Recently, in order to satisfy the increasing demands in atomic power industry, aluminium alloys are used in many parts of the reactor, e.g., the canning material of the fuel element, deuteriem vessel, reactor vessel, pipe-lines and so on. In thsoe cases high quality is required of their welding performance, porosity being one of the most important defects among those found in welded joints. Porosity in welds not only decreases the mechanical properties and corrosion resistance of welded joints, but seems to cause the activation of gases included in welds under the irradiation. The experimental resuts are as follows : 1) As the time after cleaning passed, the gas contents increased remarkably. 2) As heat input increased, the gas contents decreased in all plate thicknesses (6, 12 and 20mm). 3) The gas contents of preheated welds were than those of untreated welds. Above results agreed with the results of the X-ray measurement of porosity.
As stated in a previous report, when we used liquid purifiers consisting of ferric chloride or cupric chloride, chemical reaction to fix the phosphine was done by self catalizing action of mercuric chloride. Regeneration is made completely by dissolving the precipitate. Like these metals, tin has two valency, but if stannic chloride is used, purifying power is distinctly inferior to ferric chloride owing to insoluble H2SnO3 is formed. In this report, we determined the powers of nickel and zinc chloride which have one valency. According to our experiments, it is cleared that both chlorides have same purifying action. Oxidation and reduction of chloride can not be reported, but these powers are superior to mercuric chloride solution. When passing crude acetylene through the nickel or zinc chloride, we suggest the following chemical reaction may be proceeded. MCl2+PH3→M3P2+HCl Regeneration of power is regarded as following reaction. M3P2+HCl→H3PO4+MCl2+HCl The aqueous solution of alkaline earth metal salts is more stable than other salts, so that it is scarcely attacked by phosphine.
The phenomenon of wetting has generally three types, adhesional wetting, immersional wetting and spreading wetting. The degree of wettability are in general represented by θ, T cos θ or T (cos θ+1), but on soldering not only adhesional wetting but also spreading wetting is recognized as the very important factor. Author measured the spreading area and contact angle of Pb-Sn solders after solidification on copper plate and calculated the adhesional wetting and spreading wetting of Pb-Sn solders in molten state on copper wire with fluxes. 1) Spreading area of solder after solidification is greater in inorganic-flux than in organic flux and solder spreades largest on copper in a satulated aqueous solution of zinc-and ammonium chloride (eutectic), while smallest in a satulated alcohol solution of resin, and the solder of Pb 60% has the largest area. 2) The more the tin % is, the greater the adhesional wetting is. 3) Equilibrium contact angle of the solder of Pb 40% is minimum, and spreading coefficient is maximum. 4) The lower temperature of molten solder is, the greater the adhesional wetting and the spreading wetting are. 5) The contact angle of solder after solidification is smaller than liquid solder on copper and the minimum contact angle of solid solder occures in the solder of Pb 60% but the minimum contact angle of liquid solder in the solder of Pb 40%.
On the 2nd report was reported the wetting of the soft solder on copper. After solidification soft solder of Pb 60% on copper spreads largest, but the richer the tin is, the greater the adhesional wetting is, and the spreading coefficient of solder of Pb 40% is greatest, and the lower the heating temperature of solder, the more wettability. This report is a reasearch for the wettability on brass, Cu3Sn and Cu6Sn5. 1) Spreading area of solder after solidification on brass and copper is independent of its surface tension and depends only on the contact angle when the volume of liquid solder is very small and constant. 2) Spreading area of solder on Cu3Sn is greatest in the solder of Pb 60%, but solders on Cu6Sn5 inspite of the composition of solder spread almost perfectly and have not contact angle, therefore formation of Cu6Sn5 between copper, brass and solder have the important influence on spreading. 3) Wettability does not depend on the material soldered, brass and copper and the sorts of flux, but depends on the solders themselves. 4) Wettability of solders on brass is greater than on copper, but spreading area of soft solder after solidification on copper is greater than on brass. 5) The tendency of variation of sprcading coefficient by the composition of solder is some with the contact angle of liquid solder on copper and brass. 6) Wettability is greater in inorganic flux than in organic flux.
We recommend a convenient and easy way to judge or compare with propriety of arcing condition of coated arc welding electrode by using of critical arc length-maximum length of arc condition between base plate and electrode. Because, the statistical enough correlation could be found between the critical arc length measured and the sensuous evaluated marks of arc stability by many test welding operators. And the reproducibility of the critical arc length was enough obtained to be able to compare with these many coated type of electrodes marketed, practically, each other.
In our plant major part of finishing work of large steel casting except machining is effected by chipping which needs heavy labour, occupying considerable time. So we introduced carbon-arc-blasting process for large steel castings, which blow away molten metal by compressed air as rapidly as it is melted by carbon arc. This process promoted efficiency and reduced finishing costs of the fettling plant remarkably, and its special features are as follows: 1. Cracks caused by heat effect are never appeared in plain steel castings. 2. Alloy steel castings sensitive to cracks could be cut without the danger of cracking, providing a proper preheating is used. 3. Surface grade of the arc air blasted casting is far more smooth than gas scarfed one and almost equal to as cast surface. 4. Working efficiency of the process on the carbon steel casting is about eight times compared with the conventional process and shows it's superiority on the alloy steel casting especially for stainless steel.