JP2005211931A - Compound material for brazing, method for manufacturing the same, and brazed product using compound material for brazing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an improvement in press forming and working properties of a compound material for brazing by preventing the rapture of a brazing layer and the fracture of a base material. <P>SOLUTION: The compound material 1 for brazing is provided with the brazing layer 6 formed of two or more kinds or two or more layers of metallic layers on the surface of the base material 2, wherein cracks are preliminarily formed at fine intervals on the brazing layer 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brazing composite material in which a brazing layer is provided on the surface of a base material, and more particularly to a brazing composite material capable of improving a brazing function and improving heat resistance and corrosion resistance, and a method for producing the same. The present invention relates to a brazing product using a brazing composite material.

  Conventionally, stainless steel clad brazing filler metal has been used as a joining material for automobile oil coolers. The stainless steel-based clad brazing material is configured by clad copper having a function as a brazing material on one surface or both surfaces of a stainless steel plate.

  Further, as a brazing material for parts such as stainless steel, nickel base and cobalt base alloy, various nickel brazing excellent in oxidation resistance and corrosion resistance of the joint are defined by JIS standards.

  Further, the nickel brazing material for connecting the heat exchanger is a nickel brazing material constituted by adding 4 wt% to 22 wt% of a metal powder selected from Ni, Cr, and Ni—Cr alloy to powdered nickel brazing. Yes (see Patent Document 1).

  On the other hand, as a method for producing a brazing composite, a first base layer selected from the group consisting of stainless steel and a nickel superalloy is formed, and a group consisting of nickel or high nickel alloy and titanium or high titanium alloy is formed. After forming a second layer composed of a multi-component material selected from the above, there is a method of rolling and integrating the first base layer and the second layer with a pair of forming rolls (Patent Document 2). reference). FIG. 4 shows a structural example of the brazing composite material 51 manufactured by the above method. As shown in the figure, the brazing composite 51 is composed of nickel (or nickel alloy) 53 and titanium (or high titanium alloy) 54 on one surface of stainless steel 52 serving as the first base layer. A brazing layer 55 to be a layer is provided.

  In addition, as shown in FIG. 5, there was also a brazing composite material 56 in which a brazing layer 57 composed of three layers of nickel 53, titanium 54, and nickel 53 was provided on one surface of stainless steel 52.

JP 2000-107883 A Japanese Patent Laid-Open No. 7-299592

  However, the brazing composite material 51 (56) manufactured by the manufacturing method of Patent Document 2 described above has the following problems.

  When the brazing composite material 51 (56) is subjected to plastic working such as press working, it is preferable that the mechanical properties of the material are soft and have a large elongation. In order to obtain this characteristic, the brazing composite material 51 (56) must be annealed. Moreover, in order to ensure even higher workability, heating at a higher temperature and longer time is required.

  However, in the brazing composite material 51 (56), since the brazing layer 55 (57) is composed of a plurality of metal layers 53 and 54, when heated at a high temperature for a long time, diffusion between the metal layers will occur. The reaction proceeds. The reaction layer produced by the diffusion reaction between nickel / titanium is more fragile than the nickel / titanium single layer state. For this reason, the material is cured and the elongation amount becomes small, so that the workability is lowered.

  Because of the above constraints, the stainless steel 52 is not completely softened even if the heating conditions are optimized within the constraints. When press molding is performed in such a state, the entire material is pulled, and there is a problem that the brazing composite material 51 (56) is likely to break as compared with a stainless steel that has been completely annealed. FIG. 6 shows a state in which the brazing layer 55 of the brazing composite material 51 (56) is torn. As shown, the brazing layer 55 clad to the stainless steel 52 is torn.

  The cause of this is considered that the elongation of the stainless steel 52 is not uniform because the elongation of the clad brazing layer 55 is greatly inferior to that of the stainless steel 52 as the base material. That is, in a section where cracks (occurred every several tens to several hundreds of μm) are generated in the brazing layer 55 during press forming, the portion of the stainless steel 52 extends as it is, but a portion where no crack is generated in the brazing layer 55 ( The elongation of the stainless steel 52 (particularly in the vicinity of the brazing layer 55) of the brazing layer 55 is limited / suppressed by the elongation of the clad brazing layer 55.

  In short, since the interval between the cracked portions of the brazing layer 55 is wide, there are many portions where the amount of elongation of the stainless steel 52 is limited / suppressed, and there are few portions where the stainless steel 52 is stretched as it is. The elongation amount required for press forming is not obtained, the cracked brazing layer 55 is largely separated, and the brazing layer 55 in that portion is broken or the base material (stainless steel 52) is broken. It is thought that it leads to breakage.

  Accordingly, the present invention has been made to solve the above-mentioned problems. The purpose of the present invention is to break the brazing layer even if a brazing layer formed of two or more metal layers is provided on the surface of the base material. Another object of the present invention is to provide a brazing composite material having a high press-forming processability and a method for producing the same, and a brazed product using the brazing composite material.

  In order to achieve the above object, the invention according to claim 1 is directed to a brazing composite material in which a brazing layer formed of two or more metal layers on the surface of a base material is provided. This is a brazing composite material in which cracks are formed in advance at fine intervals.

  The invention according to claim 2 is a composite material for brazing processing in which each metal layer of the brazing layer is selected from copper or a copper alloy, titanium or a titanium alloy, and nickel or a nickel alloy.

  The invention according to claim 3 is the brazing composite material in which the cracks are formed at intervals of 150 μm or less.

  The invention according to claim 4 is a brazing composite material in which the substrate is made of stainless steel.

  The invention according to claim 5 is a method for producing a brazing composite material in which a base material and a brazing layer formed of two or more metal layers are rolled with a pair of forming rolls. This is a method for producing a brazing composite material in which a forming roll provided with a protrusion is pressed against the brazing layer and cracks are formed in the brazing layer at fine intervals.

  The invention according to claim 6 is a brazed product formed by thermally welding the brazing composite material manufactured by the manufacturing method according to any one of claims 1 to 4 or claim 5.

  According to the present invention, it is possible to prevent the breakage of the brazing layer and the breakage of the base material, and to achieve excellent effects such as the improvement of the press molding processability of the brazing composite material.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic sectional view showing a preferred embodiment of a composite material for brazing according to the present invention, and FIG. 2 is a side view showing a forming roll used in the method for producing a composite material for brazing according to the present invention. It is a figure and the principal part enlarged view. In addition, the principal part enlarged view of the forming roll surface is shown in a broken-line circle in FIG.

  As shown in FIG. 1, the brazing composite material 1 according to the present embodiment includes a nickel (or nickel alloy) layer 4, a titanium (or titanium alloy) layer 5, A nickel (or nickel alloy) layer 4 is clad and formed in that order. The nickel layer 4, the titanium layer 5, and the nickel layer 4 constitute a brazing layer 6.

  The metal layer constituting the brazing layer 6 is not limited to the nickel (or nickel alloy) layer 4 or the titanium (or titanium alloy) layer 5 but can be arbitrarily selected from a metal group including a copper or copper alloy layer. is there.

  A plurality of cracks 7 are formed in the brazing layer 6 at fine intervals. The crack 7 is formed over the entire thickness direction of the brazing layer 6 and has a depth that reaches from the surface of the brazing layer 6 to the surface of the substrate 2. The cracks 7 are formed in a straight line shape in plan view, and the adjacent cracks 7 are formed in parallel with each other at an interval of 150 μm or less. The crack 7 is formed along the width direction of the brazing composite material 1. Note that the cracks 7 may be formed not only in the width direction of the brazing composite material 1 but also in the longitudinal direction so as to have a lattice shape as a whole.

  Next, a method for manufacturing the brazing composite material 1 having the above configuration will be described.

  First, a nickel plate, a titanium plate, and a nickel plate are overlapped to form a three-layer structure, hot rolled, and then cold rolled to form a clad plate. The clad plate is clad on stainless steel by a rolling method, and then cold-rolled to form the composite 12.

  Then, as shown in FIG. 2, the composite 12 is rolled between a pair of forming rolls 8 and 9.

  A plurality of protrusions 11 are provided on the surface of the molding roll 8 that contacts the brazing layer 6 of the pair of molding rolls 8 and 9. As shown in the enlarged portion of FIG. 2, the projection height h of the projection 11 is formed to be slightly shorter than the thickness of the brazing layer 6, for example, 35 to 45 μm so as to give the crack 7 only to the brazing layer 6. ing. In other words, the protrusion height h is a height necessary and sufficient to give the crack 7 to the layer to which the crack 7 of the brazing layer 6 is to be provided. For example, if the structure is a Ni / Ti / Ni structure, the brittle Ti It can be high enough to reach the cracks in the layer. On the other hand, the protrusion interval d between the protrusions 11 is formed to be 150 μm or less.

  The forming roll 8 is brought into contact with the brazing layer 6 and the forming roll 9 is brought into contact with the substrate 2 to perform rolling. As a result, the brazing layer 6 is pressed against the forming roll 8, and a crack 7 is formed as shown in FIG.

  At this time, since the height 11 of the protrusion 11 is slightly shorter than the thickness of the brazing layer 6, the crack 7 is formed only in the brazing layer 6, and a crack is formed in the substrate 2. It will never be done. As a result, the base material 2 can be prevented from being easily broken, and the base material 2 can be efficiently stretched.

  Moreover, the plate | board thickness of the composite material 1 for brazing process other than the generation | occurrence | production part of the crack 7 is processed so that it may become 95% or more before a crack provision process. That is, the processing degree of the crack imparting process is 5% or less.

  Then, a final annealing treatment is performed on the brazing composite material 1 in which the crack 7 is finally formed.

  According to the brazing composite material 1 manufactured by the above method, since the fine crack 7 is formed in the brazing layer 6 in advance, when a tensile load is applied to the brazing composite material 1 by press molding or the like. The base material 2 (stainless steel) extends as it is at the portion where the crack 7 occurs. Since a large number of cracks 7 are formed at a short distance pitch, a large portion of the stainless steel itself having a large elongation can be obtained, and a large amount of elongation of the entire brazing composite 1 can be secured. Therefore, the amount of elongation necessary for the brazing composite material 1 can be obtained.

  Further, when the base material 2 (stainless steel) is stretched at the portion where the crack 7 is generated, the width of the crack 7 is increased. However, since a large number of cracks 7 are formed in advance, the amount of elongation necessary for press forming is dispersed. The elongation amount of the base material 2 (stainless steel) for each crack 7 occurrence portion becomes small. Therefore, the crack 7 does not expand too much, and the brazing layer 6 does not break.

  Furthermore, since the arrangement | positioning space | interval of the crack 7 is 150 micrometers or less, the elongation suppression amount of the base material 2 by the brazing layer 6 can be suppressed, and the elongation amount of the composite material 1 for brazing can be increased.

  As described above, according to the composite material 1 for brazing according to the present embodiment, the brazing layer 6 and the base material 2 can be prevented from being broken, and the press workability of the brazing composite 1 is improved. Can be achieved.

  Moreover, since the workability of the crack imparting process is 5% or less, it is possible to prevent the mechanical properties from being lowered due to work hardening, and the workability when the brazing composite material 1 is processed into an arbitrary shape is deteriorated. There is nothing.

  In addition, the manufacturing method of the composite material 1 for brazing is not restricted to the said method, The other method may be sufficient as long as the crack 7 can be provided to the brazing layer 6. FIG.

  Therefore, brazing such as an oil cooler for an automobile, an oil cooler for a hydraulic unit, an exhaust gas recirculation (EGR) cooler, a cooler for a fuel cell reformer, etc., formed by thermally welding the brazing composite material 1 having the above structure. Since the brazing product has high press molding processability of the brazing composite material 1, the brazing layer 6 and the base material 2 are not broken. In addition, it can be easily processed into a complicated shape.

  In the above-described method for producing a composite material for brazing, four types of composite materials for brazing (Examples 1 and 2 and Comparative Examples 1 and 2) were formed under the following conditions. 2 and Comparative Examples 1 and 2 and a conventional brazing composite material (Conventional Example 1) were subjected to press molding, and the quality of the workability was comparatively evaluated.

(Example 1)
A coiled nickel plate with a plate thickness of 1.0 mm, a pure titanium plate with a plate thickness of 2.0 mm, and a coiled nickel plate with a plate thickness of 1.0 mm are superposed to form a total of three layers and hot rolled to obtain a plate. A clad plate having a thickness of 1.4 mm was formed, and subsequently finished into a clad plate having a thickness of 0.25 mm by cold rolling.

  This clad plate was clad onto SUS304 (thickness 2.5 mm) by a rolling method and cold-rolled to produce a composite having a thickness of 0.5 mm. At this time, the thickness of the brazing layer is 50 μm.

  About the said composite_body | complex, the final rolling process was performed with the shaping | molding roll provided with the projection part (projection part height 40 micrometers, projection part space | interval 100 micrometers). The degree of processing at this time was 5% or less.

  This composite was subjected to a finish annealing treatment at 900 ° C. for 4 minutes in a reducing atmosphere.

(Example 2)
A coiled nickel plate with a plate thickness of 1.0 mm, a pure titanium plate with a plate thickness of 2.0 mm, and a coiled nickel plate with a plate thickness of 1.0 mm are superposed to form a total of three layers and hot rolled to obtain a plate. A clad plate having a thickness of 1.4 mm was formed, and subsequently finished into a clad plate having a thickness of 0.25 mm by cold rolling.

  This clad plate was clad onto SUS304 (thickness 2.5 mm) by a rolling method and cold-rolled to produce a composite having a thickness of 0.5 mm. At this time, the thickness of the brazing layer is 50 μm.

  About the said composite_body | complex, the final rolling process was performed with the forming roll which provided the projection part (projection part height 45 micrometers, protrusion part space | interval 120 micrometers). The degree of processing at this time was 5% or less.

  This composite was subjected to a finish annealing treatment at 900 ° C. for 4 minutes in a reducing atmosphere.

(Comparative Example 1)
A coiled nickel plate with a plate thickness of 1.0 mm, a pure titanium plate with a plate thickness of 2.0 mm, and a coiled nickel plate with a plate thickness of 1.0 mm are superposed to form a total of three layers and hot rolled to obtain a plate. A clad plate having a thickness of 1.4 mm was formed, and subsequently finished into a clad plate having a thickness of 0.25 mm by cold rolling.

  This clad plate was clad onto SUS304 (thickness 2.5 mm) by a rolling method and cold-rolled to produce a composite having a thickness of 0.5 mm. At this time, the thickness of the brazing layer is 50 μm.

  About the said composite_body | complex, the final rolling process was performed with the forming roll which provided the projection part (projection part height 40 micrometers, protrusion part space | interval 220 micrometers). The degree of processing at this time was 5% or less.

  This composite was subjected to a finish annealing treatment at 900 ° C. for 4 minutes in a reducing atmosphere.

(Comparative Example 2)
A coiled nickel plate with a plate thickness of 1.0 mm, a pure titanium plate with a plate thickness of 2.0 mm, and a coiled nickel plate with a plate thickness of 1.0 mm are superposed to form a total of three layers and hot rolled to obtain a plate. A clad plate having a thickness of 1.4 mm was formed, and subsequently finished into a clad plate having a thickness of 0.25 mm by cold rolling.

  This clad plate was clad onto SUS304 (thickness 2.5 mm) by a rolling method and cold-rolled to produce a composite having a thickness of 0.5 mm. At this time, the thickness of the brazing layer is 50 μm.

  About the said composite_body | complex, the final rolling process was performed with the shaping | molding roll provided with the projection part (projection part height 70 micrometers, protrusion part space | interval 80 micrometers). The degree of processing at this time was 5% or less.

  This composite was subjected to a finish annealing treatment at 900 ° C. for 4 minutes in a reducing atmosphere.

(Conventional example 1)
A coiled nickel plate with a plate thickness of 1.0 mm, a pure titanium plate with a plate thickness of 2.0 mm, and a coiled nickel plate with a plate thickness of 1.0 mm are superposed to form a total of three layers and hot rolled to obtain a plate. A clad plate having a thickness of 1.4 mm was formed, and subsequently finished into a clad plate having a thickness of 0.25 mm by cold rolling.

  This clad plate was clad onto SUS304 (thickness 2.5 mm) by a rolling method and cold-rolled to produce a composite having a thickness of 0.5 mm.

  This composite was subjected to a finish annealing treatment at 900 ° C. for 4 minutes in a reducing atmosphere.

  The alloy materials formed by the above-described examples, comparative examples, and conventional examples were cut into a size of 100 mm × 100 mm and subjected to press forming so as to have a cross-sectional shape as shown in FIG. . The bending radius of each bending part is 1 mm.

  Table 1 below shows the workability of each example, comparative example, and conventional example. As shown in Table 1, the samples formed in Examples 1 and 2 of the present invention could be processed without breakage, but the samples formed in Comparative Examples 1 and 2 and Conventional Example 1 resulted in breakage. In Comparative Example 1 and Conventional Example 1, it is considered that the suppression of the elongation of the base material by the brazing layer clad on the base material is the cause of the break, and in Comparative Example 2, it is considered that the crack is imparted to the base material. .

  From the above results, the crack interval is preferably 150 μm or less.

It is the cross-sectional schematic diagram which showed suitable embodiment of the composite material for brazing process which concerns on this invention. It is the side view and principal part enlarged view which showed the forming roll used for the manufacturing method of the composite material for brazing process which concerns on this invention. It is the side view which showed the press molding process shape in an Example. It is the cross-sectional schematic diagram which showed the composite material for the conventional brazing process. It is the cross-sectional schematic diagram which showed the composite material for the conventional brazing process. It is the cross-sectional photograph which showed the tearing state of the conventional brazing composite material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite material for brazing process 2 Base material 4 Nickel layer 5 Titanium layer 6 Brazing layer 7 Crack 8 Forming roll 11 Protrusion part

Claims (6)

  A brazing composite material in which a brazing layer formed of two or more metal layers and two or more metal layers is provided on a substrate surface, wherein the brazing layer is preliminarily formed with cracks at fine intervals. Composite material for processing.   The composite material for brazing according to claim 1, wherein each metal layer of the brazing layer is selected from copper or a copper alloy, titanium or a titanium alloy, and nickel or a nickel alloy.   The composite material for brazing according to claim 1, wherein the cracks are formed at intervals of 150 μm or less.   The composite material for brazing according to any one of claims 1 to 3, wherein the base material is made of stainless steel.   In a method for producing a composite material for brazing, in which a base material and a brazing layer formed of two or more kinds and two or more metal layers are rolled with a pair of molding rolls, molding having a plurality of protrusions on the surface A method for producing a composite material for brazing, wherein a roll is pressed against the brazing layer to form cracks in the brazing layer at fine intervals. A brazed product formed by heat-welding the brazing composite material produced by the production method according to any one of claims 1 to 4 or 5.