Casting is one of the most important methods of metal forming and it is the basis of thermal processing. The history of casting is as old as the history of the Chinese civilization. Our ancestors cast the exquisite bronzes of the “Sanxingdui†more than 4,000 years ago. The technical level is amazing, but in modern times, as the world's largest producer of castings, China The level of casting is behind the developed countries.
I. Overview of China's foundry industry
China's casting production has surpassed the United States since 2000 and has ranked first in the world for six consecutive years, including 22.42 million tons in 2004, an estimated 26 million tons in 2005, and an annual output value of more than 250 billion yuan. The output of castings accounts for the world's total output. As much as 1/4, it has become the world's foundry production base. According to the 2004 production statistics of the major casting producing countries in the world, it can be seen that the top ten casting producing countries can be divided into two categories. The first category is developing countries. Although the output is large, the added value of castings is low, there are many small enterprises, the number of employees is huge, and the proportion of ferrous metals is significant. The other is developed countries, such as Japan, the United States and Europe, which use high technology to produce high value-added castings.
In developed countries, casting technology is advanced, product quality is good, production efficiency is high, environmental pollution is small, and raw and auxiliary materials have been serialized. Europe has established a multinational service system, and its production is mechanized, automated and intelligent. The production process strictly enforces technical standards, and the casting scrap rate is about 2%-5%. Emphasis on using information technology to improve the design level of casting process, universal application software for filling solidification process simulation and process optimization design.
From the perspective of batch and labor productivity, Europe, the United States and Japan have great advantages. Japan's labor productivity is 140 tons of casting per capita per year, and China's estimated is about 20 tons, a difference of 7 times. China's labor cost is less than 1 US dollar / hour, which is several times different from that of developed countries, so export castings have advantages. However, in recent years, the price of materials has soared, making the advantages of China's export castings in terms of material costs disappear. In terms of product quality and grade, we lag far behind developed countries. In recent years, although China's casting exports have increased, exports account for only 97% of China's total output, accounting for less than 8% of the world's castings market. The overall growth rate is slow, showing poor quality and low prices. For a long time, the exported castings are mainly medium and low-grade products, and all kinds of pipe fittings, radiators, kitchen utensils and bathing utensils accounted for 36%. Although some export castings can meet international standards, there is still a distance to meet European and American customer standards.
In China, the foundry industry is an important industry related to the national economy and the people's livelihood. It is the foundation of the pillar industries such as automobile, petrochemical, steel, electric power, shipbuilding, textile and equipment manufacturing, and is an important part of the manufacturing industry. In mechanical equipment, castings account for a high proportion of the weight of the whole machine, 80% of internal combustion engines, 50%-80% of tractors, and 50%-60% of hydraulic parts and pumps. Almost all the key components in the automobile are cast; major equipment such as metallurgy, mines and power stations are dependent on large castings and forgings, and the quality of the castings directly affects the quality and performance of the machine.
China's foundry production enterprises are mainly distributed in the east, with less production in the west. At present, there are about 24,000 foundry companies and more than 1.2 million employees. From the perspective of industrial structure, there are casting factories or workshops that are subordinate to the main production plants, professional foundries, and a large number of township foundries. In terms of scale and level, there are large-scale foundries with advanced technology, high degree of mechanization and annual output of tens of thousands of tons of castings, such as some advanced foundries in the heavy industry, automobile industry and aviation industry, as well as backward technology and poor equipment. Hand-operated, small-scale foundry with an annual output of more than 100 tons of castings.
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