The method of smelting high-temperature alloys in a vacuum induction furnace is to place the induction furnace in a vacuum and melt and refine the alloy through high temperatures. This method is called vacuum induction melting (VIM) of high-temperature alloys. At present, almost all highly alloyed high-quality high-temperature alloys are melted once using vacuum induction melting, and then melted twice or even three times.
In the 1940s, atmospheric pressure smelting limited the use temperature of high-temperature alloys to about 750°C. However, the invention of vacuum technology in the 1950s improved the quality of high-temperature alloys and improved the thermal processing properties, further increasing the content of alloy elements, thereby increasing the use temperature of deformed high-temperature alloys to about 950°C. Subsequently, vacuum metallurgy technology was used to develop cast high-temperature alloys. Under the same composition, the service temperature of cast high-temperature alloys is about 30°C higher than that of wrought alloys. Since casting eliminates the difficulty of hot processing, the content of strengthening elements such as Al, Ti, Nb, and Ta can be further increased, thereby increasing the use temperature by 20°C. Therefore, vacuum smelting plays a very important role in the development of high-temperature alloys.
In the 1920s, vacuum induction furnaces began to be used in industry. In 1923, Germany used a vacuum induction furnace for the first time to smelt Co and Ni alloys, with a capacity of 4 tons and a power of 350 kilowatts. Since then, vacuum induction furnaces have gradually developed.
In 1958, a vacuum induction furnace with a capacity of 1 ton began to melt high-temperature alloys. In 1961, a vacuum induction furnace with a capacity of 6 tons was also put into use. In 1968, a vacuum induction furnace with a capacity of 60 tons was officially used in production in the United States, with a vacuum degree of up to 1.33×10-2Pa. In 1956, our country imported two 10kg small vacuum induction furnaces from abroad. One of them was owned by the Institute of Metallurgy, Chinese Academy of Sciences. It was used to smelt nickel-based casting high-temperature alloys. It played a very important role in the research of early high-temperature alloys. Some special domestic The steel plant introduced a 3/6-ton vacuum induction furnace in the 1980s. In recent years, it has been equipped with a 12-ton large-scale vacuum induction furnace that is the most advanced in the world. This 12-ton VIM1400 vacuum induction furnace was introduced from Germany. Its ultimate vacuum degree can reach 0.01Pa and the air leakage rate can reach 27Pa.L/S. It can accurately control the chemical composition of the alloy, especially for elements with a greater affinity to oxygen (such as Al, Ti, B, Zr, Mg). An advanced electromagnetic stirring system speeds up the melting process and improves temperature and ingredient uniformity. During pouring, the purity of the molten steel is ensured by using two layers of slag retaining and ceramic filtration. The smelting parameter curve in the furnace can be automatically controlled. The on-site data collection system can display and automatically record the smelting process parameters at any time, such as power, frequency, vacuum degree, air leakage rate and temperature. These advanced technologies ensure the stability of product quality and provide long-term, true and complete traceability for products.
The following will introduce the characteristics and principles of high-temperature alloy melting in vacuum induction furnaces. The vacuum induction furnace introduces high-frequency current into the smelting material through the principle of induction heating, causing it to generate resistance heating and reach the melting temperature. At the same time, the vacuum environment can prevent the contamination of impurities and oxides and improve the purity of the alloy. The metallurgical chemical reaction of high-temperature alloys melted in a vacuum induction furnace is also an important aspect. Under high temperature conditions, the elements in the alloy will undergo various chemical reactions, thus affecting the composition and properties of the alloy. Therefore, it is necessary to control the temperature, pressure and alloy composition during the smelting process to ensure the quality of the final product.
Vacuum induction furnace equipment is also very important. In addition to the furnace itself, it also includes the power supply system, induction coil, electromagnetic stirring system and vacuum system. These equipment need to ensure stable working conditions to ensure the smooth progress of the smelting process. The smelting process is also a very critical link. During the smelting process, parameters such as furnace temperature, current, protective gas, and stirring speed need to be controlled to achieve the ideal smelting effect. At the same time, it is also necessary to pay attention to the slag formation inside the furnace and the waste gas treatment outside the furnace to protect the environment and save energy.
In addition to deforming high-temperature alloys, vacuum induction furnaces can also be used for melting and casting high-temperature alloys. Compared with deformed superalloys, cast superalloys have higher service temperatures under the same composition. The smelting process of cast high-temperature alloys is relatively simple, and the content of strengthening elements can be further increased, thereby increasing the service temperature of the alloy. During the smelting process of casting high-temperature alloys, through reasonable smelting processes and equipment, the purity of the alloy and the uniformity of the composition can be ensured, thereby obtaining high-quality castings.
In the actual smelting process, vacuum induction furnaces are widely used in the production of various high-temperature alloys. For example, nickel-based alloys, cobalt-based alloys, iron-based alloys, etc. These alloys are widely used in aerospace, energy, chemical and other fields. Through smelting in a vacuum induction furnace, high-temperature alloy materials with good performance and high purity can be obtained to meet the needs of various projects.
In short, the melting technology of vacuum induction furnace plays an important role in the field of high-temperature alloys. Through vacuum environment and high-frequency induction heating, the melting and refining of high-temperature alloys can be achieved. The equipment and processes of the vacuum induction furnace ensure the quality and purity of the alloy. With the continuous advancement of technology, vacuum induction furnaces will continue to play an important role in the R&D and production of high-temperature alloys.
Tianjin Anton Metal Manufacture Co., Ltd. is a company specializing in the production of various nickel-based alloys, Hastelloy alloys and high-temperature alloy materials. The company was established in 1989 with a registered capital of 10.0 million, specializing in the production and sales of alloy materials. Anton Metal’s products are widely used in aerospace, chemical industry, electric power, automobile, nuclear energy and other fields, and can also provide customized alloy material solutions according to customer needs. If you need to know the price consultation of alloy materials or provide customized alloy material solutions, please feel free to contact the sales staff.
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Post time: Nov-18-2023
