The status quo and development countermeasures of casting technology (2)
Second, the problems in China's foundry industry
The technical level of China's foundry industry is about 20 years behind that of developed countries and cannot meet the needs of the rapid development of the national economy. The backwardness of technology, outdated equipment, high consumption of energy and raw materials, serious environmental pollution and poor working environment of workers have become the consensus of the industry.
Specifically in:
(1) Low process level and poor casting quality
1 castings have a large processing margin. Due to the lack of scientific design guidance, it is difficult for process designers to control the deformation problem based on experience. The machining allowance for casting is generally 1-3 times larger than that of foreign countries. The processing allowance is large, the energy consumption of the castings and the consumption of raw materials are serious, the processing cycle is long, and the production efficiency is low, which has become a bottleneck restricting the development of the industry.
2 Large casting segregation and inclusion defects are serious. After the solidification of large steel castings and large steel ingots, macroscopic segregation and coarse grain problems exist in the thick section of the riser and the casting.
3 The casting crack problem is serious.
4 The design of the gating system is unreasonable. Due to improper design, there are defects such as gas and inclusions, resulting in low casting yield and yield.
5 simulation software applications are not popular. Casting process simulation is a necessary part of casting production. In foreign countries, if there is no computer simulation technology, orders will not be available. China's foundry computer simulation started earlier. Although the core computing part has strong development capabilities, the overall software packaging capability is poor, resulting in mature commercial software development far behind developed countries. A considerable number of foundry companies are discouraged from computer simulation technology. lack of trust. Although this situation has improved, the companies that have purchased casting simulation software are still rare in their role, and they need to train software applications for their employees.
6 The production capacity of ordinary castings is excessive, the manufacture of high-precision castings is still difficult, and core technologies and key products are still dependent on imports.
(2) High energy consumption and raw material consumption
The energy consumption of China's foundry industry accounts for 25%-30% of the total energy consumption of the machinery industry, the average energy utilization rate is 17%, and the energy consumption is about twice that of developed countries. The energy consumption per ton of qualified cast iron produced in China is 550-700 kg of standard coal, and that of foreign countries is 300-400 kg of standard coal. The energy consumption per ton of qualified steel castings produced in China is 800-1000 kg of standard coal. 500-800 kg of standard coal. According to statistics, the input of materials and energy in the production process of castings accounts for about 55%-70% of the output value. The gross weight of Chinese castings is 10%-20% higher than that of foreign countries. The average production rate of steel castings is 55%, and foreign countries can reach 70%.
(3) Serious environmental pollution and poor working environment
In addition to a few large-scale enterprises such as FAW, Second Automobile, Daqi Dazhong, Shenyang Liming Company, such as sophisticated production equipment, advanced casting technology, and environmental protection measures, most foundry factories have outdated production equipment, backward technology, and rarely take environmental protection into consideration. problem. In the 1980s, the government made special adjustments to enterprises with small scale, low technical level and serious pollution, which increased the degree of intensification of enterprises, but the extensive characteristics of foundry production have not been fundamentally changed. More than 90% of foundry companies with poor production environment, poor operating conditions, backward technology and extensive production; the Environmental Protection Award was presented at the 63rd World Foundry Conference held in Hungary in 1998. None of the award-winning foundries in China This is extremely incompatible with China's status as a founding power. The environmental problems in China's foundry industry are also reflected in the excessive consumption of natural resources.
The charge in the casting production is mainly pig iron, scrap steel, coke, limestone, sand, core sand. Mainly used for transportation, sand mixing, molding, core making, baking, melting, pouring, cooling, falling sand, cleaning and post-treatment of raw sand, clay, coal powder, resin and other binders, curing agents, old sand, etc. The process is carried out in mechanical vibration and noise in terms of its operation content, and some work in high temperature, such as melting and pouring, and some produce irritating odor, and the dust working environment is even worse. In China's foundry, for every ton of castings produced, about 50 kilograms of dust is emitted. The smelting and pouring process discharges 200 kilograms of waste residue, 20 cubic meters of waste gas, and shapes and cleans waste sand by about 13-15 tons. With an annual output of 22 million tons of castings, the total amount of pollutants discharged each year is: 4.4 million tons of waste slag, nearly 16.5 million tons of waste sand, and 400 million cubic meters of waste gas. These data are sufficient to illustrate the seriousness of environmental problems in China's foundry industry. The use of high technology to achieve green casting is a key issue that needs to be addressed at present. (4) Talent shortage
The serious shortage of casting technical talents is the key to restricting the development of China's foundry technology. The main performances are as follows: 1 The number of technical and managerial personnel is small and unevenly distributed. The minimum factory technology and management only account for 12% of the total number of employees, and the largest number of factories account for 323%, a difference of 27 times. State-owned enterprises, especially military workers. The proportion of enterprises is high. 2 The number of senior talents is small. The technical management talents of foundry enterprises are mainly secondary, junior college and undergraduate students, especially the number of secondary and junior college students, and there are few graduate students. 3 New talent sources are difficult. Many colleges and universities no longer set up casting professions after the 1990s, and some large and medium-sized enterprises also have a downward trend in the schools, and the sources of new talents are increasingly difficult.
The fundamental reason for the lack of foundry talents is the low corporate treatment and poor working environment. 80% of the employees of state-owned enterprises are over 40 years old, and there are very few people aged 20-40. The professional and technical talents engaged in casting by private enterprises are mostly over 60 years old. Most of the workers are rarely professionally trained, and many are migrant workers engaged in foundry production. The technical level of the entire industry, especially the level of quality awareness and quality control, does not meet the requirements of market competition.
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