JP2007533466A - In-furnace brazing process - Google Patents

Abstract

  Brazing a metal member, at least one of which has a tubular shape (3), into the furnace which comprises a brazing material (5, 6, 18), preferably having a pre-shaped shape, inside the tubular member. It consists of the steps of reheating the interior of the furnace to position, melt the braze and create a bond. The process is particularly suitable for the construction of towel rack radiators.

Description

  The present invention is a brazing process, particularly a process of brazing elements that are difficult to process from the outside, such as a tube, and more particularly, combining elements that constitute a "towel-rail" type radiator. It relates to a brazing process. Preferably used in the process is an in-furnace brazing process.

  Brazing is generally a system used to permanently bond two metal parts (eg, non-ferrous or ferrous metal objects such as steels of various carbon contents). The bonding of the two members is made by a thin layer of metal, and the metal is a different material than the two members bonded together, which is called a weld metal or brazing material. The brazing material has a lower melting point than the material to be bonded, and the brazed area is at a temperature at which the brazing material melts. In general, the molten brazing material penetrates into the gap between two members joined together by capillary action and forms a bond by forming a layer and solidifying.

  There are two main techniques for brazing: torch brazing and in-furnace brazing. They differ in the method of supplying heat to dissolve the brazing filler metal. That is, in torch brazing, the bonding area is heated directly and locally, and a brazing material is placed there. In contrast, in-furnace brazing, after the brazing material is installed in the joining area in an appropriate manner, the members to be joined are introduced into the furnace. Inside the furnace, the members are heated to a temperature at which the brazing material melts. Heating is performed in stages, and it affects all members being joined, not just the areas affected by the joining. Cooling is also typically performed in stages, which is also done to prevent stress and damage on the components being processed. The furnace consists of several chambers into which the components to be processed are conveyed by a conveyor belt or other type of suitable mechanical means suitably configured to resist heat. .

  There are various systems for positioning the brazing material in place. For example, there are metal wires that are appropriately folded to fit the local features that can be used. Alternatively, a paste made of metal powder mixed with an appropriate binder is generally used. In practice, in many cases, the coupling structure does not allow for the precise positioning of the wire-shaped brazing material.

  Brazing is applied in the field of joining tubular elements together, for example when joining one pipe to another pipe or another type of element, for example a closure stop for both ends of the pipe. Used. In this case, a liquid tight bond is achieved. Special applications are made in the manufacture of towel rack radiators, which are commonly used in home heating. This type of radiator typically consists of two tubular manifolds in parallel, which are connected laterally by a series of tubes (typically forming a ladder-like structure). That is, a liquid, usually water, enters from one end of the manifold and circulates through the transverse tube before exiting from the opposite end of the other manifold. The important point when brazing is to seal the liquid so that it does not leak, but to connect the tube to the manifold, and the manifold has appropriate stoppers at both ends (a metal plate with the appropriate shape). It is sealed by. In metal radiators, copper-based pastes are commonly used, which are applied from outside the joint, and then brazing is performed in a furnace. The process is not sufficient for various reasons: That is, in order to achieve an average distribution, it must be possible to distribute the brazing material throughout the joint and it is difficult to position the brazing material in the correct manner. This operation is usually done manually by the operator and is therefore not reproducible, so the metal can be over-applied, resulting in wasted material and irregular surfaces, in many cases, Bad diffusion occurs throughout the joint. This results in a significantly higher probability that improper products are produced (often due to improper liquid sealing). Positioning from the outside also involves the possibility of the molten brazing material dripping, thus damaging some parts of the furnace such as the conveyor belt.

  The use of a welding paste is usually preferred to overcome positioning difficulties and is necessary when placing a stopper on the manifold, but it does present impurities such as leaving carbonaceous residues. And the quality of the bond is degraded during or after brazing. In addition, the paste-like metal is inevitably required to be thinned when used as a binder, so that the concentration of the metal is reduced in the relevant region in close proximity to the bond and the metal is formed during the bond formation process. The dispersion of becomes intense.

  Welding pastes, in addition to all the above pastes containing different metals, are expensive to manufacture and depending on the metal contained, the costs can be substantial. Since they are made by a manufacturing process involving special machinery, it is generally required to choose from those available on the market, and often it is very costly to produce a paste with a non-commercial composition Thus, the width of the metal-containing composition is reduced and the choice of brazing material is limited. On the other hand, usable metals (including powders or alloys) generally have high quality standards and are of high purity with a wide range of compositions (eg, metal wires). Or in the form of metal powder).

  The above problem is a brazing step of joining two metal members, at least one of the metal members being tubular, and positioning the brazing material on one of the metal members; Positioning the members relative to each other and heating the metal member to a temperature at which the brazing material can be melted, the brazing material prior to melting, the tubular metal member It is solved by a brazing process characterized by being positioned inside.

  According to a preferred embodiment of the present invention, the heating is performed in a furnace.

  According to a further preferred embodiment of the invention, the brazing material is in the form of a molded article, which may be molded, for example, in a suitably held metal wire or in a suitable shape, for example a thin ring.

  According to a particular aspect of the invention, the members to be joined are metal members of a towel rack radiator. For example, it may be a tube brazed into a tube and tubular manifold and a hole in one of the side surfaces of the manifold that is preferably flat. A stopper may also be coupled to one end of the manifold to close the manifold. In this case, according to a preferred embodiment of the present invention, the stopper has an outer periphery that is substantially the same as the shape and dimensions of the outer periphery of the manifold. According to another preferred embodiment, the stopper has a step on the inner surface (once the bond is made and faces the manifold), the outer edge of which can enter the interior of the manifold. And a suitable gap that is open enough to create a bond for brazing between itself and the interior wall of the manifold. The stopper has an internal surface on the surface that contacts the joint to be brazed, for example, if present, the surface that forms the joint that is brazed with the manifold Means are provided for holding the brazing material in the shape of a molded product in contact with the. Preferably said means is a housing formed on the inner surface along the edge of the step. The present invention also relates to the stopper described above.

  The present invention will now be described by way of a detailed description of a preferred embodiment thereof with reference to the accompanying drawings, which are not limiting and are given merely by way of example. .

  Referring to FIG. 1, a towel rack radiator is provided with a tubular manifold 1 as shown. Preferably, the manifold has a flat surface formed with an array of holes for receiving both ends of the tube 3, in which the manifold and tube are created to create the site shown in the detailed illustration. There is a suitable gap that can create a bond by brazing between. The tube may be tapered at both ends so that it can be easily inserted to the correct depth. The ends may also be deformed by a suitable machine inserted into the manifold from one end after being inserted.

  According to a first aspect of the invention, the brazing material is positioned on the outer surface of the end of the tube and then inserted into the hole in the proper position. That is, the brazing material is disposed in the manifold near the joint so that once it is melted, the brazing material can be drawn into the gap space of the joint by brazing. The tube and manifold are placed in a furnace for melting the brazing material. In general, a fully assembled radiator is placed in a furnace and the brazing material is cooled and solidified, resulting in the final product. The brazing material may be positioned in various ways. For example, a coating 5 comprised of a thin sheet of brazing material (eg, a metal laminate) may be applied or deposited on the end 4 of the tube 3 as shown in FIG. According to a preferred embodiment of the invention, the brazing material is arranged in a preferred manner, for example in the form of a ring of metal wire that can be arranged around the end of the tube. More preferably, the ring 6 may be arranged on a special groove 7 (see FIG. 3) formed around the end 4 of the tube (for example by cutting the outer surface 8 of the tube). The ring may be an open ring to facilitate positioning.

  In FIG. 4, a tube 3 is shown inserted into a hole in the surface 2 of the manifold 1 and, prior to the heating step, the ring is required to be located near the joint and so on. Thus, the ring is drawn into the gap between the manifold wall 9 and the tube 3 by capillary action. The end 4 of the tube 3 protrudes into the manifold by a short length, for example 1 to 3 mm, for example 2 mm. The brazing material is required to be able to reach the inside of the hole if it is deposited prior to insertion of the tube into the manifold 1. Advantageously, since the groove 7 does not protrude from the surface 8, it is deep enough to fit the preferred shape of the metal. Alternatively, the end of the tube may be tapered to facilitate proper insertion and the groove 7 may be absent if the taper is sufficient. In such a case, the brazing material is required to have a shape that can continue to be located around the tube, which may be a ring that is firmly fixed around the surface of the tube, for example by elastic force. By doing so, there is an advantage that the portion around the tube can be expanded without being exposed. Advantageously, tapering and grooves may be combined in any suitable manner. In order to correctly insert the tube, a guide 10 may be provided on the surface 8 of the tube, for example it may be a ring-shaped ridge that prevents further insertion of the tube.

  The positioning of the brazing material can also follow the mutual positioning of the metal members to be joined.

  If the tube is fixed to the manifold, for example, the ring may be placed at the end of the tube already inserted by a special mechanical device.

  In many cases, it is possible to vary the end of the tube with the brazing material positioned from within, according to existing methods. That is, doing so is preferred because the position can be managed by the metal beyond the correct positioning of the bond.

  Positioning the brazing material in the preferred shape is carried out automatically and appropriately, especially when forming the exterior of the bond in the form of a paste, as opposed to the positioning of the brazing material.

  FIGS. 5 and 6 show a stopper 11 for closing the end 12 of the manifold 2 according to a special embodiment of the invention.

  The outer edge 13 advantageously has the outer shape of a manifold cross section. A step 14 is formed toward and above the inner surface 15 of the stopper, and the outer surface 16 may enter the interior of the manifold. That is, a gap is formed between the inner surface 17 of the manifold and the surface 16 so that the molten brazing material is drawn (FIG. 7). In a manner similar to the step 14, a housing 19 may be formed further towards the inner surface, which is suitable for receiving a molding 18 of brazing material (which may be a suitably shaped ring of metal wire). Yes. A ring used as a tube by its own elastic force and / or by special means such as a protrusion 20 formed by stamping on the inner surface 15 of the stopper near the edge of the housing 19 In the same manner, the molding of the brazing material is held in place. Such a housing serves as a means for holding the brazing material in place, with or without protrusions as in this case.

  According to a preferred embodiment, the projection for holding the molding in place extends over the entire edge 22 portion of the inner surface 15 of the stopper 11, especially when the molding is in the shape of an open ring. May be continuously stretched. For example, when the stopper has the shape shown in FIG. 5, i.e., a semi-circular or rounded portion 23 opposite the straight portion 24 defined by two (rounded) corners 25, a continuous protrusion. The portion extends across the entire portion 23 and the entire corner 25 (the straight portion 24 may or may not extend), while the central portion 26 remains free of protrusions. This facilitates the insertion of the open ring shaped part, which is particularly advantageous when it is desired to be done by a machine. In accordance with what has been illustrated above, the person skilled in the art will be able to add other protrusions to the stopper having the shape shown in FIG. You may find a possible way.

  The stopper has one or more screw holes 21 or non-through holes, depending on whether it is required to connect the tube to the relevant end of the manifold. As shown in FIG. 7, the housing 19 is defined by an internal surface 17 of the manifold, and the brazing material is less likely to scatter once welded, thus increasing process efficiency.

  In general, the copper that forms the basis of the alloy is used as a welded steel element in the construction of the radiator.

  As described above, when a molded product of brazing material is used, a wide range of configurations can be used at that time. This indicates that the molded product can be selected based on manufacturing process and quality requirements. For example, alloys that melt at low temperatures may be used in current insertions, thus reducing the furnace temperature. By doing so, the mechanical tensions of the finished product can be reduced, thus eliminating the need to correct the deformation by heating. As for the surface, it can be made to be of higher quality by further processing such as chromium plating. Also, a colored alloy suitable for the color of the part of the machine to be joined may be selected, for example if the material of the part to be joined is stainless steel, the alloy used is copper-nickel, or copper -There are alloys based on silver. If the aluminum parts are bonded, an aluminum-silicon alloy may be selected as the brazing material, so that an aluminum radiator can be constructed more easily.

  If the type of brazing material is required to be zinc or aluminum, for example based on an alloy such as aluminum-silicon, it is possible to use a molded article provided with an oxygen scavenger. For example, a metal wire shaped article having an oxygen scavenger core may be used. The metal ring may be obtained by cutting the wire from the coil and, if desired, the ring may be suitably held in a mold such as a ring for a manifold stop.

  The metal wire may be selected from any suitable diameter, for example 0.5 to 2 mm, for example 1 mm.

  The processes described so far are suitable for the construction of a towel rack type radiator in which the tubular members to be joined have a shape that is difficult to reach from the inside. For example, the manifold may have a diameter of 20 to 50 mm, and a tube with a suitably smaller diameter, for example 10 to 30 m. Also, the tube may often have a cross-section other than a circle, such as an ellipse. Even in such a case, the molded article of the brazing material has a sufficient structure. The thickness of the metal can vary, for example, between 0.5 and 2 mm.

  However, in this process, other applications different from those exemplified above can also be used without departing from the scope protected by the claims.

  By following the preferred mode of the present invention, it becomes possible to carry out the in-furnace brazing process as described above. However, heating can also be used for joining the members by other methods, for example by passing through a furnace.

The figure which shows the detail of a towel rack type radiator. FIG. 2 is a schematic view of a towel rail radiator tube inserted into a manifold to form a brazed joint. FIG. 3 is a schematic cross-sectional view of a tube of a towel radiator that is prepared for positioning and brazing a brazing material. FIG. 3 is a schematic cross-sectional view of a towel rail radiator tube prepared for positioning and brazing a brazing material, inserted into a manifold. The figure seen from the schematic inner side of the stopper for closing the manifold of a towel rack type radiator. FIG. 3 is a schematic cross-sectional side view of a stopper for closing a manifold of a towel rack radiator. FIG. 3 is a schematic cross-sectional side view of a stopper inserted into a manifold, ready to braze.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manifold 2 Surface 3 Pipe | tube 4 End part 5 Coating 6 Ring 7 Groove 8 External surface 9 Wall part 10 Guide 11 Stopper 12 End part 13 Outer edge part 14 Step part 15 Internal surface 16 External surface 17 Internal surface 18 Molding of brazing material 19 Housing 20 Protrusion 21 Screw hole 22 Edge 23 Semicircular or round part 24 Straight line part 25 Corner 26 Central part

Claims (19)

A brazing step of joining two metal members (1, 3, 11), wherein at least one of said metal members (1) is tubular,
Positioning a brazing material (5, 6, 18) on one of the metal members;
Positioning the metal members to be connected to each other;
Heating the metal member to a temperature capable of melting the brazing material;
Have
The brazing step, wherein the brazing material is positioned inside the tubular metal member prior to melting.   The process according to claim 1, wherein the heating is performed in a furnace.   The process according to claim 1, wherein the brazing material has a shape of a molded product made of metal.   The process according to claim 3, wherein the molded article is a properly held metal wire.   The end (4) of the tube (3) is brazed in a hole provided in the inner wall surface (2) of another tubular metal member (1). The process according to any one of the above.   Process according to claim 5, characterized in that a brazing coating (5) is applied or distributed around the end of the tube and the end of the tube is then inserted into the hole.   6. The process of claim 5, wherein a molded article made of metal is positioned around the end of the tube, and the end of the tube is then inserted into the hole.   The process according to claim 7, characterized in that the molded product made of metal is a ring (6) of metal wire.   9. Process according to claim 8, characterized in that the ring is positioned in a special groove (7) provided around the end of the tube.   The process according to claim 5, wherein the end of the tube is tapered.   11. Process according to any one of claims 5 to 10, characterized in that the end of the tube is changed in shape after being inserted into the hole.   The process according to any one of claims 5 to 11, wherein the end of the tube is inserted into the hole so as to protrude into the tubular member by a length of 1 to 3 mm.   5. Process according to claims 1-4, characterized in that the stopper (11) is brazed against the end (12) of the tubular manifold (1).   Said stopper has an internal surface (15) provided with means (19, 20) for holding a brazing material in the form of a molded part (18) in contact with the joint to be brazed. The process according to claim 13.   The stopper has a step (14) suitable for being inserted into the tubular manifold, the side surface (16) of the step being the side surface (17) of the manifold. 15. The process according to claim 14, characterized in that it creates a joint to be brazed.   Said means for holding the brazing material in the form of a molded part (18) in contact with the joint to be brazed is a housing (19) formed along the outer edge (13) of the stopper. The process according to claim 14 or 15, characterized in that:   17. Process according to claim 16, characterized in that the means for holding a brazing material in the form of a molded article comprises a series of protrusions (20) provided on the inner surface 15 of the stopper.   The process according to any one of claims 1 to 17, wherein the metal members to be joined are part of a towel rack radiator. A stopper (11) for closing the end of the tubular manifold (1),
An inner surface (15) provided with means (19, 20) for holding a brazing material in the form of a molded product in contact with the surface (16) forming the joint to be brazed with the manifold; A stopper characterized by having.

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