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Volume 40, Issue 6
Displaying 1-9 of 9 articles from this issue
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Iwao Onishi1971 Volume 40 Issue 6 Pages 489-500
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
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Mitsuru Arii, Takashi Ogawa, Akira Matsui, Masao Sasaki1971 Volume 40 Issue 6 Pages 501-505
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
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Toru Tomoto, Akira Sakaguchi1971 Volume 40 Issue 6 Pages 506-522
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
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Yugoro Ishii, Tadao Onzawa, Nobuo Seki, Tuyoshi Yanagisawa1971 Volume 40 Issue 6 Pages 523-534
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThis paper describes an experiment concerning the process of explosive bonding. The process of collision of two metal plates and the metal jet in the space ahead of region of collision point was directly observed by high speed photographs using a flash X-ray and a streak camera.
A metal jet emits brillant light in the air, but in case of Al-Al, dark spherical portions are observed in the metal jet; they are considered to be drops of aluminum (Photo. 6, 7).
In the symmetric collision of same materials, the jet velocity νj is decreasing monotonously with the set angle a. However, since the velocity of collision point νc decreases more rapidly than the jet velocity νj the ratio νj/νc increases.
In the case of α=cont., the jet velocity νj decreases with the increase of the plate thickness and its density (Fig. 9, 11).
In the case of dissimilar metal bond, the direction of jet flow shows a tendnecy to be declined to the side of heavy density metal. This tendency of declination and velocity of jet seem to be introduced by light density metal (Photo. 10, Fig. 13).
In the case of the asymmetric bond, when the difference of density between two metals is small, jet flows along the flyer plate (Photo. 13, 14).View full abstractDownload PDF (12467K) -
Effect of Alloying Elements on Notch Toughness and Weld Softening in Single-Pass Submerged-Arc Weld Heat-Affected ZoneMakoto Sato, Hajime Nakasugi1971 Volume 40 Issue 6 Pages 535-551
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSExperimental studies were made on the effect of alloying elements on the notch toughness of singlepass submerged-arc weld bond and weld softening in heat-affected zone welded with comparatively large heat input, employing 2 mm V notch Charpy impact test and small size tensile test of a systematically prepared 80 kg/mm2 high tensile steel plate.
Notch toughness of weld bond diminished with the increase of heat input.
Alloying elements which reduce notch toughness of weld bond are carbon, nitrogen, boron and large quantity of titanium. Reducing the carbon content to less than 0.10% improves the notch toughness of weld bond greatly.
Alloying elements which improve the notch toughness of weld bond are nickel, silicon and small quantity of vanadium.
Increasing aluminium decreases the notch toughness of weld bond, but the results are quite contrary to those of duplicated weld heat-affected zone.
Manganese, chromium and molybdenum have slight influences on notch toughness of weld bond, presumably because of bainitic structure in weld bond.
Niobium up to 0.05% also has little effect on the notch toughness of weld bond.
Alloying elements which reduce weld softening are carbon, niobium, vanadium, chromium, molybdenum, nitrogen, aluminium, phosphorus and adequate quantity of silicon. Tensile strength of softened heat-affected zone is generally improved with the addition of secondary hardening elements.
Microstructures of weld bond were upper bainitic and no primary ferrite was found, but a complete lower bainitic structure was hard to obtain in weld bond with highly hardenable steels tested.View full abstractDownload PDF (4155K) -
Consumption CharacteristicsKohei Ando, Jun Nishikawa1971 Volume 40 Issue 6 Pages 552-562
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSAs to the consumption of tungsten electrode the following phenomena are observed.
The consumption of pure and thoriated tungsten shows a remarkable difference at arc starting as shown in Fig. 2. The explosive expansion of gas in intercrystal zone of sintered electrode is presumed as the main cause of the consumption at arc starting. Experiment shows the minimum consumption at 1.5% ThO2 content. Thoria acts to decrease the arc starting period of cold cathode state and at the same time acts to increase the number of sintered defects as shown in Fig. 3.
It is observed that the metal vapour in arc atmosphere little affects the consumption in stationary period, while iron particle spattered on the electrode acts to increase the consumption of electrode. Photo 5 shows a remarkable change of electrode shape when the electrode is contaminated by carbon vapour.
Oxygen and nitrogen affect also the consumption; the former decreases the surface tension and the latter produces gas holes in the molten electrode tip. See Photo XI .View full abstractDownload PDF (7585K) -
Michio Inagaki, Harumasa Nakamura, Kazuo Ei1971 Volume 40 Issue 6 Pages 563-572
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSOverlaid weld metals of austenitic stainless steel in a pressure vessel of power reactor are usually postheated for a long period of time after welding. The heat treatment is considered a kind of sensitizing and it is important to check the soundness of the weld metal after heat treatment, especially about the precipitation of carbides.
Investigation was made about the distribution of delta ferrite and its change by reheating, precipitation of carbides and their identifications, and sigma phase. The main conclusions reached from this study are as follows:
(1) Precipitation of delta ferrite from molten weld metal depends on solidification phenomenon. There was a small amount of ferrite near the bond or toe in which the local solidification time was short, comparing with other parts of weld metal. At no specific location ferrite was found due to macrosegregation or extremely rapid solidification.
(2) Shape and amount of ferrite were changed by reheating after solidification. Ferrite was extremely grown after heating at 1350°C for 15 sec. It was spheroidized by heating at 1200°C.
(3) There were five types of carbides developed after postheating: a) dot-shaped carbide, b) massive carbide, c) precipitated carbide mostly due to diffusion of carbon from base metal, d) lamellar carbide by eutectic reaction, and e) precipitated carbide due to tempering of martensite.
(4) The first two types of carbides were M23C6 type except for a relatively intense postheating of 700°C. A M6C carbide was detected with M23C6 carbide after postheating at 700°C. It should be noticed that dot-shaped carbides were linked to each other on an austenite grain boundary when there was no ferrite, and massive carbides co-existed sometimes with sigma phase.
(5) The fourth one, lamellar carbide, which had not been pointed out in previous study, precipitated on an austenite grain boundary near base metal after a fairly large extent of carbon diffusion from base metal. The eutectic phase was very soft and it would be a cause of trouble in a side bend test which is required as part of the procedure test of power reactor.View full abstractDownload PDF (10278K) -
Kohei Ando, Jun Nishikawa, Shigeo Igarashi1971 Volume 40 Issue 6 Pages 573-578
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn the behaiviours of magnetically driven arc in the pipe welding, the following phenomena are observed.
In early period of arc, in which the cold cathode state takes place, the cathode spot tends to move into the internal surface of the pipe due to the existence of an oxide film and the magnetic force acting on the component of the arc current, while the anode spot moves round smoothly on the pipe end from the beginning of arc initiation.
The experiment shows that the melting rate of anode is larger than that of the cathode. This is presumed to he caused by the cathode behaiviours above mentioned.
Fig.11 shows the relation of the arc current and the exciting current to obtain a uniform molten layer at the pipe end.View full abstractDownload PDF (3035K) -
Isao Masumoto, Koreaki Tamaki, Hisanobu Mine1971 Volume 40 Issue 6 Pages 579-585
Published: June 25, 1971
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSTwo layers-laminated plates of 2.5% nickel steel-mild steel and 9% nickel steel-mild steel were made by hot rolling. The relative thickness of the nickel. steels was varied from 0.1 to 0.6. And their impact and mechanical properties were examined depending on the relative thickness. The results obtained are as follows:
(a) The impact values of these laminated plates steeply increased with a small increase of the 2.5% or 9% nickel steel thickness as compared with the impact value of mild steel.
(h) The impact value of the laminated plate of 9% nickel steel is larger than that of stainless steel or 2.5% nickel steel.
(c) The tensile strength of the laminated plates linearly increased with an increase of the relative thickness of nickel steel, but their ductility had no linear relation to the relative thickness.View full abstractDownload PDF (2680K)
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