Abstract: This invention relates to a method of brazing while the thickness of the opening between materials being brazed can not be maintained constant or can not be adjusted in the appropriate range. In order to solve this issue the porous material of metals or metal alloys consisting of Ni, Cu, Ti, Al, Ag or W should be utilized. The metallic porous material is inserted into the brazing opening mentioned above by using the softness of it, and is made to hold the brazing solder and to reinforce the bonding part after brazing.

Abstract: The object of this invention is to have shorter sealing chambers (preheating chamber and gradual cooling chamber) located before and after the brazing atmospheric chamber, to make higher sealing of the atmosphere, and to prevent the scratch caused by the conventional curtains made of metal or others. In order for that, the structures made of steel or graphite are installed standing perpendicular to the moving direction on the conveyor belt which is circulating through the atmospheric furnace. And the bendable or flexible sealing materials are installed on the ceiling and on the right and left side walls of the sealing chambers (preheating chamber and gradual cooling chamber), which are located before and after the atmospheric furnace, into the above two chambers, and making these bendable or flexible sealing materials have rubbing contact with the above mentioned structures.

Abstract: When aluminium products are preheated in a preheating furnace up to about 500° C. before they are brazed with a flux in a heating furnace, a nitrogen atmosphere in the preheating furnace is made convectional by fans for improving heating efficiencies and also for having the oxygen which is brought into the preheating furnace as a disturbance thereof and scattered about in the nitrogen atmosphere, contacted to furnace inner walls of the preheating furnace which are made from carbonaceous materials, and reacted therewith so as to be changed to CO, resulting in keeping the oxygen concentration of nitrogen atmosphere low, whereby when the aluminium products are brazed by heating them in a continuous atmosphere furnace including said preheating furnace and said heating furnace, heating time thereof is shorten and the brazing is made more economically than before.

Abstract: In heat-treating a metallic alloy containing volatile metals such as zinc, manganese, chromium, aluminium, and so on in a tunnellike continuous furnace, argon is employed as a furnace atmosphere so that a pressure selectively produced by the argon atmosphere in the furnace is utilized for preventing the volatile metals from evaporating out of the metallic alloy during its heat-treatment. The argon employed as the furnace atmosphere and having a specific gravity higher than the air prevents also the air from entering into the furnace, and works also to purge the air which has happened to come into the furnace together with the metallic alloy, whereby the furnace atmosphere is kept constantly inert.

Abstract: A furnace to be heated to a high temperature which employs heating elements made from carbon or graphite. A longitudinal space within the furnace for accommodating said heating elements and a furnace bed for the transportation of articles to be treated through the furnace, is formed solely by blocks of porous carbon and without the emplyment of a conventionally prerequisite protective case. A pair of the heating elements extend along inner lateral walls of said space, facing to each other with the furnace bed therebetween, and have their electric terminals projecting through and outside of a bottom wall of the furnace.

Abstract: Method of brazing aluminum or aluminum alloy parts, using a flux which is made from an eutectic of BaCl.sub.2, NaCl, and KCl as a base, and one or more of fluorides as an activating agent. On account of the flux being not deliquescent, the brazing method can be carried in an atmosphere which is free from oxygen. Flux residues are easily removable in this invention.

Abstract: A method of brazing aluminum articles in a continuous furnace, to which a step for producing fluoride fluxes is incorporated. An aqueous suspension of KAlF.sub.4 is produced continuously and in situ in the system of the method by the reaction of starting materials, Al(OH).sub.3, HF, and KOH, and the suspension as it is produced or with the dilution by water is sprayed over the articles which move through the furnace.

Abstract: A furnace for heating steel articles and so on without oxidation and decarbonization. In the furnace, non-oxidation gas atmosphere with or without cementation characteristics is produced and regenerated by subjecting the air to carbon elements and heat at a reaction chamber provided within the furnace or closely thereto, and the gas atmosphere is circulated through a substantially closed circuit with the said reaction chamber connecting outtake and intake openings of the furnace.

Abstract: Muffle furnace having an elongated metallic muffle extending through several heating zones of the furnace. Temperature of muffle is measured at different parts thereof. In order to minimize the difference of temperature which causes the deformation of muffle, heaters of furnace are controlled coincidentally so as to compensate said difference.

Abstract: A furnace for the heat-treatment of metallic articles with a protective atmosphere such as a reductive gas mainly consisting of H.sub.2, CO, N.sub.2. Said protective atmospheric gas is made from LPG, LNG, urban gas and other raw natural gases which have been supplied into the furnace directly from their sources by heating them by heating elements within the furnace and simultaneously converting them by a plurality of catalytic means extending along said heating elements.