著者

柴田 公博 岩瀬 孝邦 坂元 宏規 瀬渡 直樹 松縄 朗 Hobenard Hohenberger Mueller Matthias Dausinger Friedrich

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.21, no.2, pp.204-212, 2003-05-05

被引用文献数

4

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Welding of Al-Mg and Al-Mg-Si alloys was performed using twin spot beams formed with two Nd: YAG lasers for the purpose of reducing porosities and humping caused due to unstable phenomena of weld bead during welding of aluminum alloys. The relationship between the configuration of the twin spot beam and the quality of the weld beads was investigated using X-ray and high-speed camera observations of the keyhole shapes and weld beads. X-ray observation of the weld beads showed that beam distance had a strong influence on the amount of porosities. At a shorter beam distance, porosities were apt to occurred in the weld. The amount of porosities decreased with an increase of beam distance. Beam distance affects keyhole shapes. The amount of porosities was clearly related to the ratio of keyhole depth to keyhole opening. Larger keyhole opening and/or shallower keyhole depth, smaller amount of porosities caused by instability of the weld pool.

著者

大木 基史 武藤 睦治 大原 稔 高橋 雅士 石橋 達弥

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.16, no.3, pp.395-404, 1998-08-05

参考文献数

18

被引用文献数

8

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Two kinds of thermal cycle tests with short (10 min) and long (23h) holding times were carried out to investigate thermal cycling damage characteristics and thermal barrier property of thermal barrier coatings (TBCs). Surface cracks vertical to the coating surface were nucleated due to thermal stress during both the thermal cycle tests. Holding time had no significant influence on the surface cracking behavior. On the other hand, holding time had a significant influence on the thermal barrier property, which was degraded with increasing total holding time. The degradation of thermal barrier property was caused by the decrease in porosity and hence by the increase in density of ceramic layer.

著者

前中 浩 佐久間 正明 松岡 一祥

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.4, no.1, pp.95-101, 1986-02-05

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The stress relief phenomena in pre-loading on butt welded plates and the changes of material properties owing to the pre-loading were investigated theoretically and experimentally. A over-matching welded joint composed of a 50 kgf/mm^2 class weld metal by automatic CO_2 welding and a mild steel of 16 mm thickness was tested. The strain distributions measured by strain gages showed the same tendency to those calculated by FEM, under pre-loadings in directions perpendicular and parallel to the weld line. The perpendicular loading was superior to the parallel loading in terms of reducing the plastic strains caused of the stress releaving. Strain aging embrittlement of weld metal, HAZ and base metal obtained by 2 mm V notched Charpy test was quite proportional to prestrain, and significant difference among them could not be found. The equations for estimation of the brittle fracture initiation temperature were checked. The rise in the temperature caused by the pre-loading was less than that due to the weld residual stress. It was concluded that the effective pre-loading method recommended in the present paper was sufficiently safe.

著者

大橋 修 菅 誠一郎

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.10, no.1, pp.53-58, 1992-02-05

被引用文献数

8

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The purpose of this study is to investigate the effect of twist angle on tensile strength of diffusion-welded joints by using molybdenum single crystals with (121) and (025) surfaces. Relation between the twist angle and strength is tried to explain with the coincidence site lattice model and a theoretical model calculation. The results are as follows : Single crystals could be welded without recrystallization. Tensile strength of the joints depended on the twist angles. The joints with twist angles up to 10 degree were as strong as the base metal. In case of the twist angles above 10 degree, there were peaks in tensile strength of the joints around the certain twist angles where a number of common lattice points were formed at welding interface. From the calculation, it was shown that the binding energy between the crystals decreased with decreasing the number of common lattice points. Twist angle widths of peaks in tensile strength were estimated with the Brandon's equation.

著者

金 裕哲 李 在翼 猪瀬 幸太郎

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.23, no.3, pp.431-435, 2005-08-05

被引用文献数

13 23

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In order to predict the distortion generated by welding with high accuracy, distortion with fillet welding was measured by three-dimensional photographic measurement. Then, the experiment was simulated by three-dimensional thermal elastic-plastic analysis by FEM. The important matters that should be noted on predicting the distortion with high accuracy were shown by comparing with the results of the experiment and those of the analysis. The results of measuring temperature could be accurately simulated by non-steady state thermal conduction analysis based on FEM. In carrying out the elastic-plastic analysis, four conditions (equilibrium equation, constitutive equation, condition of compatibility and yield condition) should be satisfied. In welding, the temperature largely changed from a melting temperature to a room temperature. So, yield stress of materials largely changed, too. In particular, yield stress becomes about zero above 700℃. The analysis should be carried out under the yield condition that equivalent stress generated in temperature increment ΔT did not exceed yield stress of materials at high temperature above 700℃. It should be sufficiently recognized that the obtained results were not reliable if the yield condition was not satisfied. Angular distortion generated in fillet welding could be accurately predicted by regarding the weld metal as a deposited metal not assuming that a deposited metal zone was a simple triangle. Specifying an influence factor on longitudinal bending distortion was difficult because the absolute value was small. However, it was indicated that the reasonable result could be obtained by regarding the weld metal as a deposited metal because the absolute value of longitudinal bending distortion at pass (2) (the second pass) of which restraint was severer became smaller than that at pass (1) (the first pass).

著者

小林 明 栗原 摂 羽原 康裕 荒田 吉明

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.8, no.4, pp.21-27, 1990-11-05

被引用文献数

2

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The deposit characteristics of ceramic powder sprayed onto a substrate by the gas tunnel type plasma spraying apparatus were studied, and it was found that the special spraying distance L^* can be determined by the deposit characteristics. The relation between the deposit characteristics and the coating quality such as the Vickers hardness and porosity was discussed and it was clarified that the special spraying distance L^* governing deposit characteristics corresponded to the critical spraying distance L_c which indicated the largest distance in order to obtain the good coating quality.

著者

瀬戸 佐智生 松本 浩司 増山 智将 廣島 美佐 石川 博俊

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.16, no.1, pp.59-65, 1998-02-05

被引用文献数

1

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In this research, diffusion bonding of the intermetallic compound TiAl containing Fe, V, B and SACM645 steel was investigated. Relationships between strength characteristics and bonding parameters were analyzed. Main results obtained are as follows, (1) Direct diffusion bonding of TiAl and SACM645 was possible, high strength joints were obtained by selecting short bonding time with the bonding temperature in the range of 1223〜1283K.(2) In the bonding interface, two or three inter-layers were formed as diffusion process proceeded. Decarburized layer at the steel side, Fe-Al-Ti type layer and TiC layer at the TiAl side were formed.(3) High strength joints were obtained by suppressing the formation of TiC compound in the bonding interface and by controlling total width of inter-layers within 5μm.

著者

村田 雅人 向井 喜彦 田口 佳男 堀田 昌直

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.9, no.3, pp.134-139, 1991-08-05

被引用文献数

7

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Intensity of secondary electron induced by incident electron beam depends on a degree of inclination of surface. In the present work, 3-dimensional image for fracture surface was tried to constitute by applying this secondary elecron property with improved type SEM equipment which had four secondary electron detectors to remove a image distortion caused by observating direction. As the results, we could obtain 3-dimensional image and measured direction depth of fracture surfaces by real time treatment with 32 bit personal computer. In the case, the calculation time for one fractograph analysis was about only 5 minutes.

著者

中地 映司 池田 惣一 金 裕哲 中辻 義弘 堀川 浩甫

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.15, no.3, pp.535-540, 1997-08-05

参考文献数

7

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The dissimilar materials welded joints of high manganese non-magnetic steel/carbon steel(hereafter refered to as DMW joints), in which weld defects such as hot crack or blowhole are not found, were the good quality. Tensile strength of DMW joints was 10% higher than that of the base metal of carbon steel. In the bend tests, the DMW joints showed the good ductility without crack. Charpy absorved energy at 0 (℃) of the DMW joints was over 120 (J) in the bond where it seems to be the lowest. Large hardening or softening was not detected in the heat affected zone. Fatigue strength of the DMW joints is almost the same with that of the welded joints of carbon steel/carbon steel. As the fatigue strength of the DMW joints exceeds the fatigue design standard curve of JSSC for carbon steel welded joints, the DMW joints can be treated the same as the welded joints of carbon steel/carbon steel of which strength is lower than that of high manganese non-magnetic steel, from the viewpoint of the fatigue design.

著者

篠崎 賢二 羅 湘軍 有吉 秀文 黒木 英憲 白井 誠

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.17, no.2, pp.286-293, 1999-05-05

被引用文献数

11

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This study was carried out quantitatively to evaluate the hot cracking susceptibilities of various Ni-base superalloys and the effect of grain size on hot cracking susceptibility during laser welding. Ni-base superalloys used were Inconel 718,Inconel X-750,Inconel 617,Inconel 625,Nimonic 90 Waspaloy, Hastelloy X. The grain size of Inconel 718 varied from about 10 to 110 μm. In this study, the hot craking susceptibility was evaluated by a modified U-type hot cracking tester during CO_2 laser welding. Samples were solution heat-treated before welding and welded with laser powers of 3 and 5 kW and with a traveling speed of 0.5 to 3 m/min. The hot cracking occurring in the weldment during the bead on plate test was reproduced on the U-type hot cracking test. Consequently, the liquation cracking susceptibilities of various Ni-base superalloys decreased in the order of Waspaloy, Inconel 617,Inconel 718,Hastelloy X, Inonel 625,Inconel X-750 and Nimonic 90. Liquation cracking susceptibility of Inconel 718 increased with an increase in grain size.

著者

松田 福久 上山 智之

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.11, no.1, pp.95-101, 1993-02-05

被引用文献数

6

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Solidification crack susceptibility in partially-melted bead-on-plate laser beam weld metal of 6 mm trick 0.2C-1.8Ni-0.55Cr-0.2Mo low alloy steel has been investigated with change of S and P contents in steel using maximum 5 KW CO_2 laser facility beam welder. Effect of weld bead configuration and amount of S and P on crack length in crosssectional bead have been mainly investigated. Estimation of crack length in weld metal was tried by means of regression analysis of data, using bead configuration and impurities of S and P. Moreover, effect of restraint of weld bead during welding on crack susceptibility was investigated. Main results obtained are as follows ; 1) Weld bead configuration is gradually changed from winecup-type to well-type with changing to higher power and higher welding speed in laser beam welding (LBW) within the welding condition in this investigation. 2) With an increase in weld power and welding speed solidification crack susceptibility in weld bead is increased. 3) Solidification cracks have been seen both winecup-and well-type weld bead. However, the cracks were much more in well-type bead than in winecup-type bead in general. 4) S and P impurities in steel have a detrimental effect for the cracks. However, S is 1.8 times more detrimental than P according to statistical investigation. 5) According to statistical investigation the cracks increase with an increase in length of side wall fused and of d_<B1/2> (bead width in 1/2 penetration) 6) The equation which can estimate the crack length in weld bead is introduced from the statistical investigation using the factors of bead configuration and impurities (S, P) in steel. 7) The restraint of the specimen during welding increases the crack susceptibility in weld bead in comparison with the restraint free bead.

著者

太田 昭彦 渡辺 修 松岡 一祥 志賀 千晃 西島 敏 前田 芳夫 鈴木 直之 久保 高宏

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.18, no.1, pp.141-145, 2000-02-05

参考文献数

18

被引用文献数

22

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The fatigue strength of developed box welds was improved about two times of the conventional box welds. The improved welds used the low transformation temperature welding material which contains 10% Cr and 10% Ni. The expansion of the developed welding material was 0.55% due to the transformation from austenite to martensite. This expansion induced the compressive residual stress around welds. On low stress range condition, the stress ratio effect by this compressive residual stress avoids the fatigue crack initiation at the weld toe. On high stress range condition, the fatigue crack initiated from weld toe and the fretting was observed on the fractured surface. While in the conventional welds, no trace of fretting was observed.

著者

中村 照美 平岡 和雄

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.19, no.1, pp.44-53, 2001-02-05

被引用文献数

19

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Narrow gap welding (NGW) joints offers many advantages over conventional welding methods, such as good mechanical properties of joints, high welding efficiency and low residual stress. As the groove gap width becomes narrower, the arc heat input can be reduced and the merits in narrow gap welding increases more. Generally, GMA welding method has been never applied to less than 5 mm groove gap, because it is guessed that it is arc instability and lack of fusion at the groove bottom area occur. In this paper, first of all, arc behavior under narrower gap joints is discussed, and it was concluded that the arc in MIG arc welding irregularly perturbates up-to-downwards along the groove wall under less than 5 mm gap, but CO_2 arc was stable under narrower gap. Next, penetrations at the groove bottom area in CO_2 arc welding were discussed. Characteristics of bead formation phenomena in CO_2 buried arc welding of bead-on-plate were analyzed. From the results, the relationship between hydrostatic potential of molten metal and arc force corresponding with welding current was estimated. Furthermore, the width of gauging region of penetration by arc force was measured and the relationship between the melting width at groove bottom and welding conditions (welding current and welding speed) can be suggested. With these results, numerical simulation model was proposed and the optimum welding conditions to melt the groove bottom area sufficiently and to minimize heat input were searched by numerical simulation. And then narrow gap welding with 5 mm groove gap was carried out using these simulated welding conditions. In the experimental results, the weld bead was obtained without lack of fusion at groove bottom, but the convex surface bead was formed which is disagreeable in multi-pass welding. The new welding process was proposed from numerical simulations in order to prevent this convex bead and to obtain sufficient melting at bottom area. In the new process, the wire extension can be controlled by welding current waveform and then arc regularly oscillated up-to-downwards along the groove wall. In this arc oscillation, arc heating distribution along groove wall 1ed to both sufficient penetration at groove bottom and concave surface bead shape.

著者

吹田 義一 正箱 信一郎 佐藤 順子 黒川 哲平 高井 大輔 佃 芳行 寺嶋 昇 藤澤 正一郎 黄地 尚義 増渕 興一

出版者

社団法人溶接学会

雑誌

溶接学会論文集 : quarterly journal of the Japan Welding Society (ISSN:02884771)

巻号頁・発行日

vol.21, no.1, pp.33-38, 2003-02-05

被引用文献数

6 8

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As a welding method in space, the authors have proposed the GHTA (Gas Hollow Tungsten Arc) welding method in the previous papers, where some GHTA welding experiments have been conducted under the condition of low pressure (10^-2 Pa) and/or the micro-gravity. In the present paper, a feasibility study has been conducted whether the method can be used under such a high vacuum condition (10^-5 Pa) as on the space station orbit. As a result, it is made clear that the GHTA method is quite feasible under the high vacuum condition and its melting process strongly depends on the operating gas species such as Ne, Ar and Kr. Increasing the flow rate of operating gas decreases the mass of metal vapor from molten pool and the use of a heavy operating gas such as Kr also decreases the mass of metal vapor.