巻号一覧
38 巻, 12 号
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岡田 実1969 年 38 巻 12 号 p. 1276-1277
発行日: 1969/12/25
公開日: 2011/08/05
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1969 年 38 巻 12 号 p. 1278-1351
発行日: 1969/12/25
公開日: 2011/08/05
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益本 功, 篠田 剛1969 年 38 巻 12 号 p. 1352-1361
発行日: 1969/12/25
公開日: 2011/08/05
ジャーナル フリーFor the purpose of decreasing blowholes in aluminum weld metal, this experiment was carried out under the shielding gas of argon mixed with nitrogen and/or oxygen.
Results obtained are as follows:-
1) Blowholes in aluminum deposited metal by MIG welding can be decreased by adding nitrogen and/or oxygen to supplied argon gas. Minimum porosity is obtained respectively for mixing ratios of argon 50%+nitrogen 50%, argon 98.5%+oxygen 6.5% (bead on plate) and argon 98.5%+oxygen 1.5% (I-butt weld).
2) In case of argon and oxygen shielding gas, same spray transfer is observed by oscillogram as in the case of argon only, but under argon-nitrogen shielding gas metal transfer changes to short circuit type.抄録全体を表示PDF形式でダウンロード (6477K) -
高マンガン鋼レールのエレクトロガス溶接安藤 精一, 内田 彰, 木俣 登, 萩原 健三1969 年 38 巻 12 号 p. 1362-1371
発行日: 1969/12/25
公開日: 2011/08/05
ジャーナル フリーA prototype gas shielded arc welding apparatus for continuous automatic welding of austenitic manganese steel rail was built. This apparatus consists of the main assembly including abed, copper blocks and a torch-moving mechanism, the special torch, the controller for controlling the torch movement, the operating panel and the ordinary gas shielded arc welder. It is provided with a device for water-cooling the heat affected zone (HAZ) of base metal.
Using the above-mentioned apparatus, austenitic manganese steel rails were welded by gas shielded arc welding process. The materials and welding conditions adopted are as follows: Base metal; 50 kg/m PS type, Wire; 16 Mn-16 Cr, Dia.; 1.6 mm, Shielding gas; CO2-A (50-50%), Joint type; I-groove, Gap; about 16 mm, Arc voltage; 35V, Current; 475A (average), Procedure; automatic and continuous, Forced cooling of base metal; HAZ water-coiled during welding, the whole weld water-cooled after welding.
The bending test results on welded rails show that the values of maximum load and deflection are fairly good-76-83 t and 61-103 mm with head up and 73-77 t and 71-77 mm with head down respectively (span 1 m, load applied at midspan). Fracture invariably propagates through the HAZ within 15 mm of fusion line. In certain areas of HAZ, the impact values. are considerably inferior to those of base metal, but except in the cases where casting defects are present, they exceed 10 kg-m/cm2 (2U, 20°C), with considerable toughness retained.
Weld metal is almost free from such welding defects as cracks or blow-holes. Local high-temperature cracks may be observed in the HAZ.
Presence of such cracks seems to be practically harmless in general use but they should be minimized in welded rail joint.
Welding takes about 6 minutes, which is by far shorter than 4.5 hours needed for manual arc welding of Vee-groove joint.抄録全体を表示PDF形式でダウンロード (9768K) -
石井 勇五郎, 恩沢 忠男, 生沼 利亮1969 年 38 巻 12 号 p. 1372-1378
発行日: 1969/12/25
公開日: 2011/08/05
ジャーナル フリーThe formation of a fusion layer (or alloy) on the bonded boundary in explosive bonding was discussed in this paper. For various combinations of dissimilar metals made by explosive bonding, the constitutionn of fusion layer at an interface was determined by x-ray microanalyser, then this measured value was corrected using absorption coefficient, etc. and a true value of the constitution was found (Table 1).
Assuming that momentarily heat was supplied at the interface of dissimilar metals, successively these metals were melted by the conducted heat, and the rate of melted volume was given by the equation (calculated value A, Table 1).
m1/m2=√λ1c1ρ1/λ2c2ρ2 ⋅ c2(θm2-θ0)+Hm2/c1(θm1-θ0)+Hm1
λ; heat conductivity c; heat capacity ρ; density θm; melting point θ; room temperature Hm; latent heat
From the former equation, assuming that equivalent heat was generated in metals near the interface, the rate of melted volume of these metals was given by the equation (calculated value B, Table 1).
m1/m2=c2(θm2-θ0)+Hm2/c1(θm1-θ0)+Hm1
The averaged values (=A+B/2) of (A) and (B) well agreed with the measured values (Fig. 7).
The result showed that heat was generated at the interface and at the inner metal near interface by plate impact, then the heat was conducted and it melted these metals of interface.
Under combination of metals having a large difference of melting points, the melting point of layer was substituted for those of metals, so that the calculated value became equal to the measured value.抄録全体を表示PDF形式でダウンロード (2924K) -
溶融境界部におけるEpitaxial growthとクレータに形成するテンドライトの結晶学的性質仙田 富男, 松田 福久, 加藤 光昭, 中川 博二1969 年 38 巻 12 号 p. 1379-1384
発行日: 1969/12/25
公開日: 2011/08/05
ジャーナル フリーInvestigations have been made on the epitaxial growth of columnar grains in niobium and aluminum weld metals, and also on the crystallographic properties of dendrites developed in the weld crater. Conclusions obtained are as follows:
(1) It was confirmed by X-ray diffraction method that the columnar grains grew epitaxially in the weld metal.
(2) The weld metal in an aluminum single crystal grew in the same crystallographic direction as the original single crystal.
(3) A columnar grain had a single crystallographic direction, whereas the direction of growth changed gradually.
(4) Dendrites were observed in the weld craters of many metals. It was found that the dendrites in niobium weld metal grew in the direction of ‹100› regardless of the welding speed.抄録全体を表示PDF形式でダウンロード (6130K) -
鄭 世喜1969 年 38 巻 12 号 p. 1385-1390
発行日: 1969/12/25
公開日: 2011/08/05
ジャーナル フリーCopper-electroplating method reveals the microscopic strain distribution in the heterogeneous structure of welded joints under repeated stress. By this method the effect of microscopic strain concentration on fatigue crack initiation has been studied. The localized strain concentration was observed in such a coarse microstructure as a fusion boundary or columnar structure in weld metal. It has been revealed at low stress level, that the strain concentrates at the fusion boundaries or columnar structure, and that the strain concentration factor in these regions is about 1.4, while the value of concentration decreases with an increasing stress level, and then in the whole structure, i.e., parent metal, heat affected zone and weld metal, there is observed the same amount of concentration. Fatigue cracks at the low stress level are observed at fusion boundary or weld metal. At high stress level, on the other hand, they initiate simultaneously in three parts. Then it can be established quantitatively that the fatigue crack initiation depends only upon the local shear strain concentration.
To improve the fatigue strength of welded joints, it is very important to observe a successive deformation behaviour in the microstructures under fatigue. It may be considerd, therefore, that the electroplating method is a useful means for this purpose.抄録全体を表示PDF形式でダウンロード (4284K) -
1969 年 38 巻 12 号 p. Plate1-Plate4
発行日: 1969/12/25
公開日: 2011/08/05
ジャーナル フリーPDF形式でダウンロード (9110K)
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