Abstract: An Al—Mg—Si series alloy ingot consisting essentially of Si:0.2-0.8 wt %, Mg:0.3-0.9 wt %, Fe:0.35 wt % or less, Cu:0.20 wt % or less and the balance of aluminum and inevitable impurities is prepared. The alloy ingot is homogenized, then subjected to rough hot rolling and finish hot rolling, and finally to cold rolling. One of the rough hot rolling is controlled such that material temperature immediately before one of the rough hot rolling is from 350 to 440° C., cooling rate between one of the rough hot rolling and rough hot rolling subsequent thereto is 50° C./min or more, material temperature immediately after one of the rough hot rolling is from 250 to 340° C. and plate thickness immediately after one of the rough hot rolling is 10 mm or less. The cold rolling is controlled such that rolling reduction is 30% or more.

Abstract: The present invention provides an abrasive composition for polishing magnetic recording disk substrates that results in a low surface roughness of the magnetic recording disk, allows the attaining of high-density recording without the occurrence of protrusions or polishing scratches, and enables polishing to be performed at an economical speed. The present invention discloses an abrasive composition for polishing magnetic recording disk substrates comprising water, silicon dioxide, antigelling agent, aluminum nitrate and hydrogen peroxide.

Abstract: A connecting device for a heat exchanger which has a fluid circulating channel formed with an opening at one end thereof and an opening at the other end thereof, the openings being formed as juxtaposed in one side of the heat exchanger. The connecting device comprises a blocklike connector body having two horizontal through bores corresponding to the respective openings and fixed to the heat exchanger with the through bores in coincidence with the respective openings. A tubular member is fluid-tightly fitted in each of the through bores and has a connecting end projecting toward a connectable device. The connecting end is in the form of a spigot fittable in a socket of the connectable device.

Abstract: A metal purifying apparatus comprises a closed melting furnace equipped with a heater, molten metal holding crucible disposed within the furnace, a vertical hollow rotary shaft penetrating through a top wall of the furnace, a packing sealing off a clearance in the shaft penetrating portion of the top wall around the shaft, rotary drive means for rotatingly driving the shaft, a hollow rotary cooling body fixedly provided at a lower end of the shaft and having an interior space communicating with an interior space of the shaft, and a cooling fluid supply source for supplying a cooling fluid to the interior of the cooling body. The rotary shaft has disposed therein a cooling fluid discharge pipe with a lower end positioned below the top wall of the furnace.

Abstract: A novel flux is provided for use in the low-temperature brazing aluminum materials of varied compositions, the flux being composed of a KCl--NaCl--BaCl.sub.2 base and 0.5-5.0 wt. % of LiF and/or 1.0-10.0 wt. % of ZnCl.sub.2 added to the base. A method of flux brazing a low-melting aluminum material is also provided, and the method is carried out by applying such a novel flux as well as a low-melting brazing agent to the aluminum material portions to be adjoined. The brazing agent is composed of an Al--Si--Zn alloy which contains 3-12% by weight of Si and 15-70% by weight of Zn.

Abstract: A stack type evaporator includes tubular elements 1 each having a plurality of inwardly protruding recessed ribs 7 which extend from an upper header portion 1a of the element to a lower header portion 1b, with the ribs serving as straight drainage canals 7a of specified width and area. A hydrophilic resin coating of a specific composition covers the outer surfaces of the tubular elements 1 and fins 2 each interposed between two adjacent tubular elements. The combination of straight drainage canals, the specified width and area thereof and the specific hydrophilic resin coating is effective to facilitate the drainage of condensed water so that the waterdrop is substantially prevented from flying out of the evaporator, and the hydrophilic coating itself does not emit any unpleasant smell.

Abstract: An improved cast ingot of aluminum alloy satisfactorily available for rolling operation containing Fe is disclosed which has no fir-tree structure or has only a very small region of fir-tree structure. This cast ingot of aluminum alloy contains calcium in the range of 0.0005 to 0.05% and has a grain size smaller than 150 microns in the region extended inward of a coarse cell phase on the surface area of the cast ingot, particularly in the vicinity of said coarse cell phase. The cast ingot is manufactured by way of the steps of addition of the above amount of calcium to molten aluminum alloy, supplementary addition of 0.005 to 0.1% Ti and 0.0001 to 0.02% B to the molten aluminum alloy and then continuous D.C. casting.