巻号一覧
47 巻, 5 号
選択された号の論文の9件中1～9を表示しています
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岡田 明之1978 年 47 巻 5 号 p. 246-251
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーPDF形式でダウンロード (1515K) -
予防法に対する定量的検討井川 博, 中尾 嘉邦, 西本 和俊, 井上 倫人1978 年 47 巻 5 号 p. 252-259
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーIn order to prevent weld decay in SUS 304, several metheods have been recommended, namely, (1) to use extra low C steel, (2) to use stabilized steels containing Nb or Ti, (3) to limit the heat input in welding, (4) to post heat-treat to dissolve M23C6, and so on.
However, there have been few systematic investigations to determine the optimum condition in these methods, especially concerning (1) and (3). Consequently, only rough standards are given for the prevention methods even in present day.
In the previous report, authors have elucidated that the precipitation of M23C6 in HAZ of SUS 304 which causes weld decay can be predicted by applying the "additivity rule" which is translating rule from isothermal process to thermal cycle one.
In this report, this rule was applied to the intergranular corrosion in HAZ of SUS 304. Based on these results, it was quantitatively considered to elucidate the optimum condition concerning prevention method (1) and (3) for weld decay.
Experimental results obtained in this report are as follows;
1) The beginning time for intergranular corrosion occurred during thermal cycles can be calculated from TTS diagram by applying the "additivity rule."
2) The region where intergranular corrosion occurs in HAZ of SUS 304 during welding can be also predicted by applying the "additivity rule."
3) Based on these results, it was made clear that the limit of welding heat input and C content required to prevent weld decay can be predicted by calculation.抄録全体を表示PDF形式でダウンロード (3591K) -
浜崎 正信, 村尾 安一1978 年 47 巻 5 号 p. 259-264
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーAuthors have been developing a consumable electrode water jet technique and automatic oxy-arc cutting technique for the underwater cutting method. But the drawback of these cutting technique is that cut surface is to be re-machined by other cutting technique for welding, and therefore studied underwater gas cutting technique in order to obtain a cut surface which is able to be welded underwater without any post machining. results obtained are as follow;
(1) With use of water curtain nozzle, flame are well stabilized without use of air as a protecting gas.
(2) For the underwater flame ignition, the new method in which spark generates near nozzle using high frequency ionizer is developed with successful result.
(3) In the underwater cutting of 9 mm to 50 mm thick mild steel, cutting speeds are almost the same compared with surface cutting.
(4) Dross which attaches to bottom side can be removed easily light hammering.
(5) Cut surface is pretty, therefore underwater butt and fillet welding can be carried out as it is, and welds show satisfactory results抄録全体を表示PDF形式でダウンロード (7385K) -
被溶接材の温度分布の計算山本 利雄, 奥田 滝夫1978 年 47 巻 5 号 p. 264-269
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーTemperature distribution in seam welding is calculated assuming that the current path in a plate is one shown in Fig. 1 and welding current distributes uniformly in the current path.
It is made clear that the approximate temperature distribution can be calculated on the above men-tioned assumptions and that the contact resistance at the weld interface plays an important role in weld formation.抄録全体を表示PDF形式でダウンロード (2554K) -
石崎 敬三, 横谷 真一郎1978 年 47 巻 5 号 p. 269-277
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーIn the previous report, the author developed a new method to calculate the rippling pattern by means of the 'solidification equation, ' which was postulated to represent the balance of interfacial tensions at the edge of the solid- liquid interface. Furthermore in this report. he showed analytically that the simple harmonic standing wave of a molten pool can be reproduced in the bead ripple pattern in a scale of v/c (v; welding speed, c; velocity of surface wave of the molten pool, v/c<<1)), only when the mean liquid phase angle θ is 90 deg., and the liquid phase angle θ is always equal to the solidification angle φ. The bead height tends to decrease after each one cycle duration when the inclination angle of advancing solidliquid interface fi is smaller than 90 deg., even if θ=β and θ=θ. Therefore, in order to obtain the stationary flat bead, it is necessary for the molten pool to be of swollen shape, and mean the liquid inclination angle a must increase as β becomes smaller and θs of a material greater.
solidification equation γscosφ=γcosθ+γi
γs=γcosθs+rγi
θs; characteristic value of θ when φ is zero in solidification equation抄録全体を表示PDF形式でダウンロード (4927K) -
玉置 維昭, 益本 功, 高橋 庸一1978 年 47 巻 5 号 p. 277-282
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーThe shape of the shielding gas stream of CO2 arc welding was visualized by the television system combined with the Schlieren optical apparatus. Some factors, such as the diameter of welding nozzle, the flow rate of shielding gas and the velocity of wind blow which influenced the core region of shielding gas and also the shielding area on the base metal surface, could be examined by this method. Gas analysis of shielding atmosphere and X-ray inspection of weld metal were also carried out to confirm the results obtained by this method.
The following results were obtained.
(a) In the area where the core region of shielding gas could be observed by the method, an enough CC2 concentration was measured, which could prevent the porosity of mild steel weld metal.. And the minimum CO2 concentration for preventing the porosity was found to be about 95 vol%.
(b) An experimental formula, which included shielding distance toward the wind, crosssectional area of nozzle, shielding gas velocity (Vs) and wind velocity (Vw), was obtained. And the critical velocity ratio Vs/Vw, which was the minimum velocity ratio for preventing the porosity under the wind blow, was estimated as 1.62.1. The value was then confirmed by the X-ray inspection on the porosity of weld metal.抄録全体を表示PDF形式でダウンロード (1391K) -
溶接割れに対する検討佐藤 邦彦, 豊田 政男, 浮田 和明, 中村 明弘, 松浦 十四彦1978 年 47 巻 5 号 p. 283-288
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーIn field-welding HT 80 steel heavy plates with E 11016 type electrodes, preheating temperature around 150°C is usually required for preventing weld cracks. This makes it difficult physiologically for workers to do continuous welding works in the tunnel. Fundamental study made so far reveals that undermatching electrodes of lower NTS level than the base plates are effective to lower the preheating temperature required for preventing weld cracks without appreciable decrease in joint strength. In order to improve the environmental conditions mentioned above, therefore, the authors have undertaken to apply the undermatching electrodes to the circumferential welding of the penstocks being under planning.
Weld cracking tests of a HT 80 steel plate, 50 mm thick, were carried out with two types of electrode, AWS E 11016 and JIS D 5816. Susceptibility for root cracking in heat-affected zone of the first-pass welding was studied by the y-groove weld cracking test, and for weld metal cracking in multi-pass welds by H-type restraint test. Conditions of humid absorption in the electrodes selected and joint restraint severity were varied.
Test results obtained are summarized as follows:
(1) In the welded joint of HT 80 steel plates, both root crack along fusion line of the first-pass weld and weld metal crack in multi-pass welds are likely to occur. The undermatching electrodes lower effectively the preheating temperature required for preventing the root crack by around 25°C as compared with the E 11016 type electrode under the same hydrogen level.
(2) The weld metal cracking in multi-pass welds is not affected apparently' by joint restraint intensity.
(3) The undermatching electrode has been found so effective for preventing the weld metal crack in multi-pass welds that the preheating temperature required is lowered by around 75°C as compared with the E 11016 type electrode.抄録全体を表示PDF形式でダウンロード (1714K) -
小倉 信和, 安藤 柱1978 年 47 巻 5 号 p. 288-294
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーTo assess the degree of embrittlement in a transformed HAZ and the possibility of additional embrittlement caused by hot straining, brittle fracture initiation behavior from a notch of poor penetration in a weldment of HT 80 steel of 31 mm thickness has been investigated by measuring critical crack opening displacement (COD) at fracture. Three points bend specimens of 15 mm thickness were extracted from butt joint with weld defect of poor penetration, and the tip of the notch was located on a fusion' line in modified single=bevel joints, or, it was located on a weld metal in modified single-Vee joints. In these butt joints the degree of hot straining was altered by changing a intensity of tensile restraint in modified Lehigh restraint test specimens.
Heat input had large effect on the fracture toughness of fusion line, and reference temperature (Tr: critical COD of 0.25 mm) was markedly riled with increasing the heat input up to 42 KJ/cm. Fusion line and coarse-grained region of the HAZ was susceptible to hot straining embrittlement whereas the weld metal was not. The quantitative relation between the intensity of tensile restraint and the increase in reference temperature (ΔTr) was obtained. Small region ahead of the poor penetration in the joint of high tensile restrain received severe hot straining and showed high Tr temperature, and it was concluded that this severe hot straining was caused by restricting the free contraction of the weldments.
In the as welded and hot strained conditions, all the specimens with notch of poor penetration were more brittle than the specimens with fatigue pre-crack extracted from parent material, and thermal stress relief had disadvantage effect on fracture toughness of fusion line. In the most specimens extracted from modified double-bevel joints, crack propagated along fusion line.抄録全体を表示PDF形式でダウンロード (3806K) -
常温圧接に関する研究(第2報)大橋 修, 橋本 達哉1978 年 47 巻 5 号 p. 294-299
発行日: 1978/05/05
公開日: 2011/08/05
ジャーナル フリーThe object of this paper is to investigate the effect of surface treatment such as the sliding along the welded interface and anodic oxidation on cold welding of aluminum-aluminum and aluminum-copper. The following results were obtained.
1. The weldability of aluminum treated by anodic oxidation is superior to that by wire brushing.
2. Aluminum is easily joined with the increase of the thickness of the anodic oxidation film.
3. The sliding along the welded interface is useful for the improvement of welds. And there is the suitable range of sliding conditions such as sliding distance and applied load. It is easy to obtain the successful joint of copper to aluminum pipe, the jig being set around the conical tapered joint and pressing the pipes together axially to make them slide each other under the suitable pressure.抄録全体を表示PDF形式でダウンロード (1784K)
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