巻号一覧
69 巻, 1 号
選択された号の論文の10件中1～10を表示しています
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論説
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木村 利光, 田中 秀明, 中村 貞行1998 年 69 巻 1 号 p. 7-15
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーThis paper attempts to clarify the mechanism of pitting fatigue, one of the contact rolling fatigue failures at tooth faces in a gear. Carburized and carbonitrided JIS-SCr420 steels with as-heat treated surface were tested by geared roller tester with a contact stress of 3.68 GPa and a slip ratio of - 40%. At the surface of the carburized specimens, nonmartensitic areas derived from low hardenability due to internal oxidation were worn and detached with increase in the contact rolling cycles. It roughened the contact track and accelerated main crack propagation. On the other hand, carbonitrided specimens with little nonmartensitic area on their surfaces showed higher pitting resistance than carburized ones. It was further clarified that the surface layer of carbonitrided specimen was strengthened not only by stress induced martensitic transformation but nitrides precipitation during roller contact loading.抄録全体を表示PDF形式でダウンロード (401K) -
松村 康志, 紅林 豊, 中村 貞行1998 年 69 巻 1 号 p. 17-25
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーThe effect of induction-hardened depth on torsional fatigue of hole notched specimens was investigated. The results are as follows. (1) Induction-hardened specimens show the best torsional fatigue strength when the effective case depth / radius ratio is about 0.5. (2) In the case of shallow case depth, the cracks initiate at the hardened / non-hardened boundary. On the other hand, the fracture of deeply hardened specimen originates at the surface layer. (3) The cracks initiate at the hole surface in the normal direction of principal stress, because the principal shear stress is smaller than principal stress at hole surface.抄録全体を表示PDF形式でダウンロード (178K) -
井上 幸一郎, 中村 貞行1998 年 69 巻 1 号 p. 27-34
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーInfluence of carbon, manganese, chromium, and vanadium contents on mechanical properties and microstructures of bainitic microalloyed steels are investigated. The fatigue limit of the bainitic steels were compared with the ferritic-pearlitic steels with smooth and notched specimens. The hardness are increased by increase in content of each alloying element. The carbon equivalent for hardness (Ceq) can be described by the following equation Ceq=C(mass%)+0.23 ×Mn(mass%)+0.26 ×Cr(mass%)+0.31 × V(mass%). Carbon, manganese, and chromium decrease toughness but vanadium improves both toughness and hardness. Additionally, vanadium is effective in improvement of 0.2% proof. This reason is estimated that microstructures of bainitic steel i.e. martensite-austenite constituent (M-A constituent) are refined by vanadium addition. The fatigue strength of bainitic steels with smooth specimen is lower than ferritic-pearlitic steels for the same hardness. However, it is higher in the case of notched specimen. This is because bainitic steels have better notch sensitivity.抄録全体を表示PDF形式でダウンロード (338K) -
次井 慶介, 中村 貞行1998 年 69 巻 1 号 p. 35-40
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーIt is still common to use HSS tools for broaching, gear shaping, and some other processes. Cutting speeds in these processes are very low comparing with other cutting processes, like turning and hobbing. Effect of S+Te and Pb on the machinability at this low cutting speed has been investigated. The results are as follows. (1) S+Te steel prolongs tool life by 3 times. (2) Interrupted cutting process prolongs tool life by about 1.5 times in all steel grades. Cutting temperature is very important to prolong tool life even at this low cutting speed. (3) Sulphides reduce shear stress and they act as lubricant between tools and works. (4) Pb doesn't have a special effect on tool life at this low cutting speed. Cutting temperature is too low to melt Pb.抄録全体を表示PDF形式でダウンロード (103K) -
木南 俊哉, 中村 貞行1998 年 69 巻 1 号 p. 41-47
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーThis paper deals with the effect of the tangential load on the contact stress distribution of the roller pitting test by two-dimensional finite element method. With increase in tangential load, the principal shear stress increases near the surface region and the depth of the maximum shear stress decreases. On the other hand, the effect of tangential load on the shear stress amplitude (the difference between the maximum τxy and minimum τxy at each depth) distribution is small. The tangential load in roller pitting tests was measured. Effect of maximum pressure and slip ratio on the tangential load is not so large and the ratio of tangential load to normal load is about 0.08. The change of the stress distribution by this抄録全体を表示PDF形式でダウンロード (197K)
解説
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岡田 義夫1998 年 69 巻 1 号 p. 49-56
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーAlong with the bigger than ever change in environment of automobiles in recent years, requirements for automobiles accordingly have become of multi-phases. With regards to cost reduction, that have been dealt as foremost important issue in recent several years, also been propelled with catch up by Asian countries and with progress of world wide car price cut, more efforts to further reduce material cost are needed. And, more and more important has become the measures for safety and environmental issues. In safety issue, the process of from accident to damage occurrence is divided into three steps ( foreseeing of danger, avoidance of the danger, and minimizing of damage), and each step is under development of new system for safety. In aspect of materials, from view point of minimizing the damage, sheet steel having high absorption of collision energy is highly needed for development, and at the same time making light weight vehicle is important to suppress weight addition due to safety measures. With regard to environmental issues, prevention of global warming due to CO 2 (to be coped with fuel efficiency improvement), and control of environmentally burdensome materials like lead and mercury can not be left only to automobiles, and must be coped with global level. In the present review will be described a microalloyed steel developed for crank shaft with aim of cost reduction, microalloyed steel for steering rack to be formed by machining, a gear steel resisting high face load, developed for size minimization and light weight to achieve fuel efficiency improvement, and a boron steel for high strength shaft, being selected from examples of the company. And with regard to control of抄録全体を表示PDF形式でダウンロード (136K)
技術資料
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紅林 豊, 中村 貞行1998 年 69 巻 1 号 p. 57-64
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーThe purpose of our research was to develop a new steel which keeps good cold formability without spheroidization annealing. Based on fundamental research about the influence of hot working condition and chemical composition on rolled bar hardness, Jominy hardenability, case hardenability, cold formability and mechanical properties, a new case hardening steel has been developed which can be forged without spheloidization annealing. The developed steel contains boron, and the silicon and manganese contents are less than conventional case hardening steel. The developed steel shows fatigue strength equivalent to the conventional case hardening steel and better toughness and machinability.抄録全体を表示PDF形式でダウンロード (204K) -
伊藤 幸生1998 年 69 巻 1 号 p. 65-67
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーBoron steels has been applied to automotive bolts because of its cost performance in place of medium-carbon Cr-Mo steelsAD Boron steel can reduce the cost of automotive bolts drastically through the simplified manufacturing process. A new boron steel has been developedAD The grain boundary has been strengthened by reducing phosphorus and sulfur and the fine grain size has been achieved by adding niobium element. Both of these effects enable the bolt to have properties which are equal to medium-carbon Cr-Mo steels in delayed fracture characteristics. The new boron steel has been applied to class 10.9 bolts.抄録全体を表示PDF形式でダウンロード (134K) -
中村 貞行, 秦野 敦臣1998 年 69 巻 1 号 p. 73-78
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーBased on fundamental study about the toughness of hot rolled microalloyed steels, a new steel composed of 0.4 % carbon, 1.10 % manganese, 0.5 % chromium and 0.15 % vanadium was developed. The steel shows high toughness and high proof stress after well-controlled hot rolling. The steel has properties equivalent to conventional quenched and tempered carbon steels which are used for steering racks of passenger cars.抄録全体を表示PDF形式でダウンロード (97K) -
森 達也, 長瀬 忠広, 秦野 敦臣1998 年 69 巻 1 号 p. 79-84
発行日: 2000/03/27
公開日: 2000/03/27
ジャーナル フリーControlled rolling of bars and wire rods of specialty steels is a rolling thermo-mechanical processing, and provides technologies to obtain superior property products with respect to in formability and toughness as hot rolled. There have been so far developed saving of normalizing and annealing, grain refinement, direct quenching, and microalloyed steels. Further, with recent combination with controlled cooling and alloy design, a more advancement in properties and extension of application are made. In the report will be summarized representative grades, aims, and rolling schedules for controlled rolling and cooling in the example of rolling facilities of Chita Plant in Daido Steel.抄録全体を表示PDF形式でダウンロード (140K)
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