Development trend of sand forming technology
Tide mold modeling through manual compacting → shock + compaction compacting → high pressure + micro shock compacting → air punching compacting → static compaction compacting several development stages. The essence of hydrostatic molding technology is “air-punching precompaction + compaction”. It has the following advantages: clear outline of the mold, high and uniform surface hardness, small slope of the mold, high utilization rate of the mold plate, low wear of the process equipment, high surface finish of the mold, low waste rate of the mold. Therefore, it is the latest and most advanced molding process, and has become the mainstream compacting process today.
Near net shape technology development trend
Casting and molding process
Vanishing mold casting, also known as vaporized mold casting, solid casting, cavity casting, is known in the foundry industry as the “21st century casting technology”, “casting of green engineering”. The method of this process is to use binder-free dry sand and vacuum technology.
Investment casting molding process
The investment mold precision casting process has water glass shell process, composite shell process, silica gel shell process. Automotive product materials are carbon steel, alloy steel, non-ferrous alloys and ductile iron. Foreign high-alloy steel, super-alloy materials. Melting equipment domestic use of ordinary, fast medium frequency furnace; foreign use of vacuum furnace, flip furnace, high frequency furnace technology. The future development trend of investment casting technology molding process is the product is closer and closer to the commodity, the traditional fine casting only as a blank, has not adapted to the rapid strain of the market; the complexity of the product and quality grade is getting higher and higher; R & D means more and more powerful, professional collaboration began to appear, CAD, CAM, CAE application to become the main technology for product development.
The development trend of core-making technology
At present, domestic and foreign automotive casting core making three kinds of core making process, in modern automotive casting often used in parallel with the main process are hot core box core making, shell core core making, cold core box core making, etc., the traditional fat or oil sand core making has been eliminated.
The development trend of cast iron melting technology
At present, domestic and foreign cast iron melting technology has two main ways: one is the use of large hot air dust cupola and industrial frequency insulation furnace duplex melting process; the second is the use of medium frequency induction furnace melting process technology.
Alloy cylinder block, cylinder head die-casting molding technology
Aluminum alloy is the fastest and most widely used light metal on the car, because the performance of aluminum alloy itself has reached the quality of light, high strength, corrosion resistance requirements. Initially, aluminum alloy is only used for some non-impact parts. Later, by strengthening the alloy elements, the strength of aluminum alloy is greatly improved, because of the light weight, good heat dissipation and other characteristics, can meet the engine piston, cylinder block, cylinder head in the harsh environment work requirements. Aluminum alloy cylinder block, cylinder head die-casting forming core technology can improve the purification, refining, refinement, densification and other material quality control, so that the quality of aluminum castings to achieve consistency and stability.
Semi-solid die-casting molding technology
Semi-solid technology originated in the United States, so in the United States this technology has been basically mature, in the global leading position, is called the most promising material forming and processing technology in the 21st century.
The development trend of cast iron material
Technology of thin-walled high-strength gray cast iron parts
Gray cast iron parts are used in large quantities in automobiles, due to the low cost and good casting performance advantages of this material. With the light weight requirements of automotive technology, the growth and development of gray cast iron will be affected to a certain extent, so strengthen the development and application of thin-walled high-strength cylinder block and cylinder head casting technology will be the development trend.
Creeping graphite cast iron technology
Ductile iron has the strength of ductile iron, compared with gray cast iron and similar anti-vibration, thermal conductivity and casting performance, good plasticity and heat resistance fatigue performance, can solve the problem of thermal fatigue cracking of high horsepower cylinder head. Perforated graphite cast iron is widely used in the huge potential market is in the automotive industry, its main product is the engine cylinder block and high-power diesel engine cylinder head castings. With the light weight and power (kW / displacement) of the car, the cylinder block and cylinder head working temperature is getting higher and higher, many parts of the working temperature of more than 200 ℃, at this temperature, the strength of the aluminum alloy is significantly reduced, and creep iron has a great advantage.
Ductile iron technology
Ductile iron due to its high strength, high toughness and low price, so there is still a lot of development in the automotive market. The automotive casting industry ductile iron mainly has 4 products technology process development trend. First, cast pearlite, high-strength truck and car crankshaft, cast ferrite, high elongation of the car exhaust and axle housing chassis class castings; second, security class castings, cast production of cars steering knuckles; third, heat-resistant ductile iron parts, high silicon-molybdenum, silicon-molybdenum, high nickel ductile iron, the material production of exhaust parts; fourth, Aubert ductile iron, mainly for the production of crankshafts and other products. In addition to the above, the automotive foundry has produced cast ductile iron cold-excited camshaft.
Casting process computer application technology development trend
With the rapid development of automotive casting technology, in order to shorten the production preparation cycle of castings and reduce the risk of new product development, the use of rapid prototyping technology, computer simulation, three-dimensional modeling, CNC technology is increasingly widely used. Rapid prototyping technology applications to develop new products for prototype and melt casting wax mold, but also to make phenolic resin shell type, shell core, can be directly used to assemble into sand. Simulation modeling process is becoming one of the frontier areas of international automotive casting concern. Application of Magma, China Casting software for new product casting filling, solidification of the temperature field and flow field simulation analysis processing, prediction and analysis of casting defects.
Casting inspection technology
The application of non-destructive testing technology is becoming more and more widespread. Fluorescent magnetic powder is often used to detect surface cracks for important parts; ultrasonic or audio is used to detect the spheroidization rate of ductile iron; eddy current detects the matrix organization of the casting (pearlite content). In order to meet the requirements of the important parts detection, some of the above three testing instruments combined into an automatic detection line.
Green casting technology development trend
“Green casting” is to make casting products from design, manufacturing, packaging, transportation, use to end-of-life treatment of the entire product life cycle, the minimum negative impact on the environment, the highest resource efficiency. Foundry industry has traditionally been considered a high energy consumption, high pollution industry, to continuously develop new energy-saving, clean, low emissions, low pollution casting materials to be used in production.
