巻号一覧
62 巻, 1 号
選択された号の論文の8件中1～8を表示しています
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雀部 実, 原田 衛司1991 年 62 巻 1 号 p. 4-11
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーIf reaction products of a steelmaking reaction are gaseous materials, then it is expected that refining limit of the impurity may be infinitesimal because the gaseous materials can be continuously removed from a reaction chamber. If halide can be produced in a steelmaking reaction, then the reaction product is the gaseous material.
First possibility of halide production in steelmaking process is discussed on the basis of the thermochemistry.
Then removal of Si and Cu in molten iron saturated with carbon is experimentally proved by using Cl2 or FeCl2.抄録全体を表示PDF形式でダウンロード (351K) -
出向井 登, 一柳 信吾, 芝田 智樹, 宮谷 仁志1991 年 62 巻 1 号 p. 12-22
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーA fundamental experiment concerning levitation melting was carried out using a 60kW-30kHz generator. A water cooled copper crucible, cold crucible, which enables levitation of metal was set in the induction heating coil.
Various kinds of solid spherical metals (aluminum, copper, stainless steel, carbon steel and titanium) were successfully levitated in a conical cold crucible. The levitation height of the metal was found to depend on the density of the metal and the electric power, but not to so strongly depend on the diameter and electric conductivity of the metal.
Some kinds of reactive and refractory metals weighing 60 to 160g were easily melted in a cylindrical cold crucible. The equilibrium temperature of molten molybdenum reached approximately 200°C above the melting point.
The cold crucible levitation melting technology is thought to be realized at an industrial scale in the near future.抄録全体を表示PDF形式でダウンロード (1894K) -
江川 修, 内藤 善博, 佐久間 仁1991 年 62 巻 1 号 p. 23-33
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーDaido Steel Shibukawa Plant has developed the melting process for Ni-based alloys, such as permalloys and heat-resisting superalloys, by Electric Arc Furnace (EAF) combined with Vacuum Ladle refining Furnace (VLF) and/or AOD.
Results obtained in the running operation are summarized as follows:
(1) Decarburization
The rate of decarburizing from liquid Ni-based superalloys in AOD process is proportional to fc (carbon activity coefficient in Fe-based low alloy steel) as well as Fe-based steel.
In case of Ni-Cr-C alloys, [C] can be removed to about 0.03% by O2 blowing in EAF in spite of high [Cr] content as 20%Cr.
(2) Nitrogen removal
The behavior of nitrogen removal in AOD process can be calculated by the sum of Ar gas volume and CO gas volume generated in decarburization as well as stainless steel. The rate of nitrogen removal increases with the increase of fN (nitrogen activity coefficient) in Ni-based superalloys.
It is also effective for nitrogen removal in EAF or VLF to use CO boiling caused by the decarburizing reaction.
(3) Merits of EAF melting process
Compared with VIF melting process, the production cost is reduced and the productivity is increased because of the high flexibility of this process.
The superalloys melted by this process are supplied as the electrodes for Electro-Slag Remelting or Vacuum Arc Remelting, and the ingots for forging and/or rolling.抄録全体を表示PDF形式でダウンロード (394K) -
中山 傑, 中坪 修一, 西村 司, 津野 雅英1991 年 62 巻 1 号 p. 34-41
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーDevelopment of technologies in stainless steelmaking by electric furnace since 1988 are discussed.
Those are bottom gas bubbling to obtain reaction between molten steel and slag, sealed melting for the better recovery of metal elements, and Cr-Ore injection for the reduction of raw material cost and control of silicon in molten steel.抄録全体を表示PDF形式でダウンロード (343K) -
中田 博也, 高橋 元1991 年 62 巻 1 号 p. 42-48
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーIn general, it is very difficult to avoid keen center segregation in high carbon steel during bloom casting.
M-EMS (Electro-Magnetic-Stirrer in Mold) was newly introduced to the bloom caster, besides existing two steps of strand-EMSs, at Chita Plant, Daido Steel, Co., Ltd. in June 1988, for the purpose of center quality improvement.
In this paper, the technology on center quality improvement and high speed casting of high carbon steel using three EMSs are discussed.
The results are summarized as follows;
(1) For steel of less than 0.6% carbon content, the introduction of M-EMS has contributed to the increase of casting speed by about 5% together with the quality improvement.
(2) Internal cracks which occur during high speed casting, due to the straightening of the unsolidified bloom core by pinch rolls at final solidification stage, have been successfully solved by optimum pressure control of the pinch rolls.
(3) For steel of 1% carbon content such as bearing steel, the center quality has been improved by optimiging the casting speed and EMSs operation.抄録全体を表示PDF形式でダウンロード (1095K) -
和泉 喜久磨, 佐藤 光彦1991 年 62 巻 1 号 p. 49-57
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーThe electric power control of the arc furnace is performed by a voltage control through changing the voltage tap on the furnace transformer and a current control through electrode position adjustment. In the arc furnace, current fluctuations are very sharp, because arc is struck against various shapes of material.
To raise or lower the electrode according to the rapid current fluctuations requires quick response and accurate and swift forward/reverse rotation switching ability.
Several electrode control systems were developed and designed to meet these requirements.
This paper will show the outline of each system.抄録全体を表示PDF形式でダウンロード (372K) -
中田 博也, 高橋 元, 天野 肇1991 年 62 巻 1 号 p. 58-65
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーIn recent years, customer's demands are getting more and more keen towards the diversification in steel grades and hence smaller lot weight. Those resulted in the reduction of number of sequence casting, higher tundish refractory cost and the increase of bottom portions, which are inferior in quality, in bloom continuous casting. To solve these problems, two key technologies, tundish recycle operation in hot condition and the tundish sealing have been developed in Chita Plant, Daido Steel Co., Ltd. They are summarized as follows;
(1) In order to avoid air penetration into tundish, it was very effective to purge within the tundish by Ar gas blow, coupled with perfect sealing. Oxygen inside the tundish atmosphere decreased drastically from 2.5% to 0.3%, and thus, the quality of bloom bottom portion has been improved.
(2) Tundish nozzle was modified in both design and material to solve the nozzle clogging and it enabled easy operation of tunidish recycling in hot condition.
As the result, sequence casting ratio (heats/TD) has been increased to twice and tundish refractory cost has been reduced remarkably.抄録全体を表示PDF形式でダウンロード (1468K) -
江川 修, 内藤 善博, 松淵 周司1991 年 62 巻 1 号 p. 66-72
発行日: 1991/02/05
公開日: 2009/05/25
ジャーナル フリーIn Daido Steel, high speed steel is remelted by the ESR process in order to improve the material property and tool life.
The electrode has been melted by the induction furnace and cast into the small and long ingot.
For the improvement of the productivity and for the reduction of the production cost, the EAF-LF-CC process of the electrode has been developed.
In this paper, characteristics of the new process and the quality obtained by this process are described.抄録全体を表示PDF形式でダウンロード (8345K)
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