A method of brazing

Abstract

The present application relates to a kind of brazing coating methods, including diamond is uniformly laid on the surface of brazing coating alloy, diamond and brazing coating alloy are compacted using pressure component operation;The diamond surface of the brazing coating surface to be covered of the workpiece to be brazed is covered;Turn over workpiece, heating is carried out on the brazing coating alloy surface away from diamond surface, so that the brazing coating alloy melts, sinks;The surface of the workpiece to be brazed away from diamond on the surface of the workpiece to be brazed is heated, and the brazing coating process is completed.The present application solves the technical problem of the environment in the prior art in brazing coating process, further solves the problem that diamond is easy to graphitize under high temperature, further solves the problem that the bonding force between diamond and brazing coating alloy is poor, realizes the technical effects such as environment-friendly, brazing coating alloy wide applicability and excellent performance of workpiece after brazing coating.

Description

Technical Field

[0001] This invention relates to the field of brazing, and more particularly to a brazing method. Background Technology

[0002] Diamond is a commonly used wear-resistant particle in coating materials. It can be used not only in a wide range of agricultural machinery fields such as furrow openers, subsoilers, plowshares, rotary tillers and other agricultural machinery tools, but also plays an important role in the automotive, aerospace, medical, machinery manufacturing and electronics fields.

[0003] Traditional diamond brazing processes involve either applying a brazing paste to the workpiece surface or first applying a brazing alloy to the workpiece surface and then placing the diamond. The former primarily involves mixing the brazing alloy and diamond to prepare a paste, requiring a binder, which is typically an organic binder. This not only pollutes the environment but also reduces the density of the brazing coating. The latter method, however, suffers from the drawback of diamond's tendency to graphitize at high temperatures (above 800°C), affecting its overall rigidity and limiting the use of many high-temperature alloys. Furthermore, because diamond is difficult to wet with metals, the latter method results in poorer adhesion between the diamond and the brazing alloy during the brazing process, further restricting the types of alloys that can be used.

[0004] The aforementioned existing technologies all limit the development of diamond brazing technology. Summary of the Invention

[0005] This invention proposes a brazing method that addresses the environmentally unfriendly technical problems in the existing brazing process, further solves the problem of diamond easily graphitizing at high temperatures, and further solves the problem of poor bonding between diamond and the brazing alloy. It achieves technical effects such as environmental friendliness, wide applicability of the brazing alloy, and excellent performance of the workpiece after brazing.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A solder coating method, characterized by comprising the following steps:

[0008] 1) Spread diamond evenly on the surface of the brazing alloy;

[0009] 2) A pressure component is used to compact the diamond and the brazing alloy, so that the diamond is embedded into the brazing alloy to a certain depth, thereby obtaining a composite brazing alloy containing diamond;

[0010] 3) Cover the diamond surface of the composite brazing filler metal onto the surface of the workpiece to be brazed;

[0011] 4) Simultaneously flip the brazing workpiece and the composite brazing filler metal so that the composite brazing filler metal and the workpiece to be brazed are in an up-down position and the diamond is located between the brazing alloy and the workpiece to be brazed;

[0012] 5) Heat the brazing alloy surface of the composite brazing filler metal away from the diamond surface to melt and sink the brazing alloy; then stop heating.

[0013] 6) Heat the surface of the workpiece to be brazed away from the diamond face to complete the brazing process.

[0014] Furthermore, in step 1), a certain amount of diamond is placed on the surface of the brazing alloy, and the diamond is evenly spread on the surface of the brazing alloy using a brush.

[0015] Furthermore, in step 2), the compaction operation is to use a pressure head as a pressure component to compress the diamond, or to use a clamp as a pressure component to compress the diamond and the brazing alloy together, or to use a roller as a pressure component to compress the diamond or the diamond and the brazing alloy together.

[0016] This invention does not limit the above-mentioned compaction operations, nor does it restrict the shape and size of the pressure head, clamp, roller, etc., which can be determined according to actual needs. When using a pressure head, it can be a hydraulic press pressure head, but is not limited to this. When using a clamp, the diamond and brazing alloy are placed between the two sides of the clamp for compression. When using rollers, a single roller can be used to compress the diamond, or two rollers can be used to cooperate to place the diamond and brazing alloy together between the two rollers for compression.

[0017] Furthermore, in step 2), the certain depth is when the diamond is completely embedded in the brazing alloy without being exposed.

[0018] This makes it difficult for diamonds to fall off the surface of the brazing alloy.

[0019] Furthermore, in step 1), the thickness of the brazing alloy is 1.5-2.5 times the thickness of the diamond layup.

[0020] This makes it difficult for diamond to penetrate the brazing alloy during the compaction process. At the same time, if the thickness is too low, the diamond may quickly expose the brazing alloy during heating, making it difficult to control the molding. If the thickness is too high, the overall coating may be too thick, making it difficult for the diamond to perform its wear-resistant function. In addition, excess brazing alloy is wasted, and more brazing energy is consumed.

[0021] Furthermore, in step 5), heating is stopped when the brazing alloy surface away from the workpiece to be brazed forms an uneven surface and the diamond is not exposed.

[0022] Therefore, to prevent diamond from coming into direct contact with heat sources and causing localized high temperatures, which would otherwise lead to diamond graphitization.

[0023] Furthermore, in step 6), heating is stopped when the diamond just emerges from the brazing alloy surface away from the workpiece to be brazed.

[0024] Based on this, the diamond does not come into direct contact with the heat source. Instead, the heat from the workpiece to be brazed is transferred to the brazing alloy, thereby forming a dense alloy layer. At the same time, the brazing alloy can also encapsulate the diamond, preventing it from falling off, and the diamond can also play its wear-resistant role.

[0025] Furthermore, the density of the diamond is less than the density of the brazing alloy.

[0026] Based on this, the density of general brazing alloys is greater than that of diamond. In the brazing process of this invention, the brazing alloy melts and sinks, while the diamond slowly floats to the surface. This process can protect the diamond from direct contact with the heat source, which would cause local graphitization, and the brazing alloy can better encapsulate the diamond to prevent it from falling off, thereby increasing the performance of the brazed workpiece and making the brazing alloy more widely applicable.

[0027] Furthermore, the brazing alloy is an iron-based, nickel-based, or copper-based alloy.

[0028] Furthermore, the diamond has a particle size of 50-300 mesh.

[0029] Compared with the prior art, the technical solution of this invention has the following advantages:

[0030] 1. This invention uses mechanical pressing to pre-assemble diamond and brazing alloy, eliminating the need for adhesives or even organic adhesives, which is environmentally friendly;

[0031] 2. In this invention, after the diamond and the brazing alloy are assembled, the diamond surface is placed facing the workpiece to be brazed. The brazing alloy surface, which is farther from the diamond, is heated first, followed by heating the workpiece surface, which is also farther from the diamond. This causes the brazing alloy, which has a higher density than the diamond, to melt and sink, while the diamond slowly floats upwards. This protects the diamond from direct heat source contact that could cause localized graphitization, and also allows the brazing alloy to better encapsulate the diamond, preventing it from falling off. This improves the performance of the brazed workpiece. It eliminates the need to modify the brazing alloy and / or the diamond to increase the wettability of the diamond and the brazing alloy or to address the graphitization of the diamond at high temperatures. This allows for the use of conventional brazing alloys with higher melting points, increasing the availability of brazing alloys and reducing the cost of modifying the brazing alloy and / or the diamond.

[0032] 3. By constructing an overall brazing process, this invention overcomes the technical problems of existing technologies, such as environmental unfriendliness, easy diamond detachment, and poor applicability of brazing alloys, and provides a new approach to brazing processes, which has broad practical significance. Detailed Implementation

[0033] The principles and features of the present invention are described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, specific conditions or manufacturer-recommended conditions should be followed in the embodiments. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0034] Material:

[0035] The brazing alloy is a Ni-Cr alloy, wherein the mass fraction is 82% Ni, 8% Cr, 4% Fe, 3% Si, and 3% B; the Ni-Cr alloy is a 300μm thick alloy sheet;

[0036] The diamond has a particle size of 100 mesh;

[0037] The workpiece to be brazed is Q235 steel.

[0038] Example 1:

[0039] 1) Place the Ni-Cr alloy horizontally and spread diamonds evenly on the surface of the Ni-Cr alloy so that the diamonds do not overlap. At this time, the thickness of the diamond layer is about 1 / 2 of the thickness of the Ni-Cr alloy.

[0040] 2) Align the hydraulic press head with the diamond and press the diamond into the Ni-Cr alloy so that the diamond is completely embedded in the Ni-Cr alloy to obtain a composite brazing filler metal containing diamond.

[0041] 3) Cover the diamond surface of the composite brazing filler metal with Q235 steel;

[0042] 4) Simultaneously flip the Q235 steel and the composite brazing filler metal so that the composite brazing filler metal and the Q235 steel are in an up-down position and the diamond is located between the Ni-Cr alloy and the Q235 steel;

[0043] 5) Under argon protection, induction heating is performed on the Ni-Cr alloy surface of the composite brazing filler metal away from the diamond surface at a temperature of 1050℃, so that the Ni-Cr alloy melts and sinks. After about 4 minutes, an uneven surface appears on the Ni-Cr alloy surface away from the Q235 steel and the diamond is not exposed. At this point, heating is stopped.

[0044] 6) Induction heating is performed on the surface of Q235 steel away from the diamond surface at 1050°C under argon protection for about 3 minutes. At this point, the diamond begins to be exposed on the Ni-Cr alloy surface away from the Q235 steel. Heating is then stopped, and the surface is cooled to complete the brazing process and obtain the brazed workpiece of Example 1.

[0045] Comparative Example 1:

[0046] 1) Place Q235 steel horizontally, place Ni-Cr alloy on the Q235 steel, and evenly spread diamond on the surface of Ni-Cr alloy so that the diamonds do not overlap. At this time, the thickness of the diamond layer is about 1 / 2 of the thickness of Ni-Cr alloy.

[0047] 2) Under argon protection, the diamond surface and the Q235 steel surface away from the diamond are simultaneously induction heated to a temperature of 1050℃. After 5 minutes, heating is stopped and the surface is cooled to complete the brazing process and obtain the brazed workpiece of Comparative Example 1.

[0048] test:

[0049] Wear tests were conducted on the brazed workpieces in Example 1 and Comparative Example 1 using an MML-1G abrasive wear tester. The test method followed the specifications of JB / T 7705—1995. The test load was 30 N, the rubber wheel speed was 200 r / min, the abrasive used was corundum sand with an average particle size of 60 mesh, and the wear time was 30 min. The weight loss of the samples was calculated by mass loss, and the results are shown in Table 1. Here, the diamond stripping rate was obtained by observing the ratio of the number of diamonds stripped after the wear test to the number of diamonds before the test under a microscope. The diamond weight loss was obtained by weighing the difference in the overall sample weight before and after the wear test.

[0050] Table 1

[0051] Example 1 Comparative Example 1 Weight loss / g 0.0381 0.1030 Diamond stripping rate / % 4.50 11.21

[0052] As shown in Table 1, compared to the method in Comparative Example 1, the method in Example 1 increases the encapsulation between the brazing alloy and the diamond, thus enhancing the bonding strength between them. This reduces the diamond peeling rate and improves the wear resistance of the diamond brazing alloy coating. Furthermore, it is speculated that the brazing method in Example 1 results in more contact interfaces between the diamond and the brazing alloy, leading to the formation of relatively more chromium carbides, further strengthening the bonding strength between the brazing alloy and the diamond.

[0053] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0054] 1. This invention uses mechanical pressing to pre-assemble diamond and brazing alloy, eliminating the need for adhesives or even organic adhesives, which is environmentally friendly;

[0055] 2. In this invention, after the diamond and the brazing alloy are assembled, the diamond surface is placed facing the workpiece to be brazed. The brazing alloy surface, which is farther from the diamond, is heated first, followed by heating the workpiece surface, which is also farther from the diamond. This causes the brazing alloy, which has a higher density than the diamond, to melt and sink, while the diamond slowly floats upwards. This protects the diamond from direct heat source contact that could cause localized graphitization, and also allows the brazing alloy to better encapsulate the diamond, preventing it from falling off. This improves the performance of the brazed workpiece. It eliminates the need to modify the brazing alloy and / or the diamond to increase the wettability of the diamond and the brazing alloy or to address the graphitization of the diamond at high temperatures. This allows for the use of conventional brazing alloys with higher melting points, increasing the availability of brazing alloys and reducing the cost of modifying the brazing alloy and / or the diamond.

[0056] 3. By constructing an overall brazing process, this invention overcomes the technical problems of existing technologies, such as environmental unfriendliness, easy diamond detachment, and poor applicability of brazing alloys, and provides a new approach to brazing processes, which has broad practical significance.

[0057] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A solder coating method, characterized in that, Includes the following steps: 1) Spread diamond evenly on the surface of the brazed alloy; 2) A pressure component is used to compact the diamond and the brazing alloy, so that the diamond is embedded into the brazing alloy to a certain depth, thereby obtaining a composite brazing alloy containing diamond; 3) Cover the diamond surface of the composite brazing filler metal onto the surface of the workpiece to be brazed; 4) Simultaneously flip the brazing workpiece and the composite brazing filler metal so that the composite brazing filler metal and the workpiece to be brazed are in an up-down position and the diamond is located between the brazing alloy and the workpiece to be brazed; 5) Heat the brazing alloy surface of the composite brazing filler metal away from the diamond surface to melt and sink the brazing alloy; then stop heating. 6) Heat the surface of the workpiece to be brazed away from the diamond face to complete the brazing process; In step 1), the thickness of the brazing alloy is 1.5-2.5 times the thickness of the diamond layup; In step 5), heating is stopped when the brazing alloy surface away from the workpiece to be brazed forms an uneven surface and the diamond is not exposed; In step 6), heating is stopped when the diamond just emerges from the brazing alloy surface away from the workpiece to be brazed; The density of the diamond is less than the density of the brazing alloy.

2. The brazing method according to claim 1, characterized in that, In step 1), a certain amount of diamond is placed on the surface of the brazing alloy, and the diamond is evenly spread on the surface of the brazing alloy using a brush.

3. The brazing method according to claim 1, characterized in that, In step 2), the compaction operation is to use a pressure head as a pressure component to compress the diamond, or to use a clamp as a pressure component to compress the diamond and the brazing alloy together, or to use a roller as a pressure component to compress the diamond or the diamond and the brazing alloy together.

4. The brazing method according to claim 1, characterized in that, In step 2), the certain depth is when the diamond is completely embedded in the brazing alloy without being exposed.

5. The brazing method according to claim 1, characterized in that, The brazing alloy is an iron-based, nickel-based, or copper-based alloy.

6. The brazing method according to claim 1, characterized in that, The diamond has a particle size of 50-300 mesh.