What Is Involved in the Continuous Casting of Steel?

Continuous casting is an advanced casting method. Its principle is to continuously pour molten metal into a special metal mold called a crystallizer. The solidified (crusted) casting is continuously from the other end of the mold. Pull out, it can get castings of any length or specific length. The development of continuous casting is an important means for structural optimization of China's metallurgical industry, which will fundamentally change the current situation of low efficiency and high consumption of metal materials production in China, and promote the development of product structure towards specialization. The development of advanced continuous casting technologies such as near-net-shape continuous casting, single crystal continuous casting, high-efficiency continuous casting, and hot casting and hot charging of continuous casting slabs will be very active, and it will drive the development of a series of new materials ^[1] .

For more than a century, under the pressure of industrial restructuring, tight raw materials, energy shortages, increasing attention to the environment and ecology, and more demanding consumer demands, traditional industries, especially the metal materials industry represented by steel and non-ferrous metals, have been In pursuit of technological progress and equipment transformation. Continuous casting technology, as a widely used process in the production of steel and non-ferrous metal preforms, is particularly attractive. Although this process has been used in production for many years, compared with die casting, it has the advantages of cost savings, improved ingot quality, and easy use of automatic control technology. ^[2]

Continuous casting has been widely used at home and abroad, such as continuous

The concept of continuous casting of liquid metal was proposed as early as the mid-19th century. In 1840, Seller, in the United States applied for a patent for continuous ingot lead pipes. Besseme, 1846: Water-cooled, rotating twin-roller continuous casting machine produces tin, lead and glass plates. Subsequently, the concept of continuous casting of the mobile mold and the vertical continuous casting method of vertical casting were also successively proposed. In 1933, the pioneer of continuous casting, German Junghans, used a vertical continuous casting machine with a vibrating crystallizer to successfully cast copper and aluminum alloys. The continuous casting of nonferrous alloys was used in production as early as the 1930s. In the 1940s, Junghans built the first test continuous casting machine for pouring molten steel. At that time, research on technologies such as vibrating water-cooled crystallizers, immersion nozzles, and protective casting had laid the foundation for modern continuous casting machines. Subsequently, intermediate test continuous casters were built in the United States, Britain, Austria, Japan and other countries. In the 1950s, continuous casting technology was still in the industrial trial stage. In the 1960s, continuous casting entered the industrial application stage, and many continuous casting equipments came out one after another. In the 1970s, continuous casting technology developed rapidly under the pressure of energy shortage. In the 1980s, continuous casting technology became a mature technology and was widely used in the metallurgical industry. In the 1990s, continuous casting technology set off a new revolution. Many new continuous casting technologies were proposed one after another, and some of them were in the development and trial production stage.

During the early and mid-term development of continuous casting, the continuous improvement and maturity of continuous casting equipment and technology is inseparable from the emergence of many new technologies. The representative technologies are: (1) Tundish rapid replacement technology; (2) Multi-furnace continuous casting technology using a ladle turntable; (3) On-line mold width adjustment technology; (4) Multi-point bending and straightening technology (5) Crystallization liquid level control and steel leakage prediction technology; (6) Non-oxidizing pouring technology; (7) Compression pouring technology; (8) Light reduction technology; (9) Computer automatic control technology; (10) Gas -Water cooling, electromagnetic stirring applications, etc.

China started relatively early in continuous casting technology. In 1957, the first industrial test casting machine was designed and completed at Shanggang; at the end of the following year, the first productive vertical continuous casting machine was put into operation at the No. 3 Heavy Steel Plant. After the 1960s, the development and application of Chinese continuous casting technology set off a climax, which was prominently manifested in the development of arc continuous casting technology. However, before the 1980s, due to the lack of technical exchanges with foreign countries and the inability to learn from foreign advanced technologies in a timely and effective manner, the gap between China's continuous casting production technology level and foreign countries was widened. In the mid-to-late 1980s, the country attached great importance to the development of continuous casting technology. The first National Continuous Casting Working Conference was held in 1988, and for the first time, the production technology policy for continuous casting was put forward, and the strategic idea of vigorously developing continuous casting was clarified, which became a turning point in accelerating the development of continuous casting.

Since 1989, the growth of continuous casting slab output has become a major part of China's steel output growth. Since 1994, the growth of continuous casting slab output has exceeded the absolute growth of steel output, driving the rapid growth of China's steel output. The continuous casting ratio of China's steel industry reached 67% in 1998 ^[3]

Conventional continuous casting technology has completely replaced die casting in the steel manufacturing process and has become the dominant material production technology. In terms of total finished steel production, the continuous casting ratio of most countries in the world has exceeded 90%. After the 1990s, there have been some new trends in the development of continuous casting technology, which are mainly manifested in two aspects: first, the development and improvement of new continuous casting technology; second, the development of new materials based on continuous casting technology.

The development of continuous casting is an important means for structural optimization of China's metallurgical industry, which will fundamentally change the current situation of low efficiency and high consumption of metal materials production in China, and promote the development of product structure towards specialization. The development of advanced continuous casting technologies such as near-net-shape continuous casting, single crystal continuous casting, high-efficiency continuous casting, and hot casting and hot charging of continuous casting slabs will be very active, and it will drive the development of a series of new materials ^[1] .