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Synthetic diamonds, called synthetic diamonds. The earliest time in the country to know this information can be traced back to the late 1950s of the last century. At that time, many units knew that diamonds could be artificially synthesized, but they were not implemented because of the lack of high-voltage equipment. In 1963, the first synthetic diamond was successfully developed by the General Machinery Research Institute, the Abrasives Grinding Research Institute and the Institute of Geological Sciences. In 1966, the Institute of Foundry and Forging Machinery, in close cooperation with the Institute of Abrasives Grinding, successfully produced a six-faceted synthetic press, which created conditions for the intermediate test and industrial production of synthetic diamond in China, and created the artificial diamond industry in China. The first. It is exactly fifty years ago.
The Chengdu Tool Research Institute began to involve ultra-hard materials, which was closely related to the specific circumstances of the environment and tools at that time. The personnel engaged in the process are unable to carry out their work for a long time, mainly because they lack equipment conditions and can only cooperate with various tool factories. If the tool factory has the conditions, the problem is better. If some new projects require the factory to invest and purchase equipment, the factory is not willing to take risks without seeing the benefits or prospects. In addition, some cognitive problems also affect the development of the tool industry, that is, the tool research institute only serves the tool industry, or the mechanical processing industry in the country; it is based on the structure and design of the tool, or it must be comprehensive. So in the mid-1960s, laboratories such as cemented carbide and ceramics were established. Some technicians have also turned from material engineering to material research.
At that time, there were only two technicians involved in this field. I and another technician, Feng Shiguang. The latter participated in the Cubic Boron Nitride Collaborative Group led by the Sichuan Provincial Science and Technology Commission to further collect relevant information, while I used the better conditions of foreign languages ​​to browse foreign materials. By looking at foreign materials (such as RH Wentorf, FP Bundy in the United States, è‹è”. Верещагин, Ð. Е. Филоненко et al. patents and articles) in the United States, it is found that cubic boron nitride appears after synthetic diamonds. A new type of tool material with great potential. So since 1973, the group has established a boron nitride laboratory. The establishment of the laboratory took two years and was completed in 1975.
In the process of establishing the laboratory, we mainly carried out the following work: further collecting data to understand the practice of the hexagonal boron nitride conversion square structure, and further sintering of the synthesized cubic boron nitride single crystal (that is, the polymerization at that time) Crystal) and the case after becoming polycrystalline. Since we have no conditions and lack of perceptual knowledge in this aspect, I went to the sixth grinding wheel factory in the suburb of Guiyang in 1974 to study and learn, and provided 100 polycrystalline cubic boron nitride sintered bodies from Liusha. We made a turning tool and conducted a preliminary cutting test. The main purpose is to understand the possibility, prospects and problems of using cubic boron nitride as a cutting tool material, so as to clarify the future path. As a result of this work, we wrote the article "Preliminary Exploration of the Application Range of Cubic Boron Nitride Turning Tools". I remember when I left Liusha, I said to Li Zhongqi, a partner of Liusha. If you want to use cubic boron nitride as a tool material, you must take the road of composite sintering with cemented carbide. The time should be 1974. What is more important is that this judgment was put forward after our personal practice, and it is not from foreign materials.
In the mid-1970s, China’s big environment was a mess. As a scientific and technical personnel, we also have to participate in some political activities. Therefore, the work of the subject matter is intermittent and the progress is not very fast. The topic "The development of superhard composite blades", which was proposed in 1975, was not officially carried out until 1978. It should be said that this has nothing to do with the change of the country's entire policy.
Before the official start of the "Development of Superhard Composite Blades" (Ministry Control Project), the Tool Institute also completed a provincial science and technology project: "Cubic boron nitride and its polycrystalline sintered body", the time span should be 1973- 1978. The project won the 1978 National Science and Technology Conference Award and the Second Prize of Science and Technology Achievements of the Sichuan Revolutionary Committee. In 1985 and 1989, it was separately reported under the name of “Cubic Boron Nitride Polycrystal Mechanism and Applicationâ€, and was awarded the scientific and technological progress of the Sichuan Provincial People's Government. The second prize and the third prize of the National Science and Technology Progress Award, I am a participant in the project.
The topic of "Development of Superhard Composite Blades" was proposed in 1975, and the time for becoming a ministerial subject was 1978 (the beginning and ending time was April 1978 - December 1980). The main research contents of this subject are: the composite sintering mechanism of synthetic diamond and cemented carbide, cubic boron nitride and cemented carbide; the influence of temperature and pressure parameters and assembly methods; and the cutting test after the composite sintered body is made into a tool. A composite sintered body of synthetic diamond and cemented carbide, the grade is designated as FJ; a composite sintered body of cubic boron nitride and cemented carbide, the grade is designated as FD. After the completion of the project, he wrote the "Study on the High-pressure Sintering Mechanism of Superhard Materials and Cemented Carbide Composites", and read it at the Second National High-Voltage Physics Symposium organized by the Chinese Academy of Sciences Physical Society, and included the proceedings ( The second national high-pressure academic seminar drawdown article 21, 2.10). The technical committee's evaluation of the subject is: the first successful synthesis of cubic boron nitride and cemented carbide composite sintered body in China, filling the domestic gap; breakthrough in technology. In 1982, the project won the second prize of major scientific and technological achievements in Chengdu and the third prize of the Ministry of Machinery Industry.
The project "Development of Superhard Composite Blades" was completed from April 1978 to December 1980 and lasted for more than two years. Since then, the "Intermediate Test of Superhard Composite Blades" (Ministry Control Project) has been started since 1981. The central task is to further solve the FJ synthetic diamond and cemented carbide and FD cubic nitrogen based on the results obtained in the previous project. The transition of boron and cemented carbide sintered bodies to mass production includes designing a turning structure suitable for this new material, perfecting process specifications, and stabilizing product quality. It is worth mentioning that in carrying out this issue, we have adopted the practice of side research, side trials, propaganda, promotion, and production. The purpose is to further expand the scope of application and ensure that the produced tools can have A stable market. Therefore, he participated in many national publicity and promotion conferences. While promoting the performance of cubic boron nitride tools, he also understood the needs of many users and found a direction for the next step of production. Due to the walking method of several legs, in the course of carrying out this subject, nearly 200,000 production values ​​were created for the tool research institute, and the bonus problem of the workers was solved.
The products in the "Intermediate Test of Superhard Composite Blades", FJ Composite Synthetic Diamond and FD Composite Cubic Boron Nitride Series Tools have won the Excellent New Product Certificate and Golden Dragon Medal issued by the National Economic Commission. The time spent on this topic was 1981-1986, which was interrupted for two years because of the purchase of a six-sided press (the reason for the purchase is not described here). At that time, the leadership of the Machine Tool Bureau, although very supportive, had made a special call to Qinghai a machine tool, but unfortunately after arriving at the factory, it was known that the factory had stopped production of such equipment. In desperation, I had to find another way. Finally, through the acquaintance relationship, an old six-sided roof was found in Sichuan Province. In this way, the problem can finally be carried out.
At the same time as the topic of "Development of Superhard Composite Blades", several other topics have been inserted: "Composite cubic boron nitride products - turning tools, milling cutters, boring tools", "composite synthetic diamond products - drills, turning tools" , Scythe" two control topics. In these two projects, only the design, manufacture and test of the composite cubic boron nitride end mill were completed, and other contents were not completed due to the conditions at that time.
In addition to the above-mentioned topics, two "seven-five" research projects have been inserted: "Study on Precision Machining Process of Spray Welding Wear Parts" and "Research on Precision Machining Process of Impurity Pump Overcurrent Parts". The former project, because the Tool Research Institute participated in the National Thermal Spraying Collaborative Group, is a member of it, mainly responsible for solving the post-processing problems of coatings, so it has cooperated with many manufacturers. Here are a few specific examples.
1. In October 1982, the early turning test of the spray-welded layer (G112 alloy powder) with FD cutter was started at Boshan Pump Factory. The results show that the processing quality is fully in line with the requirements, the processing time is only 0.5 hours, and the original grinding requires 48 hours (6 classes).
2. At the beginning of 1983, we also used the FD tool to perform the turning performance on the sprayed welding layer at the Shanghai Industrial Exhibition Tool Museum. It also received good results.
3. In April 1983, Tianjin held a “Technology Exchange Conferenceâ€, referred to as “Double Fairâ€. We are involved in the technical research project of thermal spray materials. Thermal spraying technology is a process of spraying a layer of high-hardness material on the surface of a part to improve the wear resistance and corrosion resistance of the part. We process the metered pump plungers that are sprayed and use FD cutters to directly push the outer car to the product size on the lathe. The test results show that it took 10 minutes to finish processing and the surface finish reached â–½7. When grinding with a grinding method, it takes at least 8 hours to reach a plunger (up to â–½7). The processing cost has been reduced from the original 24 yuan to 1 yuan and 5 yuan. This has made many old workers who have been engaged in cutting technology for decades, and they are full of praise. After the meeting, the group accepted the interview of Li Ruihuan, the mayor of Tianjin at that time, and conducted a publicity report on the Tianjin Daily on April 10, 1983.
4. In November 1986, a scientific research project issued by the State Economic Commission to the Ministry of Water Resources and Electric Power and the Ministry of Water Resources and Electric Power to the project was submitted to the Beijing Water Conservancy and Electric Power Design Institute. The cooperation unit is the Yingxiuwan Hydropower Station in Guan County, Sichuan. Spray welding was carried out by the power station. After the processing, the Beijing Tool Research Institute, Zigong 764 Factory and Chengdu 420 Factory were invited to discuss the site, but they did not dare to undertake. Later, the processing task was entrusted to the Aviation Industry Department 611. We have cooperated with us to know that the composite cubic boron nitride tool has obvious effects on this material, so we cooperate with the tool research institute to use FD composite cubic nitride. The boron tool completed the machining task within one month, the quality (accuracy and surface roughness) met the requirements, and the requirements and recommendations for the use of cubic boron nitride tools for roughing were put forward. Due to the large size of the workpiece, a large-sized FD composite cubic boron nitride insert is required to improve the processing efficiency.
In addition to the actual application, several articles were published during this period: In June 1980, "Preliminary Test on Spraying Spray Welding Materials with Cubic Boron Nitride Turning Tools" was published in "Tool Technology". It is the earliest report on this aspect, prior to GE Corporation of the United States; in April 1982, “Superhard Tool and Its Application†was published in “New Technology and New Technologyâ€, in which the processing of spray coating was included in CBN. The scope of application of the tool; in June 1986, in the "Mechanical Workers" (cold processing), introduced "turning of the thermal spray spray coating", as a mature experience to promote.
There are many times and content about the various conferences and the personal promotion that the factory participated in during this period of time, and it is impossible to describe them one by one. In general, through the promotion experiment at this stage, the scope of application of the FJ composite synthetic diamond and FD composite cubic boron nitride series tools has been basically clarified. In addition to the thermal spray welding materials described above, copper (motor rectification) is also included. Sub), mechanical carbon, FRP, various non-ferrous metals, new composite materials, hardened steel, various high-hardness cast iron (such as chilled cast iron) and some metal difficult-to-machine materials. The factory involved in the organic vehicle and vehicle factory, the non-ferrous metal rolling plant, the motor factory, the instrument factory, the electric carbon factory, the automobile factory, the petrochemical plant, the water pump factory, the factories of various military systems, and the production plants with difficult processing problems.
In 1984, led by the Mechanical Science Research Institute of the Ministry of Machinery Industry, the mechanical system "Difficult to Process Material Cutting Technology Communication Network" was established. The participating units included various institutions of higher learning, central and local professional research institutes, and machinery manufacturing in various provinces and cities. plant. I would like to carry out some promotion and research activities in the difficult field of domestic processing, so that the emerging superhard tools can be recognized and used by more people, and play some role in improving the level of domestic mechanical processing, but for some reasons, no results. And the end. In November 1983, I received a letter from a certain institute of the Seventh Machine Department and three institutes, and introduced me to some situations at the North China Technical Exchange Conference. It is said that our FD tool can be used to process 9Cr18 steel with quenching hardness up to HRc 62-65. The surface roughness is up to ▽8, which can be worn by the car and has good durability. However, the cubic boron nitride tool produced by another factory in Beijing is too low in durability and the vehicle does not have one part. I read the letter, although I am happy that our products can be used for production, but also have some apologies, "each is its master", "involuntarily." In 1986, in a "Ningxia Hui Autonomous Region Workers Technical Cooperation Committee Document" (Ninggong Jizi [1986] No. 4), there was such a paragraph: "Chengdu Tool Research Institute's compound cubic boron nitride turning tool, Can cut a variety of hardened steel (HRc 60-67), wear-resistant cast iron, spray materials, special alloys and non-ferrous metal light processing (▽7-▽10). On-the-spot turning hardened steel and carbide, so that delegates Some of the delegates said: "This kind of knife can turn hard alloys. I have never seen it before, but I have never heard of it. It’s unimaginable. It’s just a god..." This should explain the popularization. What is the meaning?
Here are a few more prominent and unprecedented examples to illustrate the contribution of superhard tools, especially FD composite cubic boron nitride tools, to the domestic machinery industry.
(1) In March 1987, Lanzhou Petrochemical Machinery Industry Co., Ltd., a sub-factory of the company, did not stop the repair of the exciter slip ring of the 100,000 kW generator set (due to long wear and tear, too large radial runout), and achieved success. The unit has a rotational speed of 3,000 rpm and a slip ring diameter of 200 mm, resulting in a cutting speed of 1,885 m/min and a 0.11-0.23 mm/rev. The other tools burned up and could not be used at all. A long-time mechanic of the plant said that he had never seen such a high cutting speed to process A3 materials, which gave him a new understanding of FD cubic boron nitride tools. It should be said that non-stop repair is an innovation, and the use of nearly 2000 m / min cutting speed to process A3, I wonder if it has also created the Guinness World Record.
(2) The protective cover of the artificial satellite is made of special composite materials, which is resistant to high temperature and impact, and is difficult to process. Because the size of the workpiece is very large, the dimensional accuracy and geometric accuracy of the workpiece are very high. When the original tool is used for machining, the tool wear resistance is not enough, and it can only be compensated by adjusting the machine tool. This is of course a stopgap measure. After switching to a composite synthetic diamond tool (FJ tool), the tool has a sufficient wear resistance, so that the workpiece has a reverse taper, that is, there is no need to adjust the machine tool to accommodate the wear of the tool, and the cutting speed is also It has been improved and productivity has been improved. The testing of such materials, although carried out in the aerospace industry, is widely used in other manufacturing industries, so this experiment should be said to have universal significance.
(3) The problem of mechanical processing of pure nickel parts in the aerospace industry has always been a headache. The original processing method, the conditions are extremely poor, due to the rapid wear and tear of the tool, the noise during processing is as high as 100%. The workers must work with the earplugs in the closed room, and the processing quality is not ideal, it is not easy to guarantee, but no one. Go to research and solve. According to the excellent stability of cubic boron nitride, we believe that when cutting some special materials, there should be obvious effects. The test results prove that the above judgment is correct. After processing with the FD series of composite cubic boron nitride tools, it is not only no noise, but also greatly improves the surface quality of the parts. The performance was completed by many university professors personally, and they were affirmed by them and the factory. Later, the space system itself held an appraisal meeting for this purpose.
(4) In order to understand the stability of cubic boron nitride, we did some experiments. This kind of test may not be of interest to technicians who are solely engaged in cold working. On the basis of experiments and practice, we put forward the idea that "cutting is a special form of micro-zone thermal processing". The intention is to end the situation of “cold†and “hot†separation in traditional disciplines (schools, factories, and even some management institutions have historically been divided into cold and hot processing). Observing the cutting process with the "cold" and "hot" unified cutting viewpoints can overcome many of the shortcomings of the traditional cutting principle and can not guide the actual machining. Using this point of view, it has very important guiding significance for solving the wear mechanism of the tool and what kind of tool is used in different occasions. Of course, the emergence of a new viewpoint or theory, there are always people who agree, and some who oppose it. There are many examples of this in history. In fact, the root of the problem is the side effects of the discipline of modern science. The purpose of sub-discipline should be to make the scope of scientific experiments smaller and minimize the variables in the experiment so that it is easier to find out the objective laws of things. However, over-emphasizing the discipline will constrain people's thinking and is not conducive to thinking and understanding the whole thing. The above solution to the problem of processing pure nickel parts is based on this theory. This view, or metal cutting, is a special form of micro-zone thermal processing. Professor Lei Tingquan, a professor of thermal processing at the alma mater, and Professor Yuan Zhejun from the cold-working profession (who served as a tool between 1957 and 1961) The opinions of the deputy director of the institute have been recognized by them. After reading our performances on pure nickel, I made a suggestion to Professor Yuan Zhejun (there were many representatives and teachers from other universities at the time), which suggested that the alma mater should add a little hot processing to the cold processing course. The curriculum will make the students' ideas more open. He said at the time that we can cooperate to bring graduate students. In the third issue of the Journal of Metal Science and Technology in 1985, we published all the information on this test, entitled "Study on Diffusion Wear of Cutting Tools in Nickel Cutting - Application of Phase Diagrams in Metal Cutting".
In 1987, the General Electric Company's Super Abrasives delegation visited the Tool Research Institute. The visiting members have US headquarters, and most of them are members of the office in Tokyo, Japan. We exchanged at the meeting, and later the two sides used their own tools to perform the cutting performance. The processed test piece was a chilled cast iron roll. This comparison test was carried out by specialists and recorded the cutting conditions, tool wear and rough surface roughness. The results show that our FD composite cubic boron nitride tool is not as durable as the US GE company, and the surface quality is slightly better than that of foreign countries.
After the event, it took another period of time to set up an office to cooperate with GE. During the period of cooperation with GE, the United States participated in many meetings and made efforts to open the market for American products in China. In addition, they also translated a set of product promotional materials: "COMPAX composite synthetic diamond blank and BZN cubic boron nitride composite sheet."
In December 1988, we should visit the United States for a short time. I looked at the production and equipment in the Ohio headquarters. The impression I gave was that the scale was not large, and it was similar to ours (maybe some places didn't show it to me). I was lucky enough to participate in their celebrations at the time. When I was about to leave the United States, GE sent me a certificate. The certificate stated: Proof that Cao Zhenyu successfully completed the GE Superabrasives Machinery Processing Seminar (Seminar) at: December 5, 1988 On the 9th, the signatory: EJ Russell; TJ Broskea; DM Williams. In this way, all the cutting tests that we have carried out in China are included in the scope of GE. After leaving the United States, he went to Japan to visit GE's office in Tokyo. Several of them were the people who visited the tool. The laboratory in Tokyo is not large, and it seems that it is mainly for GE's cutting test.
After returning from abroad, although I have maintained contact with the user for a period of time and handled several contracts, basically no work has been done. The customer's need for super-hard tools is done by the technicians who are later assigned to the super-hard tool laboratory until the location of the tool is moved out of the city.
The above introduction basically reflects the contribution of the Tool Research Institute to the country in the field of superhard materials. All content is documented. I believe that in order to commemorate the 50th anniversary of the development of China's superhard materials, China's superhard materials industry will certainly continue to gain new achievements like the military industry, further proving that "science and technology are the primary productive forces", for the constant We will make our own contribution to improving our country's ability to machine processing and developing our country's social productivity. (This article is excerpted from "China's Superhard Materials Industry Fifty Years")
A new approach to the application of super-hard composite tools
Abstract Superhard materials, as the name suggests, are some of the most extremely hard materials. The first such material that humans know is diamond, or the so-called diamond. The natural diamonds extracted from the ground are mostly single crystal structures. The larger the crystal, the higher the economic value, and the weight is in carat...
Superhard materials, as the name suggests, are some of the most hard materials. The first such material that humans know is diamond, or the so-called diamond. The natural diamonds extracted from the ground are mostly single crystal structures. The larger the crystal, the higher the economic value. The weight is in carats (1 carat = 0.2 g), mainly used in jewelry, such as diamond rings. Drill a necklace and so on. The finer particles can be used in the industry to make tools, cut non-ferrous metals, or as an abrasive to make various abrasive tools.