Novel alloy insert brazing process for prolonging service life of agricultural machinery cutter

Abstract

The invention discloses a novel alloy insert brazing process for prolonging the service life of an agricultural machinery cutter, and relates to the technical field of agricultural machinery. The technology comprises the steps that an agricultural machine tool base body is subjected to grooving pretreatment; preparing a high-hardness alloy insert; the insert and the brazing filler metal are assembled into the base body groove; high-temperature brazing is carried out under the vacuum or protective atmosphere, and metallurgical bonding of the alloy insert and the base body is achieved; and finally, post-welding treatment and cutting edge accurate grinding are conducted. The high-wear-resistance alloy insert is brazed at the key position of the cutting edge of the cutter, so that the local wear resistance and the overall impact resistance of the cutter are greatly improved, the problems that a traditional cutter is fast in wear and prone to breakage are solved, the service life of the agricultural machine cutter can be prolonged by multiple times, and the cutter has the advantages of being high in bonding strength, good in reliability and remarkable in economical efficiency.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery technology, specifically to a novel alloy insert brazing process for improving the service life of agricultural machinery cutting tools. Background Technology

[0002] Agricultural machinery blades, such as rotary tillers, plowshares, and harvester blades, directly rub and impact with soil, crop roots, and gravel during operation, causing extremely rapid wear on the blade edges. Frequent blade replacement not only increases agricultural production costs but also affects operational efficiency. Currently, common methods to improve blade wear resistance include integral quenching, surface hardening with cemented carbide, or spraying wear-resistant coatings. However, integral quenching may lead to decreased blade toughness and brittle fracture; while hardening or spraying processes have problems such as low bonding strength, easy peeling of the wear-resistant layer, and complex processes.

[0003] Therefore, there is an urgent need for a strengthening technology for agricultural machinery cutting tools that has high bonding strength, excellent wear resistance, and reliable processing. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a new alloy insert brazing process to improve the service life of agricultural machinery cutting tools. By designing a specific alloy insert structure and optimizing the brazing process, the high-hardness alloy insert is metallurgically bonded to the agricultural machinery cutting tool substrate, thereby forming a long-lasting wear-resistant zone in the key parts of the cutting edge and significantly extending the overall service life of the tool.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a novel alloy insert brazing process for improving the service life of agricultural machinery cutting tools, comprising the following steps:

[0006] (1) Matrix pretreatment

[0007] We provide agricultural machinery blade bases and machine precise inlay grooves in the areas where reinforcement is needed. We also perform rigorous cleaning, degreasing, and rust removal on the inlay grooves and surrounding areas to ensure a clean welding surface.

[0008] (2) Alloy insert preparation

[0009] Prepare an alloy insert that matches the shape of the inlay groove. The alloy insert is made of high-hardness and high-wear-resistant materials such as cemented carbide or high-chromium cast iron. Its shape is designed as a pointed wedge or a multi-faceted pyramid to optimize the stress and ensure that the brazing filler metal can be fully filled.

[0010] (3) Assembly and Fixing

[0011] The prepared alloy insert is precisely placed into the insert groove of the substrate and fixed using a high-temperature resistant fixture or positioning tool to ensure that there is a uniform and small gap between the insert and the groove wall; brazing filler metal is placed around the assembly.

[0012] (4) Vacuum or protective atmosphere brazing

[0013] The assembled workpiece is placed in a vacuum brazing furnace or a brazing furnace with a protective gas supply. It is heated to above the melting temperature of the brazing filler metal at a controllable heating rate and held at that temperature. This allows the liquid brazing filler metal to fully fill the gap between the alloy insert and the substrate under capillary action, achieving a metallurgical bond between the two.

[0014] (5) Post-weld treatment

[0015] After brazing is completed, the cooling rate is controlled for slow cooling to release welding stress. After the workpiece cools to room temperature, it is removed and cleaned as necessary. The part of the alloy insert that protrudes from the substrate is finely ground to form a sharp, smooth and firmly bonded reinforced cutting edge.

[0016] Preferably, the solder is a solder sheet or solder paste, and is a copper-based, silver-based, or nickel-based high-temperature solder.

[0017] Preferably, the protective gas is argon.

[0018] The present invention has the following beneficial effects:

[0019] 1. The brazing process achieves an atomic-level metallurgical bond between the alloy insert and the steel substrate. The bonding strength is much higher than that of mechanical inlay or spray coating, and the wear-resistant layer is not easy to peel off under severe impact.

[0020] 2. By directly bonding high-hardness alloy materials to the cutting edge where wear is most severe, the method is highly targeted, resulting in an order-of-magnitude improvement in the wear resistance of the tool. Compared with traditional integrally hardened tools, the tool of this invention exhibits significantly enhanced wear resistance.

[0021] 3. The base material does not require overall quenching to high hardness, maintaining good toughness and avoiding the risk of overall tool breakage, resulting in stronger impact resistance. Under the same impact test conditions, the impact resistance of the tool of this invention is improved compared to the tool that is entirely quenched.

[0022] 4. Combining the above advantages, the service life of agricultural machinery blades using this technology can be extended by 3-5 times compared to ordinary blades, significantly reducing replacement frequency and overall operating costs. Calculated based on the agricultural production cycle, this can reduce blade usage costs.

[0023] 5. Vacuum or protective atmosphere brazing effectively prevents oxidation, resulting in stable weld quality suitable for mass production. Furthermore, this process can be extended to different types and materials of agricultural machinery blades, demonstrating broad applicability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention.

[0025] In the figure: 1. Agricultural machinery blade substrate; 2. First alloy insert; 3. Second alloy insert. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Reference Figure 1 The specific embodiment adopts the following technical solution: a novel alloy insert brazing process for improving the service life of agricultural machinery blades, characterized by including the following steps:

[0028] 1. Matrix pretreatment

[0029] Provide agricultural machinery blade base (as attached) Figure 1 As shown in Mark 1, a precise inlay groove is machined into the area of ​​the cutting edge that needs strengthening. The inlay groove and surrounding area are then thoroughly cleaned, degreased, and derusted to ensure a clean welding surface.

[0030] 2. Preparation of alloy inserts

[0031] Prepare alloy inserts that match the shape of the mounting groove (as shown in the attached diagram). Figure 1 (As shown in markings 2 and 3). The alloy insert is made of high-hardness, high-wear-resistant materials such as cemented carbide or high-chromium cast iron, and its shape is designed as a pointed wedge or a multi-faceted pyramid to optimize stress and ensure that the brazing filler metal can be fully filled.

[0032] 3. Assembly and Fixing

[0033] The prepared alloy insert is precisely placed into the inlay groove of the substrate and fixed using a high-temperature resistant clamp or positioning fixture to ensure a uniform and minute gap between the insert and the groove wall. An appropriate amount of solder sheet or solder paste is placed around the assembly; the solder is preferably a copper-based, silver-based, or nickel-based high-temperature solder.

[0034] 4. Vacuum or protective atmosphere brazing

[0035] The assembled workpiece is placed in a vacuum brazing furnace or a brazing furnace filled with a protective gas (such as argon). It is heated at a controlled rate to above the melting temperature of the brazing filler metal and held at that temperature, allowing the liquid brazing filler metal to fully fill the gap between the alloy insert and the substrate under capillary action, thus achieving a metallurgical bond between the two.

[0036] 5. Post-weld treatment

[0037] After brazing is completed, the cooling rate is controlled for slow cooling to release welding stress. Once the workpiece has cooled to room temperature, it is removed and cleaned as necessary. The protruding parts of the alloy inserts are finely ground to form sharp, smooth, and firmly bonded reinforced cutting edges.

[0038] In this specific embodiment, the present invention greatly improves the local wear resistance and overall impact resistance of the cutting tool by brazing high wear-resistant alloy inserts at key parts of the cutting edge. This solves the problems of rapid wear and easy breakage of traditional cutting tools, and can extend the service life of agricultural machinery cutting tools by several times. It has the advantages of high bonding strength, good reliability and significant economy.

[0039] Example 1: A method for strengthening rotary tiller blades, the process of which is as follows:

[0040] 1. Matrix pretreatment

[0041] The standard 65Mn steel rotary tiller blades are selected as the base material, with an initial blade edge thickness of 8mm and a working surface width of 120mm.

[0042] Inverted trapezoidal insert grooves are machined using CNC wire cutting at the two most worn parts of the blade, the main cutting edge and the secondary cutting edge: the groove opening width is 10mm, the groove bottom width is 8mm, the groove depth is 5mm, the groove length is consistent with the cutting edge length (main cutting edge groove length 150mm, secondary cutting edge groove length 80mm), and the groove wall roughness is controlled within Ra1.6μm.

[0043] First, use acetone solution to ultrasonically clean the mounting groove and the surrounding 20mm area for 15 minutes to remove oil stains; then soak in 10% hydrochloric acid solution for 5 minutes to remove rust; finally, rinse with clean water and dry to ensure that there are no residual impurities on the surface.

[0044] 2. Alloy Inlay Preparation

[0045] YG15 cemented carbide (hardness HRA91, bending strength 2100MPa) was selected as the insert material. Based on the size of the insert groove, a perfectly matching inverted trapezoidal insert was machined, with a 0.1mm brazing gap allowance reserved on the surface of the insert.

[0046] The inserts are placed in a vacuum furnace and held at 1000℃ for 2 hours for pre-decarburization treatment to remove the surface oxide layer and improve brazing bonding.

[0047] 3. Assembly and Fixing

[0048] Apply a layer of copper-based brazing paste (composition: Cu60Zn30Sn8P2, melting temperature 810℃) evenly to the inner wall of the mounting groove, with a thickness of about 0.05mm.

[0049] The pre-decarburized carbide insert is embedded into the groove, and a high-temperature resistant ceramic locating pin is inserted from the non-working surface of the blade to fix the position of the insert, ensuring that the gap between the insert and the groove wall is uniform (0.05-0.1mm).

[0050] At the joint between the insert and the substrate, two copper-based solder strips with a width of 2mm are laid to supplement the solder usage.

[0051] 4. Vacuum brazing

[0052] The assembled rotary tiller blades are placed in a vacuum brazing furnace and evacuated to 5×10^-3 Pa.

[0053] Heat to 400℃ at a heating rate of 5℃ / min and hold for 30 minutes to remove residual moisture; then heat to 830℃ at a rate of 8℃ / min and hold for 20 minutes to allow the brazing filler metal to fully melt and fill the gap through capillary action.

[0054] After the heat preservation period, the furnace was cooled to 500°C at a rate of 3°C / min, and then cooled to room temperature along with the furnace.

[0055] 5. Post-weld treatment

[0056] After removing the blade, use an angle grinder to remove any remaining brazing slag from the surface, and then use a diamond grinding wheel to finely grind the protruding part of the insert, so that the cutting edge of the insert and the cutting edge of the base are smoothly transitioned, and the sharpness of the cutting edge is controlled within 0.02mm.

[0057] Place the blade in a 200℃ holding furnace and hold it for 2 hours for stress-relief tempering to eliminate the internal stress generated during the brazing process.

[0058] Performance test comparison

[0059] Test Project Conventional quenched 65Mn rotary tiller blades This embodiment strengthens the rotary tiller blades. Edge hardness (HRC) 52-54 Matrix 42-45 / Mount HRA91 Wear-resistant life (per acre) for field operations 80-100 350-400 Impact toughness (J / cm²) 8-10 12-15 Cutting edge wear after operation (mm) 2.5-3.0 0.5-0.8

[0060] The blade turret of this embodiment has a service life of more than four times that of the unstrengthened blade, and there is no phenomenon of insert falling off or blade chipping.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art 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 appended claims and their equivalents.

Claims

1. A novel alloy insert brazing process for improving the service life of agricultural machinery cutting tools, characterized in that, Includes the following steps: (1) Matrix pretreatment We provide agricultural machinery blade bases and machine precise inlay grooves in the areas where reinforcement is needed. We also perform rigorous cleaning, degreasing, and rust removal on the inlay grooves and surrounding areas to ensure a clean welding surface. (2) Alloy insert preparation Prepare an alloy insert that matches the shape of the inlay groove. The alloy insert is made of high-hardness and high-wear-resistant materials such as cemented carbide or high-chromium cast iron. Its shape is designed as a pointed wedge or a multi-faceted pyramid to optimize the stress and ensure that the brazing filler metal can be fully filled. (3) Assembly and Fixing The prepared alloy insert is precisely placed into the insert groove of the substrate and fixed using a high-temperature resistant fixture or positioning tool to ensure that there is a uniform and small gap between the insert and the groove wall; brazing filler metal is placed around the assembly. (4) Vacuum or protective atmosphere brazing The assembled workpiece is placed in a vacuum brazing furnace or a brazing furnace with a protective gas supply. It is heated to above the melting temperature of the brazing filler metal at a controllable heating rate and held at that temperature. This allows the liquid brazing filler metal to fully fill the gap between the alloy insert and the substrate under capillary action, achieving a metallurgical bond between the two. (5) Post-weld treatment After brazing is completed, the cooling rate is controlled for slow cooling to release welding stress. After the workpiece cools to room temperature, it is removed and cleaned as necessary. The part of the alloy insert that protrudes from the substrate is finely ground to form a sharp, smooth and firmly bonded reinforced cutting edge.

2. The novel alloy insert brazing process for improving the service life of agricultural machinery cutting tools according to claim 1, characterized in that, The brazing filler metal is a brazing filler sheet or brazing paste, and is a copper-based, silver-based, or nickel-based high-temperature brazing filler metal.

3. The novel alloy insert brazing process for improving the service life of agricultural machinery cutting tools according to claim 1, characterized in that, The protective gas is argon.

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