巻号一覧
51 巻, 1 号
選択された号の論文の7件中1～7を表示しています
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斉藤 誠, 森井 廉1980 年 51 巻 1 号 p. 4-12
発行日: 1980/01/15
公開日: 2009/06/16
ジャーナル フリーProperties of ultra-low oxygen structural steels with oxygen content below 15ppm produced by combination of RH degassing and Ar gas shielded casting techniques were studied. The following results were obtained in comparison to steels produced by conventional process.
1. Drastic decrease is observed in occurence of macroscopic streak flaw. Smaller number of non-metallic inclusions leads to improved cleanliness.
2. Decreased scatter in chemical compositions enables more precise control of hardenability.
3. Fatigue endurance limit as well as rolling contact fatigue life is increased.
4. Cold forgeability is improved, hence lower probability of crack initiation.
5. No significant improvement in machinability is observed.抄録全体を表示PDF形式でダウンロード (924K) -
上原 紀興, 礒川 憲二, 田中 良治1980 年 51 巻 1 号 p. 13-18
発行日: 1980/01/15
公開日: 2009/06/16
ジャーナル フリーTo save energy for gas carburizing, the processing time should be reduced. So new processes have been explored desperately and high-temperature ones, especially vacuum carburizing, are regarded as most promising. On the other hand few works have been carried out on steels themselves, which are also able to reduce the processing time.
As is commonly known the higher carbon content in the steel results in the deeper penetration of carbon, and yet the higher hardness of the core and the larger distortion of the parts on quenching. And decreasing alloying elements to eliminate the latter reactions will generally shorten the case depth.
Still molybdenum addition in the adequate quantity to medium carbon steels was expected to meet the above requiremets. Upon this the influence of Mo content on the carburizing characteristics was investigated throughly and new Cr-Mo steels with medium carbon have been developed.
For example, 0.27%C-0.6%Mn-0.6%Cr steel containing 0.15%Mo shows enough case depth in the processing time 20% less than JIS SCr 420 (Cr steel corresponding to SAE 5120). This new steel has equivalent core-hardenability and tensile/fatigue strength to it.抄録全体を表示PDF形式でダウンロード (285K) -
上原 紀興, 礒川 憲二, 田中 良治1980 年 51 巻 1 号 p. 19-23
発行日: 1980/01/15
公開日: 2009/06/16
ジャーナル フリーA medium carbon (0.5wt%) steel containing 0.1wt% vanadium had been developed recently. Laboratry tests were carried out on this new steel normalized or as-forged under various conditions. The results obtained are as follows.
(1) The higher the austenitizing temperatures and cooling rates, the higher the hardness numbers of normalized steels.
(2) Results of tensile tests on as-forged steels are independent on forging temperatures.
(3) The higher the cooling rates, the higher the strength and ductility of as-forged steels.
(4) The tensile and fatigue strength of this new steel as-forged are comparable to those of S 45 C steel after hardening and tempering.
(5) The yield ratio and impact value of the above steel are lower than those of S 45 C steel after hardening and tempering.抄録全体を表示PDF形式でダウンロード (1384K) -
丹羽 祐久, 渡辺 昌征, 礒川 憲二1980 年 51 巻 1 号 p. 24-33
発行日: 1980/01/15
公開日: 2009/06/16
ジャーナル フリーAlloy-designing of a nitrocarburizing steel for crank shafts of automobile engines was studied in order to increase the fatigue strength.
This crank shaft has been made of a free-machining carbon steel, and it was required to increase the fatigue strength by 20%.
It has been known that fatigue strength of nitro-carburized steels was controlled by mainly surface hardness and case depth, so contents of Cr and Al were optimized in view points those two factors. Through the laboratory experiments, optimum compositions were determined as follows;
0.2%C-0.7%Si-1%Mn-1%Cr-0.15%Al-0.08%S-0.1%S-0.1%Pb.
This new steel was produced in an industrial quantity and practical properties such as hot-forgeability, machinability, fatigue strength of a crank shaft after nitrocarburizing and so on were investigated in an automobile producer's shop. As a result, the new steel was found to satisfy the above requirements.抄録全体を表示PDF形式でダウンロード (2167K) -
竹内 宥公, 洞田 亮1980 年 51 巻 1 号 p. 34-42
発行日: 1980/01/15
公開日: 2009/06/16
ジャーナル フリーCO2 welding has been used more and more because of the properties of saving energy and obtaining higher efficiency, but now there grow requirements for further reduction of spatter, improvement of bead appearance, increase of welding speed and elevation of quality of weld metal. MIG welding seems to be suitable for these purposes, but it has fatal demerit that blowholes generate so often.
It was thought that these requirements can be satisfied by combining of CO2 and MIG welding (MAG welding), so that an investigation was made about the effects of Ar-CO2 mixed gas welding on the usability and properties of weld.
The results obtained are as follows:
1) Generation of spatter becomes fewer when spray transfer occurs in MAG welding.
2) Spray transfer occurs when ratio of Ar in shielding gas is more than 70%.
3) It is necessary to make the ratio of Ar in shielding gas less than 85% so as to inhibit the generation of blowholes.
4) Frequency of short cricuit increases according to increase of ratio of Ar, but as the ratio or Ar becomes over 85%, it decreases.
5) Appearance of bead and mechanical properties of weld metal become better according to increase of Ar ratio in shielding gas.
By these results, it was concluded that Ar-20%CO2 mixed gas was the best for MAG welding. And it was understood that Ar-20%CO2 MAG welding had merits of CO2 and MIG welding and furthermore, it had special features better than those two welding.
Also, the electrode wires DD50A and DD50S were developed for MAG welding.抄録全体を表示PDF形式でダウンロード (1497K) -
木村 茂夫1980 年 51 巻 1 号 p. 43-50
発行日: 1980/01/15
公開日: 2009/06/16
ジャーナル フリーIn recent years, the automotive industry has been faced with a number of demands, for example, fuel economy, low noise levels, comfortable drivability, safety and low exhaust emissions.
In particular, since fuel economy is the most urgent problem confronting the automakers, down-sizing and lightening the weight of cars have been typical trends throughout the world.
In the future manufacturing technology and materials will become even more important.
Automotive companies are already working on new developments, that will meet these requirements.
This paper discusses the following subjects.
(1) Recent automobile trends
(2) Automotive materials-presend and future
(3) Notable future materials
(4) Future requirements for the steel used in manufacturing automobiles抄録全体を表示PDF形式でダウンロード (2094K) -
津田 一如1980 年 51 巻 1 号 p. 51-56
発行日: 1980/01/15
公開日: 2009/06/16
ジャーナル フリーFrom the view point of saving recources, the reduction of alloying elements, such as molybdenum (Mo), in steels is an important and urgent project.
Saving molybdenum in machine structural steels, especially in steels for automobile components, had not been achieved up to now, because Mo has distinct effects on structural steel properties, such as hardenability, case hardenability, temper embrittlement, softening on tempering and so on.
Recently Daido Steel Co., Ltd. has succeeded in saving Mo in Cr-Mo steels after metallurgical analysis on the effects of various alloying elements and through precisely controlled processing named “FINE METALLURGY”.
In this report, three new steels are introduced-a boron steel, which replaces medium carbon Cr-Mo high-strength steels, and a low molybdenum Mn-Cr and a Mn-Cr steels which replace Cr-Mo carburizing steels.抄録全体を表示PDF形式でダウンロード (297K)
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