巻号一覧
50 巻, 8 号
選択された号の論文の16件中1～16を表示しています
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藤田 譲, 野本 敏治, 長谷川 壽男1981 年 50 巻 8 号 p. 731-736
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThe residual stresses and deformations due to circumferential welds of cylindrical or spherical shells are one of the most important problems concerning to stress corrosion cracking and collapse strength of pipe structures or pressure vessels.
It is well known that the state of stress in butt-welded cylinder or sphere may quite different from that in butt-welded flat plate. This is because not only hoop stress but also bending stress in longitudinal direction is produced. This bending stress is induced due to the radial displacement caused by circumferential shrinkage of weld.
In this paper, welding deformations and residual stresses due to circumferential welds at the joint between cylindrical drum and hemispherical head plate is researched. One dimensional thermal elastoplastic analysis using Rayleigh-Ritz method is applied to the axi-symmetric thermal stress problems of comparatively thin cylindrical and spherical shells.
The following conclusions are obtained.
1) The influence of dimensions of shell and welding heat input on welding deformations and residual stresses can be described by means of the parameter (Q/h)β.
2) The effectiveness of the proposed design charts of the deformations and residual stresses for a given shell is confirmed by comparing the estimated values with the experimental results.抄録全体を表示PDF形式でダウンロード (1525K) -
佐藤 邦彦, 豊田 政男, 田中 清貴1981 年 50 巻 8 号 p. 736-743
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーTensile and bending tests have been carried out of surface-notched plates with particular reference to an applicability of fracture toughness parameters. Using the surface-notched specimens made from mild steels, observations are conducted of global and microscopic deformation of notched plate; in particular, crack opening displacement along notch front are paid attention. Fracture tests of specimens with a notch of which size is different have been also carried out under tension or bending.
In both tests, at first measurement procedure is settled of global strain which corresponds to global deformation. Fracture performance of surface-notched plates is affected by notch size; a considerable effect of notch depth under tention and notch length under bending on fracture strength can be observed. The distribution of COD along notch front is qualitatively consistent with it of stress intensity factor calculated by Newman et al. The point of crack front at which COD becomes maximum depends upon notch geometry and loading mode. In the specimens with deep notch under bending, in particular, that point is turned into the corner part of a surface notch.
In the specimens with part-through surface-notch, Kc-concept according to linear elastic fracture mechanics can be also applied for small scale yielding fracture. For general yielding fracture, δc-criterion according to the definition of the present paper can be effective.抄録全体を表示PDF形式でダウンロード (1756K) -
佐藤 邦彦, 豊田 政男, 南 二三吉1981 年 50 巻 8 号 p. 743-749
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーFracture toughness tests of specimens with mechanical and metallurgical heterogeneity along crack front have been carried out.
The main attention of the present study is paid to effects of fracture controlling factors such as fraction and location of embrittlement region in crack front on fracture toughness, in particular at cleavage crack initiation. Using specimens extracted from stainless clad steel and welded joint of HT80 steel, 3-point bending tests are conducted.
The deformation processes of specimens before fracture initiations are affected by neither mechanical nor metallurgical heterogeneity along crack front, and subsequent cleavage fractures initiate only in HT80 region regardless of its fraction and location in crack front. Cleavage resistances of specimens with heterogeneity along crack front are roughly equal to those of HT80 steel specimens. In the case that HT80 region is away from the center of thickness and exists only in vicinity of specimen surface, however, cleavage resistance of specimen is observed as apparently higher value than any other cases.
According to these results, fracture toughness values of specimens with heterogeneity along crack front in particular reference to cleavage crack initiation are evaluated as roughly equal to those of specimens filled with the lower-toughness material in crack front.抄録全体を表示PDF形式でダウンロード (1870K) -
信川 寿, 浜崎 正信1981 年 50 巻 8 号 p. 749-755
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThe bending fatigue tests of fillet weld joints of stiffened plate due to flexural vibration were carried out with T-type joint specimens of mild steel (SM41B) of 12 mm and 22 mm thick under constant amplitude loading conditions corresponding to two vibration modes in which the maximum dynamical stress works to the weld toe of the stiffened panel sides and to web side joint.
The weld toe and root fatigue strengths were evaluated by the local stress at weld toe and by the direct stress at root, respectively. The fatigue property of fillet weld joints with zero root penetration was appreciated by the initial threshold stress intensity factor range.抄録全体を表示PDF形式でダウンロード (465K) -
大嶋 健司, 安陪 稔, 窪田 武文1981 年 50 巻 8 号 p. 756-763
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThis paper deals with effects of power source characteristic on the stability of the drop transfer arc in a constant feeding speed system. The key to minute drop transfer is socalled "pinch effect" which automatically squeezes the drops off the electrode. The forced drop transfer is achieved by pulsing the current between the globular and spray transfer current ranges. Droplets are ejected one by one from the electrode tip at a regular frequency synchronizing with the frequency of current supplied from a power source with periodically varying nonlinear characteristic. Hence, with a sufficiently short arc, drop transfer is reasonably stable and associated with an absence of spatter. The forced transfer by drop mode may occur at average current levels far below the transition current.
The welding arc is described by nonlinear differential equations. The phase-plane analysis is used for the present investigation. The current and voltage of the arc constitute the coordinates of a representative point in the phase-plane. The behavior of the forced drop transfer arc is investigated by illustrating the geometrical configuration of integral curves in the phase-plane. When the current and length of the are keep on varying periodically in the steady state, the representative point moves along the limit cycle repeatedly. From the analytical results, it may be inferred that a nonlinear characteristic of power source is useful to stabilize the drop transfer arc.
Experiments are also carried out by making use of power sources which contain transistors and integrated circuits, and the forced drop transfer arc phenomena are observed by means of the high speed motion pictures. The validity of the theoretical results is confirmed by the experimental investigations.抄録全体を表示PDF形式でダウンロード (1861K) -
大径側に突出部を有する場合の摩擦圧接現象について沖田 耕三, 有年 雅敏, 平 博仁, 山田 桑太郎1981 年 50 巻 8 号 p. 764-770
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーJoint design of different diameter bar friction welding is important for reliability of joint performance and cost saving. And protrusion part from larger diameter bar, that diameter is the same as smaller one, is often prepared because proper friction welding parameter is said to be widened.
In this study, the effect of the protrusion on the friction welding behaviour was investigated.
The results obtained are as follows:
(1) The friction welding phenomenon of different diameter bar with protrusion remarkably depends on friction pressure, but not so on friction speed.
(2) When higher friction pressure was used, similar friction welding phenomenon as the same diameter bar welding was observed until collar from protrusion was restricted by larger diameter part, then burn-off rate decreased and temperature of friction surface rose. And phenomenon was close to that of different diameter without protrusion.
(3) When lower friction pressure was used, obvious change of phenomenon during friction welding was not observed.抄録全体を表示PDF形式でダウンロード (4634K) -
渡邊 之, 小嶋 敏文1981 年 50 巻 8 号 p. 770-778
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThis paper deals with the notch toughness of the weld metal produced by the large current MIG arc process in as welded and post weld heat treated conditions.
When one-run welding is made by tandem electrode process, cooling rate after welding for the trailing weld bead is retarded with preheating effect by the leading weld bead. This brings forth unevenly distributed notch toughness of weld metal, especially toughness degradation at and near the plate surface.
In previous paper, the authors have indicated the relation of notch toughness versus Ti and B and/or microstructure, which provides a guiding principle to solve those problems above mentioned. Based on the principle, an investigation was carried out to find out the optimum Ti and B contents of wire-consumable intended to use the longitudinal seam welding of heavy thickness steel pipe of arctic grade. As a result, the use of high Ti-B type wire-consumable as a trailing electrode was determined to be effective to improve the notch toughness of the weld metal at and near the plate-surface.
Nextly, in this paper, toughness degradation behavior of the weld metal due to post weld heat treatment was investigated. From various tests, it was observed the embrittlement depended upon cooling rate after heat treatment, the Mn content of the weld metal. The fracture mode of embrittled specimen was entirely intergranular one. And also, it was clarified that those behavior was reversible. These phenomena feature typical temper embrittlement. Furthermore these embrittlement was evidenced to be suppressed considerably by reducing the Mn content of wire-consumable.抄録全体を表示PDF形式でダウンロード (2198K) -
渡邊 之, 小嶋 敏文1981 年 50 巻 8 号 p. 778-786
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThis paper deals with the precipitation behavior of some microalloying elements in the weld metal during post weld heat treatment (PWHT).
An investigation was carried out to define the effects of Ti, B, Nb, V etc. on notch toughness of the weld metal which was produced by the large current MIG arc process. Attention was focused into three main areas as fo flows:
1. Correlation between toughness degradation attributed to PWHT and oxygen content of weld metal which governs the morphologies of Ti and B in the weld metal before PWHT.
2. A quantitative estimation of increase in hardness accompanied with toughness degradation which is attributed to the precipitation of Nb as NbC.
3. Determination of precipitation behavior of V existing solely or coexisting with Nb.
As a result, it becomes clear that the precipitation of Ti and B as carbonitrides during PWHT is not decisive of the embrittlement of the weld metal in the oxygen range above 200 ppm, where the larger proportion of both elements exists as oxides. The precipitation hardening of Nb as carbonitrides accompanied with significant toughness degradation reaches the maximum at 600°C in the PWHT temperature range from 500°to 650°C. On the other hand, the precipitation of V is suppressed when V coexists with Nb.抄録全体を表示PDF形式でダウンロード (2005K) -
Ti-B系溶接金属に関する研究(第2報)森 直道, 本間 弘之, 若林 正邦, 大北 茂1981 年 50 巻 8 号 p. 786-793
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThe effect of weld metal chemistry on the microstructures and mechanical properties of submerged arc welds has been studied. It was found that additions of Ti promote the formation of acicular ferrite to greater extent as compared with additions of other elements such as Mn and Mo, improve Charpy and COD properties of as-welded deposits and offer welds with quite homogeneous properties both in as-welded and reheated region.
Correlations were found among 0.25 mm COD transition temperatures Ti0.25, Charpy transition temperatures vTrs and tensile strengths σB provided that these test specimens were sampled from the same area and are eiven as follows:
[T0.25]as-weld=0.84vTrs+4.3σB-286, [T0.25]regeated=0.72vTrs+2.6σB-176
It was also found that N deteriorates Charpy and COD properties significantly and the deposits contained Ti-B provide a good tolerance to it. Among the deposits bearing Ti, the consumable types likely to give the best combinations of tensile strengths in the range 50-60 kg/mm2, Charpy and COD properties were proved to be those containing Ti-B.抄録全体を表示PDF形式でダウンロード (4760K) -
中山 繁, 山下 清司, 尾崎 弘憲, 服部 晃1981 年 50 巻 8 号 p. 794-800
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーArgon gas is useful for conventional gas shielded arc welding in air, but it is harmful to diver/welder's health in pressurized atmosphere such as underwater hyperbaric welding. Although helium gas is more expensive than argon gas, it is the safest among other inert gases in pressurized atmosphere. Accordingly, this report describes the effects of ambient pressure up to 10 kg/cm2abs., shielding gases and welding parameteres on welding arc behaviors in pressurized atmosphere, that is, simulated underwater hyperbaric welding.
The results obtained are summerized as follows;
1) Arc voltage during TIG, MIG and SMA welding becomes higher with an increase in ambient pressure.
2) Arc voltage during TIG and MIG welding with helium gas shielding is higher than that with argon gas shielding.
3) Arc voltage during TIG and MIG welding is elevated by an increase in welding current.
4) Penetration depth of welded bead becomes deeper as ambient pressure increases.
5) Number of short circuiting transfer per second during MIG and SMA welding increase with an increasing in ambient pressure when weldingparameters are the same.
* Kawasaki Heavy Industries, Ltd.抄録全体を表示PDF形式でダウンロード (5045K) -
佐藤 邦彦, 田村 屯, 大前 堯, 真鍋 幸男, 品田 幸三郎1981 年 50 巻 8 号 p. 800-806
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーAuthors have developed a new automatic welding system called "Locally Drying Underwater Welding" based on unique locallized dry environment by fluid curtain. For applying this process to steel structures, we have studied the cooling characteristic of this underwater weld to estimate the quality of a underwater welding joint.
The main conclusions obtained in this study are summerized as follows.
1. In case of high current and high speed welding, an underwater weld was quenched by water surrounding the welding torch.
But in case of low current and low speed welding, cooling characteristic was similar to that of an air weld.
2. In this method, the dependence of the maximum hardness of an underwater weld on the welding speed and heat input differed from that of an air weld. But the maximum hardness has good correspondence with cooling time from 800°C to 300°C.
3. Heat flow of underwater weld was investigated theoretically as the problem of heat conduction and heat transfer from an instantaneous plane heat source and results of experiments were explained clearly by this theory.抄録全体を表示PDF形式でダウンロード (496K) -
武田 俊一, 山田 桑太郎, 福永 功1981 年 50 巻 8 号 p. 807-814
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThis paper describes the weldability and shielding characteristics of ultra high strength steel for Deep Submersible Research Vehicle (DSRV).
10Ni-8Co steel is selected for the pressure hull of DSRV to be operated undersea 6000m in depth, that is a double quenched and tempered (aged) ultra high strength steel with proof stress above 120 kgf/mm2.
Generally, TIG welding is employed for this steel to obtain high strength and notch toughness. Besides this, it has been said that this steel is very sensitive to the contamination of various gas elements, and so perfect welding is required.
From this point of view, triple shielding type narrow groove TIG torch has been developed to satisfy that requirement, and performance test was carried out at various shielding conditions to investigate their basic properties and to confirm the effectiveness of that shielding equipment. The results obtained are summarized as follows;
1) Mechanical properties of weld metal are related to nitrogen and oxygen content of weld metal. 2) In the case of triple shielding method (Ar shielding gas), nitrogen and oxygen content of weld metal are as same as thorse of base metal.
3) It is confirmed that triple shielding type TIG torch is very effective to prevent the contamination of weld joint.抄録全体を表示PDF形式でダウンロード (425K) -
木原 博, 佐藤 邦彦, 遠藤 倫正, 広瀬 衛, 下山 仁一, 高野 元太1981 年 50 巻 8 号 p. 814-819
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーFor pressure hulls of Deep Submergence Vehicle (DSV) operating in seas of 2000 m depth, the most important point is the maximum load carrying capacity under the minimum weight. For this reason, spherical shell made of high strength steel is adopted for pressure hulls.
The authors investigated heat treatment conditions and GTAW welding conditions of HT 100 steel (5Ni-Cr-Mo-V QT steel with a yield strength of 90 kgf/mm2) in report. 1.
In this report, a procedure of decision of welding conditions for high strength steel like HT 100 is proposed. And using this procedure the full scale model of spherical pressure hull was fabricated. After completion of this model, the weld metal was proved to satisfy the requirements of the destructive and non-destructive tests.抄録全体を表示PDF形式でダウンロード (3488K) -
遠藤 倫正, 広瀬 衛, 豊原 力, 森鼻 英征, 渕上 勝人, 下山 仁一, 高野 元太1981 年 50 巻 8 号 p. 820-827
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーThe pressure hull for deep submersible has to cope with the tradeoff subject of the load carrying capacity and the minimum weight at the same time. For this reason, spherical shell has been normally adopted for the pressure hull. Besides this, high yield strength materials are used for it.
The authors have already confirmed that GTA welding is effective for the pressure hull of 6, 000 m class of 10Ni-8Co steel. However recently, electron beam welding, which has the possibility to reduce welding distortion in comparison with GTA welding, has come to withstand this objective.
The authors, in this paper, have established the effectiveness of the EBW for the pressure hull of 6, 000 m class of 10Ni-8Co steel.抄録全体を表示PDF形式でダウンロード (3129K) -
1981 年 50 巻 8 号 p. 828-838
発行日: 1981/08/05
公開日: 2011/08/05
ジャーナル フリーPDF形式でダウンロード (880K) -
1981 年 50 巻 8 号 p. 834
発行日: 1981年
公開日: 2011/08/05
ジャーナル フリーPDF形式でダウンロード (33K)
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