Steel Institute. In this investigation he made the experiment of reduction by hydrogen on the different kinds of ore, from 2, 000 to 5, 000 grams to investigate the properties of melted iron produced from the reduced iron. He determined proper temperature and time of the reduction in nearly industrial scale using the iron sands from Sanin and Kuji, and the iron ores from Taihei, Johole, Tochu, Ansan and the mill scales. The sponge iron after reduction was made as brickets under the pressure, 2 tons per square inch. From 1kg, to 1&middot;5kg. of the brickets is melted in an electric resistance furnace made by carbon-tube and cast as ingot. The phenomena of the melting was observed, and the degree of the reduction of phospkorus and sulphur was estimated, also, the impurities in the iron was analysed.<BR>The ingot iron obtained by the melting was forged after heating and compared the physical properties of the iron produced by different kind of ores<BR>Generally, it is known, in the blast furnace working, that nearly all the phosphorous in the charge is reduced and goes into the pig iron and it is impossible to remove the phosphorous into the slag. But, in this e all the phosphorous is not reduced on account of low temperature of reduction and the ureduced phosphorous which exist as its oxide is removed in the slag during the melting. It is recognized that the degree of reduction changes by the temperature of reduction. To confirm this phenomena, the high phosphorous iron ores, Taihei and Johole is reduced in different temperatures between 600&deg;C and 1, 100&deg;C and investigated the phosphorous content in the iron and slag obtained by the melting of the sponge iron to observe the influence of the temperature on the reduction of phosphorous.

著者

嘉村 平八

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.47, no.12, pp.1663-1664, 1961

著者

嘉村 平八

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.37, no.7, pp.394-396, 1951

---

The author proposes a process for making of pure iron by a duplex process of Bessemer converter and bigh frequency electric furnace as an economical induatrial process. The molten pig iron melted in a cupola furnace was blown in the basic or acid bessemer converter depending on the phosphorus content to eliminate the impurities. <BR>The carbon content in the blown metal was kept under 0.04 per cent. The refining of the blown metal was carried out in the high frequeney electric furnace with acid slag. The final metal obtained contained very small impurities and it is recognized that it is not difficult to make the carbon cont-ent of iron under 0.02 per cent and to deoxidize the metal by acid slag to obtain the pure iron with good mechanical properties.

著者

嘉村 平八

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.9, no.10, pp.699-708, 1923

被引用文献数

2

著者

嘉村 平八

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.8, no.12, pp.863-866, 1922

著者

嘉村 平八

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.10, no.7, pp.475-489, 1924

被引用文献数

1

著者

嘉村 平八

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.21, no.8, pp.643-655, 1935

---

The author has been published on the effects of phosphorus as to the mechanical and physical properties of iron on this journal, Vol. XVIII, No. 4. This is the contuniation. of the previous investigation. It has been known that the magnetic properties of the iron is remarkably effected by small amount of impurities in it and the superior magnetic properties is obtained to eilminate the impurities as lower as possible in its manufacture.<BR>The author incidently discovered, in an occasion of investigation of iron made by the process of hydrogen reduction, that the phosphorus in the iron improves the magnetic properties of iron-that is high permeability and low hysteresis loss.<BR>In this research, the magnetic properties of phosphor iron, containing lower than 1% P was investigated. When the amount of phosphorus in the iron is about 0&middot;7% the maximum permeability reached to 20, 000 and the hysteresis loss decreased to less than 1, 000 ergs. per sq. cm. per cycle; that is nearly correspond to three times in the maximum permeability and 60% in the hysteresis loss compared with the 3&middot;5% silicon-steel in the market. When the phosphorus content is more than 0&middot;5%, no ageing phenomena was obserbed. It was recognized that the proper annealing temperature exist by different phosphorus content to obtain best magnetic properties. In the investigation of the microscopic structure, the higher the phosphorus content in the iron the larger grain size was to be seen as in case of the silicon-steel, but it is not much remarkable when the phosphorus content reaches to more than 0&middot;5%. When the annealing temperature is raised to the recrystalized range which is seen from the constitutional diagram of Fe-P, the deleterious effects on the magnetic properties was observed.

著者

久保 裕也 丸岡 伸洋 佐藤 嘉将

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.9, pp.871-876, 2019 (Released:2019-08-31)

参考文献数

12

被引用文献数

3

---

Fundamental experiments were conducted with the aim of crude separation of the phosphorus contained in high-P iron ore prior to the ironmaking process. By reducing high-P iron ore with lime and graphite at an appropriate blending ratio and temperature, a reduction product was obtained consisting of a P-concentrated phase, metallic Fe with low P, and an Fe oxide-containing phase. The reduction product was pulverized by electrical pulse disintegration, and a magnetic separation experiment was performed for each particle group. As a result, 57.5% of the P contained in the reduction product was removed by removing particles of 250 μm or less. Samples simulating the constituent phases of the reduction products were synthesized and subjected to magnetization measurement. It was assumed that the Fe oxide-containing phase was paramagnetic and the P-concentrated phase was diamagnetic. We calculated the magnetic and drag forces acting on the paramagnetic particles in wet magnetic separation. When the magnetic field gradient was low, the magnetic forces acting on the fine particles were low, and attraction was difficult due to the drag force of water.

著者

小川 雄司 丸岡 伸洋

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.100, no.4, pp.434-444, 2014 (Released:2014-03-31)

参考文献数

92

被引用文献数

8 15

---

Progress of hot metal treatment technology in Japan and scientific researches which supported the technology are outlined.To meet the increasingly severe customer requirements for steel properties, integrated steelmakers developed technologies for purifying molten steel, centering on the divided refining process, consisting of hot metal treatment, BOF decarburization and secondary refining. The hot metal treatment processes were put into practice at almost all steelworks in the 1980 s.Since the 1990 s, all companies have improved and restructured the hot metal treatment facilities, aiming at not only improvement of refining efficiency so as to achieve a higher degree of purity steel with higher productivity at lower cost, but also reduction in slag volume with the environmental problems taken into consideration.The directions in which hot metal treatment technology is to be pursued in the future are also commented briefly.

著者

横井 龍雄 首藤 洋志 池田 賢一 中田 伸生 土山 聡宏 大村 孝仁 峯 洋二 高島 和希

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.5, pp.244-252, 2016 (Released:2016-04-30)

参考文献数

38

---

Dual Phase (DP) steel is used in automotive body parts for weight saving and crashworthiness, however there is an issue of DP steel in low stretch flange ability evaluated by hole expanding tests. In order to improve stretch flange ability of DP steel, it is important to estimate the damage of punching quantitatively and to clarify the change of microstructure before and after punching because the hole expansion ratio is decided in the ductility remained after pre-strain equivalent to punching. Therefore we tried to measure the damage of punching by unique techniques of Electron Backscatter Diffraction (EBSD), nano-indentation and micro-tensile testing and to observe fracture surface by Scanning Transmission Electron Microscope (STEM). Average EBSD-Kernel Average Misorientation (KAM) value and pre-strain damage have strong correlation, thus average KAM value can become the index of the damage. The nanohardness and tensile strength using micrometer-sized specimens increased with increasing average KAM value in the ferritic phase as approaching the punching edge. A shear type fracture occurred without necking in the specimen cut out in the area of the edge. The ultrafine-grained ferritic microstructure was observed in the sample cut out in the same area with STEM. It seems that the ductility loss of the punched DP steel was probably attributed to localized strain into the ultrafine-grained ferritic microstructure.

著者

絹川 虚舟

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.4, pp.453-454, 1960-04-01 (Released:2010-10-12)

著者

中島 一磨 小林 睦弘 磯部 浩一 渡辺 健彦 矢萩 正人 宮地 博文 望月 俊男 長谷川 晃

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.71, no.1, pp.139-141, 1985-01-01 (Released:2009-06-19)

著者

銅金 義一

出版者

一般社団法人 日本鉄鋼協会

雑誌

鐵と鋼 (ISSN:00211575)

巻号頁・発行日

vol.18, no.3, pp.261-271, 1932-03-25 (Released:2009-07-09)