Use of brazing technology in diamond tool processing

This article briefly introduces diamond tools, tool classification, and brazing technology used in the manufacturing process, analyzes the principle and form of the connection between diamond particles and the substrate, and reviews the corresponding development of brazing technology on the development status of the diamond tool industry at home and abroad. The phenomenon of diffusion brazing of pre-alloyed powder and its beneficial effects are discussed. The synergistic rules of brazing materials, brazing process and brazing equipment are discussed. The development direction of brazing technology for diamond tool industry is proposed for the development of domestic diamond tools and welding industry. Research provides references.

Keywords: diamond, diamond tools, brazing material, brazing technology

1 Diamond tools and their classification

Diamond is a functional material that combines a variety of excellent properties.It is the highest hardness natural material found so far.Its unique optical, thermal, and mechanical properties have strengthened its position in functional materials. Diamond is divided into natural There are two major types of diamonds and artificial diamonds, of which artificial diamonds are divided into single crystals and polycrystalline crystals.The three types of diamonds can be used to make diamond tools.

In recent years, the global production of artificial diamonds has reached 15 billion carats, and China's production of artificial diamonds has steadily ranked first in the world. China's diamond tools have come first, and they have developed rapidly in the past two decades. And a full range of new tools have been developed.

The application fields of diamond tools are very wide, mainly used in stone processing, ceramic modification, geological drilling, oil drilling and mining and mining industries.It also has an important position in the construction, building materials, mechanical processing, optical glass and jewelry processing, and electronic and electrical industries. The demand for diamond tools in the manufacturing industry is increasing, and high-end equipment manufacturing is more and more dependent on the development of diamond tools.High-speed, super-speed, high-precision, ultra-precision cutting and grinding, especially the processing of hard, brittle and high-hard materials Do not open diamond tools. Depending on the application, diamond tools can be divided into sawing tools, grinding and polishing tools, knives, drilling tools, wire drawing dies, etc.

Diamond sawing tools are divided into diamond circular saw blades, diamond row saws, diamond wire saws, diamond wire saws, diamond internal hole saws, etc. according to their shapes. Diamond circular saw blades are currently the most common sawing tools used in the stone and construction industries. Used for cutting granite, marble, ceramic, concrete and other products. In the tide of green manufacturing, diamond circular saw blades are developing in the direction of multi-piece combination saws. Combination saws and row saws are typical; row saws are dozens of diamond saw blades side by side. Installed on the frame of the sawing machine, the cutting efficiency is several times higher than the commonly used large sanding saw, and the cut sheet has a smooth and flat cross section, which can significantly reduce the grinding and polishing workload. Diamond wire saws are generally used in granite and marble mines. Block mining, cutting of reinforced concrete or metal structural parts, and gradually transition to the processing of special-shaped stones and plates. Diamond wire saws can perform precise and narrow slit cutting of hard and brittle materials, and are widely used in semiconductor and photovoltaic cell slicing. And show unique advantages in ceramic, quartz, wood and other processing.

Diamond grinding and polishing tools refer to the general name for bonding diamonds into abrasives with a certain geometric shape with a bonding agent. Diamond grinding tools have high grinding smoothness, high work efficiency, low processing costs, and long product life. Common diamond grinding With grinding disc, grinding block, grinding head, grinding bowl, roller, roller, edging wheel, milling wheel, tangent wheel, honing wheel, honing bar, honing block, etc.

Diamond tools are characterized by extremely high hardness and wear resistance, high elastic modulus, low coefficient of friction, low coefficient of thermal expansion, good heat transfer, and low adhesion to non-ferrous metals. They can be used for non-metallic hard and brittle materials ( (Such as ceramics, graphite, composite materials, etc.) can also be used for precision machining of tough non-ferrous metal materials (such as copper alloys, aluminum alloys, etc.). There are many types of diamond tools, and the performance of various tools varies greatly. There are large differences in preparation methods and application fields. Common diamond knives include diamond turning tools, diamond milling tools, diamond boring tools, diamond broaches, diamond drills and diamond forming tools.

Diamond drill bit is an advanced drilling tool. Diamond drill bit has high drilling efficiency, good drilling quality, light construction labor intensity and low drilling cost. Diamond drill bit is mainly divided into petroleum drill bit, coal drill bit, geological exploration drill bit, and engineering exploration. Drill bits, engineering thin-wall drill bits, glass drill bits, composite material drill bits, etc.

2 Form of diamond connection

Due to the limitation of diamond manufacturing technology, the size of single-grain diamond is small, and diamond is often supplied in the form of fine particles or even fine powder, which brings difficulties to the use of diamond. Because diamond can only fully exert its excellent performance by relying on the base material, its The connection to the base material becomes the key to the application.

Diamond and most metal materials have a natural "incompatible" characteristic. In terms of physical properties, diamonds do not match the physical properties of other materials. In terms of chemical properties, metallurgical incompatibilities and diamond connections are limited.

In the early stages of industrial application of diamond, mechanical inlaying was the main form, such as diamond pens, glass knives, etc.This type of tools required the use of large-grain diamonds.

For diamonds with small grain size, mechanical setting is almost impossible, and fixed plating of plated plating arises at the historic moment. The general process of electroplated diamond tools is as follows: tool carcass processing size inspection, mechanical treatment, degreasing, acid cleaning, rust removal, cold and hot water anodic corrosion Hot and cold water washing, electroplating, diamond thick plating, out of the tank, cleaning and removal of hydrogen inspection finished tools.

The grip strength of electroplated diamond is not high, and the diamond exposure height is low, which affects the cutting force and sharpness of diamond. Brazed diamond tools make up for these defects. Brazed diamond tools are divided into two types: table setting and impregnation setting. The setting tool is brazing the diamond directly to the surface of the substrate, and the impregnation tool is sintering the diamond with other materials into a composite body. The sintering process of the diamond composite is essentially a diffusion brazing process between the diamond and the base material. Carbide alloys are hot-pressed to become composite sheets (pdc), and diamond connections are converted to cemented carbide connections.

3 Presentation of brazing technology in diamond tools

The diamond carcass (commonly known as the blade) is also a diffusion brazing process during sintering. The brazing of diamond tools is divided into three categories: single-layer diamond tool brazing, diamond blade brazing, and pdc composite sheet brazing.

The hot-pressing or cold-pressing sintering process of the diamond cutter head is a typical diffusion brazing process. In the early stage of the production of the diamond cutter head, the melting and diffusion brazing of the high-temperature metal powder with the low-temperature metal powder is generally used to further inlay the diamond; , Activated pre-alloy powders containing carbide-forming elements (chromium, titanium, vanadium, molybdenum, etc.) have appeared. The reactive pre-alloy powder reacts with diamond to form carbides to achieve diffusion brazing or brazing connection, and the formation of carbides is slow. It is a process in which the active elements in the pre-alloyed powder and the carbon elements in the diamond mutually diffuse and migrate.It needs to be kept at a certain temperature for a long time to achieve atomic diffusion and reaction, so the hot-pressing sintering process is easier to achieve this diffusion.

Single-layer diamond tools are generally brazed with active filler metal or nickel-based filler metals.The strong carbides form elements or alloys to achieve a chemical-metallurgical bond between the carcass material and the diamond, which improves the holding power of the filler layer to the diamond. .Single-layer brazed tools have a large proportion of diamond exposure and are not easy to fall off, so single-layer brazed diamond tools have sharp cutting and good chip removal. By orderly arrangement of diamonds, not only the reasonable arrangement of the diamond layer on the surface of the tool, Give full play to the cutting effect of diamond, and greatly reduce the amount of diamond used, reduce tool costs, and improve cutting efficiency.

Diamond brazing has its own unique characteristics. First, the blade is a powder metallurgy product, and there are countless pores in the blade.Second, the blade is a sintered product, and there are oxides on the surface and inside of the blade.The composition of the blade is endless. Similarly, the requirements for brazing materials and processes vary widely.

Due to the limited heating temperature of pcd (generally, the heat-resistant temperature is not higher than 720 ~ 780  ° C), the brazing material mainly uses silver-based brazing material, while the general silver-based brazing material has a lower heat-resistant temperature and is resistant to diamond and carbide. Poor wettability. At present, there are special pdc tool brazing materials, which can meet the requirements of pdc brazing by improving the high temperature strength and fatigue performance of the brazing material and regulating the reasonable brazing process.

4 Diffusion brazing during sintering of diamond matrix

After 1930, diamond circular saw blades were produced using the principle of powder metallurgy.The initial tools were mainly sintered from diamond, high-melting skeleton metal powder, low-melting elementary metal powder and filler materials, among which low-melting metal powder was used as solder. 1960 Years later, the rapid development of diamond tools, more and more units began to systematically study the carcass powder, especially the diffusion brazing effect of powder solder in the form of pre-alloys in diamond tools, which has received more and more attention.

During the use of diamond tools, a large amount of diamond is lost and lost due to the wear of the carcass, but not the wear and tear of the diamond itself, and the utilization rate of the diamond is relatively low. This is because the traditional diamond bit manufacturing is based on the mechanical package of the carcass to diamond. The diamond is fixed by the setting effect.Due to the non-wetting of diamond and general carcass metal materials, the diamond is easily peeled from the metal carcass when the carcass is worn to a certain height during the use of the diamond, which greatly reduces the performance and performance of diamond tools. Life.Improving the ability of the carcass to diamond encapsulation is the most effective technical measure to prevent the diamond from falling off prematurely. In the early stage, the holding force is mainly improved by the mechanical extrusion encapsulation effect caused by the phase change of the carcass powder. Research on the combination of powder and diamond chemistry metallurgy continues to heat up.

Adding strong carbide-forming elements such as nickel, titanium, zirconium, vanadium, chromium, molybdenum, and tungsten to the pre-alloy powder can improve the wettability of the alloy to the diamond on the one hand, and improve the carcass and diamond through the diffusion brazing effect of the sintering process. The chemical bonding force between them increases the cutting edge height of the diamond during the grinding process, improves the cutting efficiency and the utilization rate of the diamond; on the other hand, the pre-alloy powder as a powder solder improves the stability of the diamond bit and Consistency. The State Key Laboratory of New Brazing Materials and Technologies has systematically researched powder solders based on the powder diffusion brazing mechanism, and has developed a series of silver-based and copper based on FBAg625, FBAg737, FBCu14, FBCu17, FBCu18, FBCu70, FBCu423, etc. Base powder solder.

Since the melting temperature range of the pre-alloy powder is compatible with the sintering temperature of the diamond blade, the hot-pressing sintering process is a diffusion brazing process, and the cold-pressing sintering process is an instantaneous liquid-phase diffusion welding process, which can achieve high regardless of the hot-pressing or cold-pressing process. Melting element reacts with diamond wetting under medium temperature environment.

Active pre-alloy powder replaces elemental metal powder for brazing sintering of impregnated diamond composites, cracking the uneven mixing of diamond tool carcass metal powder, low-melting-point elements are easy to lose, high-melting-point active elements are weak, and high vapor pressure elements Technical bottlenecks such as volatile, structural segregation of components, and unstable bonding strength. Optimize the mechanical holding connection of the matrix to the diamond inlay to a composite inlay / brazing composite connection, which improves the diamond height and sharpness of the diamond. When cutting a granite with a cutter head made of pre-alloyed powder developed by the State Key Laboratory of Materials and Technology, the cutting speed can be increased by 1.5 to 2 times, and the saw blade life can be extended by 1.2 to 1.6 times.

5 Brazing of single-layer diamond tools

The direct brazing of single-layer diamond tools is mainly used in the manufacture of grinding wheel dressing pens, measuring tools, stone tools, precious stones or glass engraving tools and diamond grinding wheels, diamond grinding wheels, diamond files. The brazing process can achieve diamond, solder and metal The metallurgical combination of the substrate has a high connection strength, and the cutting edge height of the diamond is far greater than the electroplating process.Therefore, the brazed single-layer diamond tool is sharp, the chip space is large, it is not easy to block during use, and the utilization rate of diamond abrasive particles is high.

Most solder alloys are difficult to wet diamond, and diamond is easily graphitized and oxidized at high temperature, which is limited by the graphitization temperature of diamond. Even in a vacuum environment, the diamond brazing temperature should not exceed 1 050  ° C. Brazing diamond There are few types of solders to choose from.The selected solder must not only have good wetting with the diamond, but also have a combination of chemical and metallurgical effects with the diamond.At the same time, it must ensure the sharpness of the diamond. In addition, the wear performance of the solder must be adapted to the material being processed to ensure the optimal exposure height and long service life of the diamond.

Titanium, zirconium, chromium, vanadium and other carbide-forming elements can well wet diamond, but their melting temperature is too high, and diamond will be seriously graphitized at high temperature; cobalt, iron, and aluminum can effectively wet diamond in liquid state However, it has a strong erosion effect on diamond in the wettable temperature range. At present, two processes are often used to improve the wettability of the solder to the diamond and reduce the thermal damage of the diamond. One is to add a certain Some active elements to improve the wettability and affinity for diamond; another method is to plate the surface of the diamond with metal. When brazing with high melting point solder, the surface metal can effectively protect the diamond and reduce its thermal damage, while improving Wettability of solder to diamond surface.

There are two main types of solders that are added to the conventional alloy solder to form an active element. Copper-based and silver-based series include Ag-Cu alloy solder, Cu-Sn alloy solder, and Ni-Cr alloy solder. Ag-Cu is used. , Cu-Sn low-melting alloy brazing filler metal is mainly considered to reduce the thermal damage of diamond, but the strength of the brazed tool is low and it is difficult to achieve strong grinding. Diamond tools brazed with Ni-Cr alloy have good wear resistance Cutting performance and high temperature resistance.

The methods of brazing single crystal or single-layer diamond tools include: brazing in a vacuum furnace, laser brazing, and high-frequency induction brazing with gas protection. Brazing in a vacuum furnace has high production efficiency, uniform heating, and can be welded with complex structures and relatively small dimensions. Large workpieces; laser brazing uses a laser beam as a welding heat source. The workpiece is locally heated quickly during welding, and the residence time of diamonds at high temperatures is short, which can effectively prevent the graphitization of diamonds. The use of high-frequency induction brazing with gas protection Frequency induction, heating the substrate and the solder alloy at the same time, the heating temperature is high, the heating speed is fast, the temperature is easy to control, it can be locally heated, and it is easy to realize automatic control.

6 Brazing of diamond bit and substrate

The diamond cutter head and the substrate are often connected by brazing to make diamond tools. The sawing, cutting, grinding and drilling tools commonly used today are mainly brazed connections. There are many types of such tools, but the connection joints are Its commonality is the brazing of porous complex composites made of powder metallurgy and alloy steel.

The working conditions of diamond tools are relatively harsh, and they are generally used in high-speed, vibration, and high-temperature environments, so the brazing of diamond cutter heads is more difficult. In order to improve the working efficiency of diamond tools, the requirements for its cutting speed and feed rate are constantly increasing. To improve, this requires diamond tools to have higher brazing strength. In the technical approach to improve brazing strength, brazing material and brazing process rely on each other and promote each other; in the technical approach to improve brazing efficiency, brazing The welding process and brazing equipment support each other and promote each other.

The melting temperature of the brazing filler metal is closely related to the sintering of the cutter head, and the melting temperature of the brazing filler metal should be selected according to the sintering temperature; the strength of the solder should be selected according to the conditions of use of the tool. The brazing material should meet the following conditions when the diamond cutter head and the substrate are brazed. : The melting temperature of the solder should be below 850 ° C, and the lower the better; the solder has good wettability and moderate drifting properties to the diamond bit carcass material and tool substrate; the solder should also have good fatigue Performance and stability, can withstand the transient high temperature of 300 ~ 400  ° C; the brazing process is easy to operate, and universal induction brazing or flame brazing can be used.

The main factors influencing the mechanical properties of the brazed joints of diamond tools are the thickness of the welding lug, pre-weld treatment, heating time, heating speed, heat preservation time, post-weld treatment, etc. These factors determine the wetting condition, porosity, and inclusions. Rate, braze thickness and residual stress in brazing heat-affected zone.

The thickness of the welding lug affects the thickness of the joint brazing joint, and thus the shear strength and fatigue strength of the brazed joint. Experimental research shows that when diamond tools are brazed with the same brazing filler metal composition and brazing process, the brazing joint thickness is between 0.20 ~ 0.28 mm At the same time, the overall performance of the solder joint is better (the thickness of the solder can be reduced to 0.15 mm during re-soldering). When the thickness of the solder joint is small, the solder does not sufficiently wet the joint surface of the tool bit and the tool base, resulting in soldering. The rate is not high, and the strength of the brazing joint is low; at the same time, the elements such as tin, lead, aluminum, iron, tungsten, and titanium in the tool head diffuse and dissolve into the welding joint during brazing, which promotes the brittleness of the brazing joint structure and reduces the strength of the joint When the thickness of the solder joint is too large, porosity is likely to occur in the solder joint, reducing the effective soldering area and reducing the shear strength.

The formation of the brazing seam is closely related to the entire heating process.The heating rate, brazing temperature, holding time, cooling rate and other factors will affect the wettability and porosity of the brazed joint, thereby changing the mechanical properties of the joint. During the production process, often In order to improve the working efficiency, a higher heating rate is used. If the heating rate is too high, the joint will have a large residual stress, which will affect the mechanical properties of the weld. Due to the large differences in the linear expansion coefficients of the components in the diamond bit, such as The linear expansion coefficients of tungsten carbide, tungsten, and chromium are small, while the linear expansion coefficients of elements such as zinc, lead, tin, manganese, and cobalt are large, and the internal stress is generated by the different deformation of each component when heated, but the heating speed is too low. Not only causes low production efficiency, but also exacerbates the oxidation of the braze metal, which has an adverse effect on the diamond tool joints. To solve the problem of heating speed, a two-stage heating process can be used. The workpiece is first heated to 400 ~ 500 ° C, and it is held for a certain period of time before continuing. Warm-up welding. The brazing temperature has a certain effect on the mechanical properties of the joint. When the brazing temperature is too high, the zinc element in the brazing material evaporates and causes porosity.Leads to decreased joint strength; brazing temperature is too low, poor fluidity of the brazing material, easy to produce slag, resulting in false welding, the joint strength is also lowered.

High-frequency vibration during the brazing process can improve the brazing rate and reduce residual thermal stress. Magnet flow technology can improve energy efficiency, reduce energy consumption, and improve work efficiency.

The pre- and post-treatment of brazing has an important impact on the quality of brazing. Before welding, the brazed surface needs to be ground to remove the oxide layer. It is required that the gap between the tool head and the substrate after the grinding is uniform, and the surface oxide layer is often removed. The methods include grinding machine grinding, filing and sand blasting. The diamond tools after welding should be slow-cooled or heat-preserved to minimize the cooling speed after welding, which is beneficial to reduce the thermal stress after welding and a more economical method in production. Asbestos is used for insulation. After welding, a large amount of oxide slag and flux usually remain on the surface of the workpiece. It should be cleaned by sandblasting to avoid corrosion of the workpiece by the flux. After the workpiece is cleaned, the welding quality of the solder joint needs to be checked. The surface of the weld with good welding quality is smooth, smooth and arc-shaped, and there are no obvious pores and cracks.

7 Brazing of diamond composite sheet

Polycrystalline Diamond Compact (Polycrystalline Diamond Compact, PDC for short) is a composite crystal composed of diamond fine powder and binder and cemented carbide sintering under high temperature and pressure conditions. PDC composite has high wear resistance, high With the advantages of elastic modulus, high hardness, isotropy, and relatively high thermal conductivity, PDC tools have become the materials of choice for high-end tools such as petroleum drilling tools, coal mining bits, high-speed and high-precision mechanical cutting tools. One of the key processes of PDC tool manufacturing, the wide application of PDC puts forward higher technical requirements for brazing technology.

The essence of pdc tool brazing is the brazing of hard alloy and tool steel body.Because both hard alloy and tool steel body have good brazing performance, pdc tools have a wide range of choices in terms of brazing material and brazing process. The solder can use silver-based solder or copper-based solder.The process can use induction heating, flame heating and other methods.High-frequency induction soldering has become the main pdc tool currently used in countries around the world due to its advantages such as low environmental pollution and high production efficiency. Brazing method.

Due to the high-precision and high-strength characteristics of pdc tools, brazing accuracy, joint strength and joint quality have become key technologies. There are three main types of failure modes of pdc tools: pdc composite sheets fall off the tool substrate; the composite sheet itself cracks; tools Damage to the substrate. For the three types of failures, the quality of pdc tools is guaranteed through optimized brazing materials and suitable brazing processes.

At present, there are commercial pdc special solders.The common characteristics of these solders are high silver content, and nickel, manganese, cobalt and other elements. They have good wettability to hard alloys and high brazing strength. The temperature difference between solid and liquid phase is generally controlled at 50 ~ 80  ° C.

In order to solve the problem of composite sheet peeling, engineers and technicians are committed to research on improving the properties of brazing materials, such as replacing BAg40CuZnNi, BAg45CuZn, BAg50CuZn and other brazing materials with higher strength. However, the brazing process has been ignored. "Fragile" defects, the use of brazing materials and brazing processes with excessively high melting temperatures will lead to cracks, chipping, chipping, and chipping of the composite sheet. Studies have shown that high-quality PDC allows the brazing temperature to not exceed 780 ~ 800  ° C, the brazing temperature allowed by general quality PDC does not exceed 750  ° C.

8 Diamond tool brazing equipment and technology

Due to the variety and variety of diamond tools, the brazing processes and brazing equipment derived from them are endless. Flame brazing, salt bath brazing, induction brazing, resistance brazing, furnace brazing, vacuum Brazing and laser brazing are competing on the same stage. At present, the mainstream technologies are induction brazing and vacuum brazing [21-22].

Flame brazing is a brazing method that was developed very early.The equipment required is simple and light, the gas source is wide, and the process cost is low.However, its heating temperature is not easy to control, and it is gradually eliminated by the mainstream market.

Salt bath brazing has fast and uniform heating speed, high brazing efficiency, and the base metal is not easily deformed during brazing, which is suitable for mass production. However, a large amount of flux remains on the workpiece after salt bath brazing, and a large amount of wastewater is generated after cleaning It also pollutes the environment.In addition, salt bath brazing equipment is expensive, the process is complex, and the production cycle is long.More importantly, the green manufacturing wave is eliminating the impregnation brazing of diamond tools.

High-frequency induction brazing has fast heating speed and high brazing efficiency; easy operation and low labor intensity; can braze various shapes and multi-tooth workpieces; when using automatic feeding, atmosphere protection or vacuum induction brazing, the joint has a good The appearance and quality of brazing. This method not only has low production cost in one welding, but also the substrate can be re-welded and reused. With the increase of diamond tool manufacturing labor costs and the improvement of diamond tool brazing quality stability requirements, automatic The induction brazing process has gradually become the main method for welding diamond sawing tools.Automatic induction brazing of diamond tools can achieve automatic tooth splitting, automatic identification and picking of cutter heads, and automatic welding of welding blades. It has high welding accuracy, strong brazing joints, and long service life. Advantages such as long, one person can operate multiple machines, greatly reducing labor costs.

Resistance brazing is often used for honing rod brazing, and its weld quality is good; but because the overall temperature of the cutter head is high, which affects the service life of diamond, a few companies currently use this process.

Furnace brazing (continuous atmosphere protection furnace brazing) is mainly used for the production of small saw blades and special-shaped diamond tools. Generally, hydrogen and nitrogen generated by the decomposition of ammonia are used as reducing gases. The heating speed is slow and the temperature is uniform, and the brazed joint is beautiful and quality. Reliable, bright workpiece surface, high production efficiency, low welding cost, suitable for batch production.

Vacuum brazing generally uses resistance furnace radiation heating, high production efficiency, and uniform heating can weld diamond tools with complex structures and large sizes. At present, vacuum brazing single-layer diamond tools are widely used in rest tools, grinding wheels, stone tools, glass For the manufacture of tools, vacuum brazed multilayer diamond tools have good industrial application prospects.

In recent years, the laser brazing method has gradually been applied to the manufacture of single-layer diamond tools. During laser brazing, the workpiece is locally heated quickly, and the diamond stays at a high temperature for a short time during the welding process, which can effectively prevent the graphitization of diamond. The brazing process can also achieve the orderly arrangement of diamond particles, high heating efficiency, accurate temperature control, processing of complex curved surfaces, high degree of automation, and good operating environment. Laser welding is used to weld large-sized and shaped complex workpieces. It can also avoid the proximity effect and skin effect of high frequency induction brazing.

9 Development Trend of Diamond Tool Brazing

The brazing of diamond tools has formed a professional type of work, which consumes nearly 1,000 tons of brazing materials each year. There are tens of thousands of domestic employees. The industry is flourishing, and the development trend that can form a consensus has the following five points: automation, Greening, compounding process, quality, and economy.

Automation and greening are the basic concepts and important projects of Made in China 2025. The labor cost of the diamond tool industry is increasing, and even endangers the development of the industry. Automated brazing is a common demand in the industry. All products with larger batches all require automated brazing. Welding development.At present, the automatic brazing of saw blades has become mature, and other products of automatic brazing equipment are on the horizon.

The connotation of greening includes reducing emissions, saving materials, improving energy efficiency and reducing energy consumption. Diamond tool brazing has developed rapidly in terms of material reduction and energy saving, but in terms of using cadmium-free solder, flux-cored solder, and reducing the amount of flux. Development is slow. Diamond tools (such as drills, picks, saw blades, knives, etc.) are dissipative products, in which the solder will be lost with the normal work of the tool, and the elements such as lead and cadmium in the solder will be scattered into the air. , Soil and water, pollute the environment, part of it is ingested into the human body and harm human health.

The composite brazing process includes: flame-induction, induction-furnace welding, furnace welding-induction-flame, and other brazing methods, which can achieve complex, large-size tools for rapid all-position brazing, shorten brazing time, and improve tool durability. And reliability to extend tool life.

Quality improvement requires a longer fatigue life of the brazed joint, and the defect in the brazing joint is the main factor affecting the fatigue life. Therefore, with the extension of the life of superhard tools, it is required to continuously reduce the defect in the brazed joint and improve the brazed joint. The quality of the brazing material is an important factor affecting the formation of defects when the brazing material and process are appropriate.

Economy is the eternal demand of the manufacturing industry. Low silver solder, copper-based solder, composite solder and prefabricated solder are the main directions to save the cost of solder; efficient soldering process and highly reliable soldering technology are to reduce the cost of soldering. Another way.

10 Conclusion

(1) There are various types of diamond tools, and brazing technology is a key technology in the manufacture of various tools.

(2) There are four main types of brazing technology used in the manufacture of diamond tools: diffusion brazing in sintering of the blade, brazing of the blade, single-layer diamond tool brazing, and pdc tool brazing.

(3) Pre-alloyed powder is an effective way to improve the comprehensive performance of diamond cutter heads. Active pre-alloyed powder can synergistically improve the sharpness and service life of diamond tools.

(4) The key to diamond blade brazing technology is personalized soldering and efficient brazing process.The key to pdc tool brazing technology is high-quality brazing material. The key to single-layer diamond tool brazing technology is equipment and brazing material.

(5) The brazing of diamond tools is developing towards automation, greening, compound technology, high quality, and economy.

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