Casting technology

1) the low level of technology, the quality is poor
(1) casting machining allowance. Because of the lack of scientific guidance design, process design personnel on experience is difficult to control the deformation problem, casting machining allowance in general 1 to 3 times larger than abroad. Machining allowance is big, the energy consumption of the castings and raw material consumption, processing cycle is long, the production efficiency is low, has become the bottleneck which restrict the development of the industry.
(2) large casting defect serious segregation and inclusions. After the large steel castings and large steel ingot solidification, the riser root exists, casting of heavy section macro segregation, coarse grains.
(3) of the casting crack problem is serious.
(4) gating system design is not reasonable. Due to the improper design, such as volume gas and inclusion defects, lead to casting production rate and qualified rate is low.
(5) simulation software application is not widespread. Casting process simulation is a necessary link in casting production, in a foreign country, if there is no computer simulation technology, it can't get the order. Computer simulation of casting industry in China started relatively early, while the core computing part development ability is stronger, but the overall software package ability is poor, lead to the commercialization of the mature software development is far behind the developed countries, quite a number of foundry enterprises of computer simulation technology, the lack of trust. The situation is better, but on the casting simulation software in the enterprise, also can play the role of rare, be badly in need of software application training for the employees of the enterprise.
6 common casting of excess production capacity, high precision casting manufacturing is still difficult, core technology and key products still rely on imports.
2) high energy consumption and material consumption
China's foundry industry energy consumption accounted for 25% - 25% of total energy consumption of mechanical industry, energy utilization rate is 17% on average, energy consumption is approximately twice the casting in the developed world. Qualified castings per production 1 ton of energy consumption in China for 550-700 kilograms of standard coal, abroad for 300-400 kilograms of standard coal, the energy consumption of the production 1 ton per qualified steel for 800-1000 kilograms of standard coal, abroad for 500-800 kilograms of standard coal. According to statistics, material and energy in the process of casting production output value accounts for about 55%, 70%. Gross weight 10% - 10% higher than average abroad Chinese castings, steel casting process product rate is 55% on average, foreign can reach 70%.
3) conditions, severe pollution
In addition to a few large enterprises in China such as faw, no.2, big big heavy, shenyang liming company production equipments, advanced casting technology, such as environmental protection measures in place, the basic point most foundry production obsolete equipment, backward technology, general rarely consider environmental protection issue. In the 1980 s, the government of small scale, low technical level and polluting enterprises have adjusted their specialization, raised the intensive degree of the enterprise, but the rough characteristics of casting production have no fundamental change. Production site conditions, poor operation condition, backward technology, extensive production foundry enterprises accounted for more than 90%; In Hungary in 1998 at the 63th annual conference of casting and the environmental protection award, none of the award-winning foundry in China, the commensurate with China foundry superpower status. Environmental problems of the foundry industry of our country in excessive consumption of natural resources.
Casting furnace charge is mainly in the production of pig iron, scrap steel, coke, limestone, sand and core sand, etc. Mainly is the original sand, clay, coal powder, resin binder, curing agent, such as transportation, sand, sand molding, core making, baking, melting, pouring, cooling, shakeout, cleaning, pretreatment and post-treatment in terms of its job content is in mechanical vibration and noise, some still in the high temperature? Such as melting, pouring in the homework, some produce excitant odour, dust in the working environment is bad. 1 ton casting foundry every production in China, about 50 kilograms of dust, melting and pouring process emissions waste residue 200 kg, 20 cubic meters, modelling and clean up the waste sand about 13-15 tons. In annual output of 22 million tons of castings, annual emission amount is: 4.4 million tons of waste residue, waste gas, sand nearly 16.5 million tons, 400 million cubic meters. These data are enough to explain the severity of the problem China's foundry industry environment, use high technology to realize green casting is the key to solve the need to focus on the current problems.