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45 巻, 3 号
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研究論文
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田口 一男, 工藤 靖, 増田 喜久男1973 年 45 巻 3 号 p. 175-182
発行日: 1973/03/25
公開日: 2012/09/21
ジャーナル フリーMechanical properties of normalized or normalized and tempered low carbon steel castings containing molybdenum, vanadium, niobium and boron were investigated for the purpose of developing steel castings suitable for welding into 70kg/mm2 class high tensile steel plates for the cast-weld construction of earth moving machinery. The results obtained are as follows;
(1) Molybdenum and boron added together were most effective elements for increasing strength, and some further increase in the strength was obtained by vanadium addition to Mo-B steel casting.
(2) The effect of niobium on the strength of Mo-B steel casting was less than that of vanadium. The increase of strength by niobium addition was more evident in the 0.10%C steel casting than in the 0.20%C steel casting. On the other hand, vanadium was more effective for 0.20%C steel casting.
(3) The yielding point and ductility of normalized Mo-B steel casting were very much increased by tempering. Tempering changed the microstructure from lathy ferrite to massive ferrite.
(4) The chemical analysis of newly developed weldable 70kg/mm2 class steel casting is as follows; C : 0.23%<, Si : 0.60%<, Mn : 1.00-1.60%, Mo : 0.15-0.40%, V : 0.05-0.15%, B : 0.0006-0.005%.抄録全体を表示PDF形式でダウンロード (1035K) -
鈴木 是明, 中田 進一1973 年 45 巻 3 号 p. 183-192
発行日: 1973/03/25
公開日: 2012/09/21
ジャーナル フリーIn order to clarify the sintering mechanism of chromite sands, microscopic observations of the specimens sintered in the laboratory were carried out.
The results obtained were summarized as follows:
(1) As the sintering temperature became higher, the average gap in the pure chromite sand grains became smaller, but, conversely, that of the chromite sands with concentrated impurities became larger while the number of gaps fell. The average gap in the usual chromite sand grains was nearly constant.
(2) The addition of chromite flour containing little impurities was effective in making a sintered body with smaller gaps.
(3) The higher the content of the impurities in chromite sands was, the larger the remained contraction rate of sintered specimens made of chromite sands was.
(4) When chromite sands were heated in the oxidizing atmosphere, Fe concentrated in the bonding area and the area became fat. The sintering of pure chromite sands progressed in this way.
(5) When the chromite sands and the impurities were heated, at first the impurities melted and filled the gap in the chromite sand grains, and then the chromite sand grains, and then the chromite sands and the impurities reacted and sintering took place. This sintering was considered to be a liquid phase sintering.抄録全体を表示PDF形式でダウンロード (1223K) -
大和田野 利郎1973 年 45 巻 3 号 p. 193-197
発行日: 1973/03/25
公開日: 2012/09/21
ジャーナル フリーIt is well known that the graphite nodule number in malleable cast iron is an important factor in determining the graphitization rate. Methods of computing the nodule number per unit volume from the number and size of their intercepts per unit area are established, although they are rather complicated. In this paper an attempt is made to derive a mathematical formula for computing graphite??nodule number per unit volume of spheroidal graphite and malleable cast irons, the results of which were examined in comparison with the experimental data.
The results obtained are summarized as follows:
(1) Graphite nodule number per unit volume, NV, is related to the number of their intercepts per unit area, NA, by
NV=(π/6VG)1⁄2 (αNA)3⁄2
where VG denotes the volume fraction of graphite??nodules in the iron, and α3⁄2 the factor which depends on the distribution of the nodules.
(2) α3⁄2 ranges from 1.0 to about 1.4 for ordinary distribution of graphite nodules.
(3) NV-NA relationship written above is verified by the experimental data to be valid for spheroidal graphite and malleable cast irons.抄録全体を表示PDF形式でダウンロード (531K) -
二宮 三男, 野崎 佳彦1973 年 45 巻 3 号 p. 198-202
発行日: 1973/03/25
公開日: 2012/09/21
ジャーナル フリーFluidity of carbon steel, 13%Cr stainless steel, 18-8 stainless steel, high manganese steel and die steel was tested using spiral type test pieces. And thermal analysis was conducted for each steel to examine its relation to fluidity. The results obtained are as follows:
(1) The standard pouring temperatures which were obtained in these fluidity tests were 1,560°C for carbon steel, 1,540°C for 13%Cr stainless steel, 1,500°C for 18-8 stainless steel, 1,475°C for high manganese steel and 1,540°C for die steel. But since the 18-8 stainless steel castings are apt to have cold lap or cold shut defects on the surface, the actual pouring temperature should be raised about 50 degrees.
(2) The needed degree of superheating, which is the difference between the standard pouring temperature and the liquidus, varied among these cast steels. The more the solidification range of cast steel was, the more the needed superheating degree was. So it can be said that the fluidity of these cast steels was in inverse to the solidification range.
(3) The effect of the variation of pouring rate on the flow length was checked in carbon steel. The effect was prone to occur in low pouring temperature. But the present fluidity test had enough accuracy with careful pouring.抄録全体を表示PDF形式でダウンロード (621K) -
牟田口 元堂, 照沼 登1973 年 45 巻 3 号 p. 203-208
発行日: 1973/03/25
公開日: 2012/09/21
ジャーナル フリーIn furan bonded sand molds, iron oxide has been added to prevent the cementation of furan resin to cast steel. In this paper, the behavior of the iron oxide in pouring in furan bonded sands molds was studied. The structure of iron oxide was identified by the X-ray diffraction method and the composition of gases thermally decomposed from furan bonded sands was analysed by a gas chromatograph.
It became clear that the main effect of iron oxide in preventing the cementation of furan resin was in the catalytic acceleration of the thermal decomposision of furan resin.抄録全体を表示PDF形式でダウンロード (602K)
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