1. Overview of explosive compound development
Explosive compounding (also known as explosive welding), its discovery is a little accidental: in 1944, American L.R. Carl (Carl) accidentally found two thin brass discs with a diameter of 1 inch and a thickness of 0.035 inches in an explosive explosion test. , were welded together due to the sudden shock of the explosion. He was also surprised to observe that the welding interface of the two copper sheets was not a plane, but a regular wave-like interface, and the “waves” of the metal caused by vortices could also be observed at the front of the wave. This wonderful wavy interface is one of the obvious features of the explosive welded bimetallic bond area, similar to that shown in Figure 1. L.R. Carr proposed the use of explosives to weld various metals together. Since then, explosive welding has gradually attracted the interest and attention of scientists. In fact, in the Second World War, when people repaired damaged tanks, they often found that the shrapnel that hit the tank at an angle would be firmly welded to the tank armor, but people had no time to study it during the war. . In 1947, M.A. Lavrentev, a well-known scientist of the Siberian Branch of the Soviet Academy of Sciences, also discovered this phenomenon when he studied the penetration of shaped energy projectiles, which was officially called “explosive welding” in his paper.
After 1958, in order to determine the possibility of explosive welding of metal plates, the United States, Japan, the Soviet Union, Britain, Germany and other countries carried out initial research. Among them, DuPont (DuPont) has studied the explosion welding of large-area plates, and in 1963, the world’s first titanium-steel composite plate of 6 feet * 20 feet was explosively composited. In 1962, the explosive welding research work of Japan’s Asahi Kasei Company and Mitsubishi Heavy Industries has reached an international commercial level. During this period, Teribas of the Siberia Branch of the former Soviet Academy of Sciences and Clausland of the Queen’s University of Northern Ireland made important contributions to the development of this new technology.
my country’s research on explosive compounding began during the Cultural Revolution in the 1960s. When DuPont produced the world’s first commercial explosive composite panel in 1963, the R&D upsurge of explosive composite metal panels quickly emerged in the western industrialized countries, while my country’s explosive composite technology was still blank at that time. According to the national conditions at the time, we had no conditions like other industrialized countries to acquire explosive compounding (welding) technology by purchasing DuPont’s patents or hiring foreign experts. But under the leadership of entrepreneurs represented by Zheng Zhemin, Chen Huojin, Zhang Zhenkui, Li Zhenghua, Shao Binghuang, etc., after going through many difficulties and dangers, they finally created an independent development path that is independent, self-reliant, and fills the gap of my country’s metal explosion composite.
With its unique advantages and characteristics, explosive welding has attracted the attention of scientific research institutes and industrial departments with strategic vision when it started. At that time, Dalian Shipyard, 709 Research Institute (the predecessor of the current 725 Research Institute), Baoji Nonferrous Metal Processing Plant, Shanghai Nonferrous Metal Research Institute, Shanghai Steel No. The Institute of Mechanics and other units have started the scientific research and application practice of metal explosive compounding. After unremitting efforts, in November 1966, the explosion processing group of Dalian Shipyard led by Chen Huojin took the lead in explosion welding successfully the first metal clad plate product in my country, and successfully applied to the water making machine and cooler device of the ship. It has filled the gap in the field of explosive compounding in my country, and it is only 3 years since the first steel plate of DuPont’s explosive compounding.
From the late 1970s to the late 1980s, the theory and practice of explosive compounding in my country were rapidly developing and maturing. Since the Third Plenary Session of the Eleventh Central Committee of the Communist Party of China, with the full recovery of the national economy and the full recovery of industrial production, my country’s shipbuilding, petrochemical, metallurgical and other industrial production departments have successively put forward new requirements for the development and application of metal composite materials. At that time, people still lacked in-depth understanding of the mechanical laws of explosive compounding, and could not give correct and quantitative explanations for the problems and phenomena of the products, and the quality of the products was not stable enough. In response to the requirements of the industry, the Institute of Mechanics of the Chinese Academy of Sciences reorganized its strength in the late 1970s and strengthened its theoretical and experimental research strength. Relevant enterprises also actively organized personnel to formulate relevant topics for explosive composite technology. Dalian Institute of Technology established the Laboratory of Explosion Mechanics and began to train postgraduate students of explosive compounding.
With the joint efforts of the Institute of Mechanics of the Chinese Academy of Sciences and related institutes in the industry, under the guidance of Zheng Zhemin’s explosive mechanics theory on fluid-elasto-plastic models. Through a large number of systematic innovative theoretical and experimental studies, the theoretical analysis and calculation of the motion process of the explosive composite plate under the action of slip detonation, and the theoretical analysis and calculation of the explosive composite parameters of the two-layer or multi-layer composite plate have been completed. A large number of scientific research achievements, such as the mechanism of explosive welding, the establishment of the material weldable ‘window’, the determination of the optimal welding parameter optimization method, the research on the properties of explosives, the research on the microstructure and properties of the bonding interface area, and the research on the formation mechanism of the wavy interface. completed successively. The relevant theoretical work is collected in the book “The Principle of Explosive Welding and Its Engineering Application” (written by Shao Binghuang and Zhang Kai, Dalian Institute of Technology Press, 1987), which is used as a textbook for graduate students of Dalian Institute of Technology. These have enabled the industry to initially master this application technology from the combination of theory and practice, achieved an essential leap in the process of understanding, and made our country’s research on explosive compound theory reach the international frontier level. The relevant research work of the Institute of Mechanics of the Chinese Academy of Sciences also won the first prize of Natural Science of the Chinese Academy of Sciences in 1986.
While in-depth exploration of the mechanism of explosive composite, the industry has also successively solved the supporting technologies for the production and engineering application of explosive composite panels, such as heat treatment of composite panels, defect detection, and hot and cold processing of explosive composite materials. Participated in the formulation of a series of national standards, making explosive composite truly an advanced practical technology, and laid a solid technological foundation for the commercial production of explosive composite materials. With the hard work and joint efforts of colleagues in my country’s explosive compound industry, my country’s explosive compound industry has also entered the world’s advanced ranks in practical application.
With the in-depth development of my country’s reform and opening up, as well as the opening of the market and the maturing of technology, its products have been widely recognized by users. Since the successful application of the 1 million-ton decompression tower in Jinzhou Petroleum No. 5 Plant in 1986, the production of metal explosive composite panels has gradually entered the stage of commercial production. In 1990, Karamay Refinery had an annual output of 1 million tons of vacuum towers, and in 1991, Jinan Oil refinery’s 2.5 million tons of vacuum towers were all built with explosive composite panels from 725 Institute. With the development of my country’s petroleum industry, the application field of explosive composite products has also developed from normal temperature decompression devices to high temperature, high pressure, high corrosion hydrocracking devices and reactors. There are dozens of refineries in the country for distillation units, coke in coking units, coking fractionation towers, catalytic cracking equipment, and chemical equipment such as acid and alkali resistance, vacuum salt production, etc. Most of them are made of domestic explosive composite panels. It marks that the production of explosive composite panels in my country has reached a new level in the practice of organizing scientific research, meeting the urgent needs of production, and solving new material composite technology.
In recent years, the output of various enterprises has been continuously increased, the variety has increased year by year, and gradually replaced the imported rolled composite materials. Products have been widely used in coal chemical equipment, nuclear power plants, food processing equipment, and semiconductor polysilicon production equipment. According to incomplete statistics, in the past 20 years, my country’s explosive composite enterprises have successively provided millions of tons of high-quality metal composite products for military, petrochemical, energy and other key projects.
Since the beginning of the 21st century, the share of domestic explosive composite materials in the international market has also been increasing. The copper/steel and aluminum/steel composite materials exported to Japan have become the preferred material for the induction plate of the subway counter-torque linear motor. favor. In turn, it provides a reference for the application of the subway in the domestic market.
my country’s national economy continues to grow rapidly, and the demand for various metal composite materials has increased significantly, bringing unprecedented development opportunities and considerable economic and social benefits to the explosive processing industry. It is understood that the contract orders of most composite panel manufacturers are increasing year by year, and the production tasks are steadily increasing.
2. Advantages of explosive welding
The biggest advantage of explosive welding is the ability to weld dissimilar metals together. We all know that various metals such as aluminum and steel, copper and steel cannot be welded by conventional methods. Even if they are welded together by some special methods, the welding quality is difficult to guarantee. However, explosive welding can do this, and the strength of the welded interface is often greater than that of the base metal. This is unmatched by other welding methods. Explosive welding combinations commonly used in engineering are: copper-steel, aluminum-steel, copper-aluminum, titanium-steel, stainless-steel, nickel-steel, silver-copper, lead-steel, and bimetallic or Multi-metal composite panels, etc. Another advantage of explosive welding is that it can be welded in a large area, and its welding integrity rate can reach more than 98%. Some steel clad plates can also be continuously rolled to make thin plates with a thickness of only a few tenths of a millimeter. Explosive welding can not only weld flat plates, but also outer or inner welding of metal tubes, that is, to weld a thin metal tube of another material on the inner wall or outer surface of a metal tube of a certain material. Such as copper tube and steel tube, steel tube and titanium tube, titanium tube and red copper tube, tube-tube welding of hard aluminum tube and soft aluminum tube. These are irreplaceable by other welding methods.
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