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Volume 32, Issue 2
Displaying 1-6 of 6 articles from this issue
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Yugoro Ishii1963 Volume 32 Issue 2 Pages 80-90
Published: February 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (14432K) -
Yoshio Ando, Tadato Fujimura1963 Volume 32 Issue 2 Pages 91-100
Published: February 25, 1963
Released on J-STAGE: August 05, 2011
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Katsunobu Yamaya, Tsuguyasu Wada1963 Volume 32 Issue 2 Pages 101-106
Published: February 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSEffects of preheat and annealing on the structure and properties of deposited metal and white iron layer in the heat-affected zone of cast iron welds were investigated with the single bead method by using commercial mild steel and Ni 55 electrode.
Bead-cracks by mild steel electrode were markedly decreased at preheat temperatures higher than 400°C. Microstructures also varied at this temperature, namely bainite was observed in the heataffected zone, and the deposited metal was changed from martensite to white iron. With increasing preheat temperature, penetration of deposited metal was increased, consequently carbon content of the deposited metal was increased. Bead-cracks were decreased with decreasing welding currents.
When preheat temperature was low, the hardness of weldment was increased by 300°C annealing in both cases of mild steel and Ni 55 electrode, because of the increase of retained austenite and the precipitations of carbide.View full abstractDownload PDF (4390K) -
Mechanism of PenetrationKeizo Ishizaki1963 Volume 32 Issue 2 Pages 107-115
Published: February 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe author has proposed the following mechanism of penetration in Chapter 3 of this report.
The contact line of a mother drop push-squeezed by the arc force recedes, leaving the base metal surface bare. Near the point where the contact line starts to deviate from the boundary line of the surface of penetration, a strong pulling force to counteract the arc pressure is developed and this is the greater, the larger the value of the angle of penetration θg. When the θg of exposed surface is increased through direct action of arc the exposed surface displaces itself, and a "Peripheral Penetration" is caused at the front portion of the surface of penetration through the joint action of arc and mother drop.
The theory was testified in this report through the observation of various patterns of penetration and other evidences. Existence of bare surface of mother metal during welding proved to be true, and the traces of direct action of arc were discovered as small concavities upon it. Although the proposed theory is satisfactory for the peripheral penetration, it is necessary to modify the theory in order to explain the "Central Penetration", which is the result of direct action of arc on the constantly exposed base metal without interference of the mother drop. And at the rearward portion of the peripheral penetration, indirect action of the liquid metal overheated by arc plays a significant role, which is also coupled with the oscillation of the mother drop.
It was concluded that the most essential factors to decide the type of penetration are arc force on the one side and interfacial tension and contact angle of the mother drop on the other, because the interaction of these forces determines the size of exposed bare surface and induces its oscillation around the surface of penetration.View full abstractDownload PDF (9781K) -
On Multiple Spot Welding, Spot Welding of Copper Alloys and of Titanium or zirconium to SteelsMinoru Okada, Shigeo Shin1963 Volume 32 Issue 2 Pages 116-129
Published: February 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn this study an investigation was made in many ways about multiple spot welding as a preliminary research of ultrasonic seam welding and about spot welding as to the relationship between aging phenomena and joining properties, and lining of titanium or zirconium to steel.
In multiple spot welding it is needlees to say that joining properties are affected by ultrasonic power, tip pressure, joining time, shapes of tip and head of anvil and so on, but under the same joining condition they are fairly affected by the pitch (distance from spot center to spot center) and directien of tip motion. Pitch should be chosen properly so that the part joined already may not be interfered by the next joining.
In the joining of Cu-Be alloy (2.1% Be) water cooled from 750°C to Ag-Cu Alloys (90, 75, 60 Ag), the best joining properties were obtained in the case of Cu-Be alloy aged at 350°C for 15 to 30 min.. In this case, tensile shear strength of joint was about twice as large as that of material (as received, 1/2H) to Ag-Cu alloy.
No good joining properties were obtained in the case of being aged at 350°C for less than 10 min. or at 450°C for 60 min..
Comparing the joining properties of a material (as received, 1/2 H) to the same one with that of a material water cooled from 750°C to the same one, the former was better.
About joining properties of Ag-Cu alloys, the one that contained more silver was better.
Joining titanium or zirconium to mild steel or 18-8 stainless steel could be made by choosing suitahie ultrasonic welding condition.
Under the same joining condition still better joining part can be obtained by electrolytically polishing or zinc plating that surface to be joined of mild steel or 18-8 stainless steel, or putting in silver insert.
Mild steel and 18-8 stainless steel of which structures were the more unstable showed the better joining properties.View full abstractDownload PDF (12944K) -
Masayoshi Ozawa, Toshikatsu Morita1963 Volume 32 Issue 2 Pages 130-137
Published: February 25, 1963
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIt is essential for the estimation of energy given to electrode of arc to know how much heat energy is included in the melted globule, which seems not to have ever been measured directly.
The calorimetric method is used for the measurement of heat involved in the globule from the melted electrode of arc. The heat quantity per unit weight of melted metal depends upon the apparent current density of electrode, having much more than the value corresponding to its melting point. With MIG welding method, the melted globule has the heat quantity 550 cal/g which is approximately equal to that at its boiling point.
The results are as follows ;
1) With hand welding method, the heat quantity in melted metal depends upon the apparent current density of electrode.
2) The heat quantities of melted iron and aluminium electrodes increase with apparent current density between 600 and 2000 A/cm2 but saturate over that, while in copper it is almost constant under 5000 A/cm2.
3) The heat quantity of iron anode metal depends upon the surface conditions, while that of cathode is almost independent of them.
4) The heat quantity of melted anode metal is generally higher than that of melted cathode metal, and their difference is 30-50 cal/g with MIG welding method.
5) With MIG welding method, the shorter the electrode extension, the higher the heat quantity is, and it approaches the value corresponding to its boiling point.View full abstractDownload PDF (528K)
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