巻号一覧
49 巻, 2 号
選択された号の論文の6件中1～6を表示しています
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藤原 達雄, 加藤 哲男, 加藤 剛志, 大宝 雄蔵, 渡辺 貞幸1978 年 49 巻 2 号 p. 71-79
発行日: 1978/04/15
公開日: 2009/05/25
ジャーナル フリーWeldability of two kinds of molybdenum, electron beam melted molybdenum (EB-Mo) and powder metallurgy molybdenum (P/M-Mo), were evaluated by the tensile tests of specimens with fusion bead introduced by electron beam welder of accelerating voltage of 50kV and 150kV. Test material was sheet and plate of thickness 1mm and 5mm. EB-Mo exhibited good fusion weldability in comparison with P/M-Mo. The followings are the main results obtained:
1) EB-Mo showed the joint strength of 66kg/mm2 at room temperature in 1mm thick stress relieved sheet, whereas, P/M-Mo showed at most 32kg/mm2 with fully intercrystalline fracture surface.
2) Primary cause of the poor weldability in P/M-Mo in the occurrence of voids in weld metal, especially in the portion close to the boundary between parent and weld metal.
3) Secondary cause for the better joint strength in EB-Mo may be due to the scavenging effect of zirconium, which is added as a doping material in amount of 30 to 50ppm in order to enhance the softening resistance to annealing. Zirconium may, in combination with carbon which is another dopant, react with oxygen and nitrogen in the molten molybdenum and therefore suppress the grain boundary embrittlement due to segregation of oxygen and nitrogen.
4) Test results with 5mm thick P/M-Mo were poorer than 1mm P/M-Mo. EB-Mo did not show the dependence of weldability on the thickness of the sheet or plate.抄録全体を表示PDF形式でダウンロード (10620K) -
藤原 達雄, 加藤 剛志, 大宝 雄蔵1978 年 49 巻 2 号 p. 80-89
発行日: 1978/04/15
公開日: 2009/05/25
ジャーナル フリーElectron beam was applied to the industrial production of melted molybdenum doped with carbon and zirconium. The effect of zirconium doping was investigated down to the dilute amount of from 50 to 60ppm. The addition of zirconium in amount of the said ppm could raise the recrystallization temperature by 200°C while keeping the ductility good. The characteristics of this molybdenum, melted by 300kW electron beam furnace, was compared with those of powder metallurgy molybdenum in 1mm, 5mm and 12mm thick plate. Superiority of electron beam molybdenum doped with zirconium to powder metallurgy molybdenum was shown more clearly in thicker plates.
High temperature structural material should have good mechanical properties even in large sections as well as good weldability. The weldability of this electron beam melted molybdenum was reported in another paper. In these respects the electron beam melted molybdenum is expected to be utilized in high temperature technologies.抄録全体を表示PDF形式でダウンロード (5161K) -
加藤 哲男, 藤倉 正国, 矢萩 慎一郎, 石田 清仁1978 年 49 巻 2 号 p. 90-100
発行日: 1978/04/15
公開日: 2009/05/25
ジャーナル フリーEffect of heat treatment and deformation on permeability of non-magnetic high carbon and high manganese alloy RM711 are studied. The results obtained are as follows:
(1) The structure of the RM711 alloy is a stable austenite and the magnetic permeability is low even when RM711 is deformed at high strain.
(2) When RM711 is heated in the oxidizing atmosphere, low permeability is obtained between 700°C and 900°C, while the increase of permeability is observed below 700°C and above 900°C. The main cause of the increase of permeability is the formation of ferrimagnetic magnetite Fe3O4 below 700°C and the decarburized layer above 900°C.
(3) The decomposition of austenite of RM711 by isothermal treatment occurs below 700°C and the nose temperature is near 600°C. The increase of permeability is considered due to the precipitation of non-equilibrium cementite (i.e. soluble content of Mn in cementite is low) and ferrite.
(4) The reaction of decarburization can be explained by the diffusion of carbon in austenite. Permeability values change when the carbon content is less than 0.4% by decarburization.抄録全体を表示PDF形式でダウンロード (6046K) -
長崎 隆吉1978 年 49 巻 2 号 p. 101-107
発行日: 1978/04/15
公開日: 2009/05/25
ジャーナル フリーTogether with an explanation about the present situation of those developing projects being progressed positively in each country, the irradiation behavior, the important subject in developing researching of stainless steel and nickel alloy high-lighted as the fast breeder reactor has been described in this paper. Furthermore, mechanical properties, creep characteristics under irradiation, swelling phenomenon, considered as problems in material engineering, and also theoretical analysis concerning microstructure and irradiation are explaind hereunder with the estimation.
The material development for the fast breeder reactor has a direct connection with the completion of a nuclear fusion reactor in coming century and as far as development of atomic power material goes, no advancement can be made without solution of the problem in this field.抄録全体を表示PDF形式でダウンロード (460K) -
加藤 哲男, 藤倉 正国, 市川 二朗1978 年 49 巻 2 号 p. 108-116
発行日: 1978/04/15
公開日: 2009/05/25
ジャーナル フリーB bearing 18Cr-9Ni stainless steel is used for the neutron absorption material of nuclear power plant.
Some investigations on the effects of B addition on the 18Cr-9Ni stainless steel have been made and the following results are obtained.
(1) The crystal structure of boride is Cr2B type. More than 2.1% addition of B induces coarse primary crystals of borides.
(2) Cr content of boride is much higher than that in matrix. Cr content in matrix decreases to about 13% when 1.55% B is added.
(3) At the high temperature, deformation resistance is higher than that of 18Cr-9Ni alloy, but reduction in area does not change so much. When heating over 1200°C, reduction in area decreases rapidly for the partial remelting by eutectic reaction.
(4) By the addition of B, tensile strength rises but toughness decreases. Forged material has higher impact value than cast material, for example impact value of 1.55%B bearing steel is about 4kg·m/cm2.
(5) By the addition of B, corrosion resistance for nitric acid goes down. And corrosion resistance for hydrochloric acid and sulfuric acid goes down by the addition of 0.5%B but changes little by more addition of B.
(6) Welded joint by TIG welding is small in ductility, but has no welding defects. Joint efficiency of 1.27%B bearing steel is 84%.
(7) Drilling machinability with no lubricant is about 1/10 in tool life of the base 18Cr-9Ni alloy.抄録全体を表示PDF形式でダウンロード (7658K) -
福井 彰一, 杉浦 三朗, 上原 紀興, 三輪 守, 綱川 顕一1978 年 49 巻 2 号 p. 117-122
発行日: 1978/04/15
公開日: 2009/05/25
ジャーナル フリーMaraging steels with extremely low impurity level, especially in sulphur content, can be produced by plasma induction furnace (PIF). The sulphur content well below 10ppm can be usually achieved through refining in PIF from maraging steel scrap and or virgin material. Ultra low sulphur maraging steel thus produced shows considerably improved mechanical and environmental characteristics.
Emphasis should be placed upon the fact that the low sulphur maraging steel reveals several times longer life in delayed fracture test than the steel with usual level of sulphur content.抄録全体を表示PDF形式でダウンロード (351K)
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