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Overview of Foundry Technology Roadmap

Sources:本站 | Release date: 2017-10-19 | Browsing volume:
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First, the development of casting technology status and trends
(I. Overview
Casting is the technology of solidifying and forming metal castings after liquid metal is injected into the cavity. It is widely used in the pillar industries of aviation, aerospace, automobile, petrochemical, metallurgy, electric power, shipbuilding, textile and so on, and is the main method for obtaining the rough parts and components of mechanical products one.
Castings in aero-engines, rocket engines, gas turbines, automobile engines, rail transportation and other types of equipment occupy a large proportion, to improve the performance of the host equipment is essential, casting forming is the basic manufacturing process machinery industry. Since 2000, China has occupied the first place in world casting production for 16 consecutive years. It is the world's founding power and has made a positive contribution to the national economic development of our country. However, China still lags behind in some high-end casting foundry technologies, causing China's high-end equipment Development lags behind. In the foundry industry, a large number of small and medium-sized foundry companies are experiencing extensive management and poor production capacity, which cause damage to the ecological environment in our country. Therefore, more investment is needed in energy consumption control and environmental protection.
In recent thirty years, great changes have taken place in casting technology in the world. The continuous development and integration of mechanization, automation, digitalization and intelligent technology have made human beings increasingly demanding for a sustainable development environment, which has contributed to the world's foundry Technical progress. The next 15 years are the period of structural adjustment and strategic period for the development of foundry industry in China. It is an industry consensus to develop "high quality, high efficiency, smart and green" foundry technology.
At present, the development goal of foundry technology in our country is to greatly improve the innovation capability of independent design and manufacture of high-end foundries required for the development of equipment manufacturing industry in China. In the field of advanced foundry technology, casting forming technology of extra large and key components of major projects, Foundry technology and green foundry technology to form a batch of world-class innovations and provide strong technical support for the equipment manufacturing of important sectors of our national economy so that our country will develop from a world-foundry country to a world-foundry power.
(B) the status quo
Foundry technology includes casting materials, casting forming methods, casting equipment and testing and environmental protection and safety and so on. The development of foundry technology is closely linked with the development of national economy and the global environment for economic development. After many years of rapid development of China's foundry industry, Since then, the growth rate of the global manufacturing environment has slowed in recent years and is now at a critical period of structural adjustment and upgrading.
Released from the statistical data released by agencies can be insight into the development of foundry industry and foundry technology in China in recent years. At present, there are about 26,000 foundry sites in China, each producing 1,777 tons of castings per year, much lower than Germany (8,818 tons), ranking the first among the top 10 countries in terms of castings production output. Many economies Smaller foundry businesses have been sluggish in technological advances and equipment upgrades. According to the data released by China Foundry Association in May 2016, the total output of various types of castings in China in 2015 was 45.6 million tons, down 1.30% from 2014, the first negative growth after many years of continuous growth since 1999. Aluminum alloy castings increased by 4.27% and ductile iron castings by 1.61% in 2015, of which aluminum / magnesium alloy castings accounted for 13.4% (2014: 12.7%) and ductile iron / gray castings = 1: 1.60 (1 in 2014 : 1.68), indicating that China's higher value-added castings production increased slightly. According to statistics of goods classified as molded products in the import and export data of the Customs (with the import and export of parts and assembly products can not be separated from the imported and exported goods of the Customs), the export volume of various types of castings in China in 2015 was 1,944,300 tons, The price is 1 484 US dollars / ton, various types of castings imported 17,400 tons, the average import price of 7 214 US dollars / ton, indicating that a small part of China's high value-added castings still need to be imported.
Over the years, with the support of science and technology projects at all levels of government, the cooperation in production, education and research, the gradual narrowing of the gap between the domestic foundry technology and the foreign foundry technology, the progress has been made in technological upgrading and admission auditing in the structural adjustment of the industry and the matching with host equipment manufacturing facilities Breakthroughs have been made, outstanding international competitiveness of casting enterprises continues to increase and many other aspects. For example, light alloy and superalloy precision casting forming technology to meet the development of a variety of new advanced defense equipment requirements; large heat-resistant corrosion-resistant stainless steel materials and casting forming technology to meet the development of China's new generation of power generation equipment parts manufacturing needs; large The development of ingot macrosegregation and shrinkage control technology has improved the internal quality of the billets used in the large forgings of mechanical equipment in our country. The breakthrough in research and development of a new type of high temperature titanium alloy containing Nb has made a breakthrough. The development of automotive casting casting technology has not only driven the large- Mechanization, automation, digital and advanced casting technology continues to improve the level of application, but also for the development of China's automobile industry has made a significant contribution to the casting process simulation and application of numerical simulation technology to improve the level of foundry design, advanced digital casting Technology in a number of outstanding foundry enterprises have been effectively used.
Although casting technology in China has made remarkable progress in recent thirty years and has played an important role in the development of the national economy and national defense, it should be soberly realized that the situation of large and not strong foundry industry in our country has not fundamentally changed. Casting There are differences between large and small in developed countries with different technical directions in the field and with different reasons, which are summarized as follows.

Casting black metal and forming
Cast iron, high-performance ductile iron casting technology is not stable, not reliable, the key mechanical properties of less than the level of developed countries. Large cross-section ductile iron casting technology, but off, one hundred tons of large-scale spent fuel storage containers can not be manufactured independently. Machine bed castings poor dimensional stability, resulting in poor retention of high-end CNC machine tools poor quality, leading to long-term dependence on imports of high-end CNC machine tools.
Casting, China's offshore equipment with seawater corrosion resistant duplex stainless steel material system is not complete, foundry engineering application of the lack of basic data, casting forming some of the mechanism of the problem is not clear. Domestic large alloy ingot casting process of internal defect control technology and service conditions under extreme working conditions still need to tackle key problems. Domestic high-end casting capacity shortage of steel enterprises, the new power generation equipment with large high-end castings casting technology lags behind developed countries in Europe, some large-scale stainless steel castings used in nuclear power equipment and new thermal power equipment with high temperature castings rely on imports, individual products monopolized by foreign countries, casting Low-end steel companies overcapacity. Electroslag casting technology and engineering application of large and complex shaped shaped workpiece needs to be expanded.
Casting wear-resistant materials, China's steel wear-resistant material system developed and the gap between developed countries is not obvious, the newly introduced cast wear-resistant materials, national standards and international standards. However, some high manganese steel casting business casting technical indicators do not meet the national standard requirements and requirements, casting technology and casting quality lags behind the level of developed countries in the world. In the production process of domestic foundry wear-resistant materials, the application of advanced liquid steel smelting and refining and filtration technologies lags behind and the development and modification of steel liquid furnace with Chinese characteristics still need to be developed. Advanced sand casting technology and special casting technology for casting wear-resistant materials can significantly improve the service life of wear-resistant materials to be further developed and popularized. The development of casting wear-resistant materials heat treatment technology to improve the wear-resistant castings hardness, toughness and service life, reduce the amount of alloying elements, to prevent cracking of thick wear-resistant parts and decarbonization of wear-resistant steel parts is also the direction of efforts.

2 modeling materials
For modeling materials, furan resin binders produced by most domestic manufacturers have high toxicity, poor high-temperature concession, unstable performance and severe tendency of hot cracking when used in steel casting, and are used for carburizing seepage on the surface of castings when casting mild steel Sulfur and other issues, foreign countries have adopted environmentally friendly biomass furan resin, with toxicity, strength, hardening speed, low cost advantages. The domestic application of small proportion of hard sand, wet sand accounted for a large proportion of large-scale use of toxic and large-scale use of wet powder sand, foreign mainly ester-based alkaline phenolic resin sand or environmentally friendly furan resin from hard sand, casting surface quality Good and good working environment. Domestic cold box core making process there is solvent toxicity and sticky mold serious problem. A single species of domestic paint, large pollution, high cost, backward brushing process, small batch of paint mixing and low degree of automation, quality is not stable. Recycling of old sand domestic recycling rate of 30% to 60%, many small foundries all the old sand emissions, the regeneration of foreign old sand recycling rate of up to 80% to 90%. In Europe, some countries have succeeded in using low-cost environmentally-friendly inorganic binder sand for mass production of complex high-end precision thin-wall precision castings and have just begun to explore the experiment in China.
3. Cast non-ferrous alloy and metal matrix composites
Casting superalloy, the third generation of single crystal superalloy has been developed in aero-engine complex single-crystal blade access to applications, batch products pass rate of 80% or more, the fourth and fifth generation of single crystal materials are pre-research. Foreign mainstream mainstream gas turbines on the first and second stage turbine blades have also been widely used columnar / single crystal superalloys. At present, China has a production capacity of complex single-crystal blades for small-batch aeroengines, but the passing rate of the products is less than 60%. The third-generation single-crystal blade casting technology of aeroengines is in the pre-research stage. Large cylindrical / single crystal blades for gas turbines are in Laboratory research phase.
In the aspect of casting aluminum alloy, the innovation abilities of domestic aluminum alloy melt refining technology are poor; the basic theory of new type foundry aluminum alloy is more and less than that of engineering application; the new technology of aluminum alloy casting lacks systematic comprehensive research and development, including alloy series, equipment , Control, software and hardware development, and more with foreign disparities.
Cast magnesium alloy, China has developed a variety of high-performance rare earth magnesium alloy materials. Aerospace high temperature heat-resistant Mg-Gd-Y-Zr magnesium alloy material has reached the international advanced level in performance, but in the large complex high strength heat-resistant cast magnesium alloy casting solidification theory and forming process far behind the developed countries. So far, only the United States and the former Soviet Union have magnesia-lithium alloy grades in the world, and the domestic research on magnesia-lithium alloys is still very limited. In particular, there is a lack of research on ultra-light cast magnesium-lithium alloys, Aerospace and electronics industries in areas such as the huge application of disproportionate prospects.
In the field of casting titanium alloy, high temperature titanium alloy based on titanium-aluminum compound has been mass-produced and applied in the United States. Domestic high-Nb-Ti-Al alloy has also begun to be applied. Recently developed Ti-45Al-8Nb single crystal alloy, The ability to increase the temperature of 150 ~ 250 ℃ above, better than similar alloys in the world, made a major breakthrough. However, the domestic research and production of high temperature titanium alloy has not yet got rid of the dependence on foreign key melting equipment. China started late in the direction of low-temperature titanium alloy technology, mainly to follow the current imitation and a breakthrough.
Casting copper alloy, copper alloy material technology research and development is not systematic imperfections, resulting in marine copper alloy pressure pump valve castings internal quality is unstable, low yield. The world's large marine propeller manufacturing technology is relatively confidential, our country has mastered the manufacturing technology of super-large marine copper alloy propeller, but casting chemical composition control technology, corrosion resistance, etc. have great room for improvement.
In the aspect of casting metal matrix composites, in order to reduce the manufacturing cost of metal matrix composites and meet the needs of the civil society, the research focus has shifted from the 1980s to particle-reinforced particles, whiskers, short fibers reinforced discontinuous reinforced metal matrix composites . At present, the metal matrix composites prepared by the liquid casting method occupy half of the country and have been used in large quantities in foreign countries. However, there are more basic research in China and less engineering applications. There are two common problems in the preparation of metal matrix composites. One is how to achieve the uniform distribution of reinforcements in the alloy matrix, and the other is how to achieve a good bond between the reinforcements and the matrix metal interface. Therefore, the preparation technique is metal matrix The bottleneck of the development of composite materials. The comprehensive performance of aluminum-based composite materials still need to continue to improve, and to achieve the design of materials and stable manufacturing, in order to reduce manufacturing costs and speed up the industrialization process. Magnesium matrix composites in the preparation, casting forming processing technology is still not mature, the application is still limited. Copper-based composite materials manufacturing process is still relatively complex, the performance also failed to meet the high cost of production. Titanium-based composites combine the ductility and toughness of titanium with the high-strength and high-modulus ceramics to achieve higher shear and compressive strength and better high-temperature mechanical properties, replacing them in some areas The traditional titanium alloy materials, currently at the forefront of application, optimize the technology and reduce costs will become an important factor in the stable application of the material market.

4 special casting forming method
Investment Casting, the United States, Britain and other developed countries in investment casting industry, applied to aerospace, industrial gas turbines, military and other fields of high value-added high temperature alloys, titanium, aluminum and other castings accounted for more than 70% China's high value-added investment castings castings accounted for less than 30%. China's aero-engine and ground gas turbine high-temperature alloy column crystal / single crystal turbine blade directional solidification casting forming technology behind the western developed countries 10 to 20 years, high-performance industrialized directional solidification equipment mainly relies on imports. Near-net-shape technology for large, thin-walled, complex investment castings is challenged with process equipment, quality control methods for the interior and exterior of castings, and high-stability shell coating systems. The process stability of the titanium alloy investment casting surface layer shell system still needs improvement. The new large-capacity titanium alloy smelting equipment is to be developed. Investment casting with a complex ceramic core forming, ceramic core removal process and equipment need in-depth study and solution.
High-pressure casting, the automotive structure with die-casting aluminum, magnesium alloy basically rely on imports, die-casting aluminum, magnesium alloy recycling technology behind. Foreign high-vacuum die-casting can be followed by heat treatment and welding, the domestic high-vacuum die-casting technology and equipment are immature, there are still holes in the casting defects, high vacuum die-casting heat treatment and welding technology is in the exploratory stage. Foreign countries have developed suitable for complex hole or cavity shape parts die-casting soluble core material, and die-casting technology for soluble core preparation, soluble core material and preparation technology research and development and industrial applications are in the initial stage, the domestic No related technology has been developed yet. Developed countries have carried out intelligent die-casting technology with sensor research and development and application system development, and in recent years established for the analysis of process parameters of expert systems and process parameters for the intelligent control system adjustment, the domestic die-casting process sensor research and development and technology Parameter monitoring applications have been developed, but the development of expert systems and intelligent control systems is still blank.
Anti-gravity casting, China's high-quality thin-walled complex casting low-pressure casting forming technology and high-efficiency casting technology behind the developed countries. The domestic low-cost advanced low-pressure casting technology and equipment for the casting of high-quality complex copper alloy valve castings are lacking. Domestic for high temperature alloys, titanium and other high temperature easy oxidation alloy material anti-gravity casting technology or composite anti-gravity casting technology and equipment in the exploration stage, foreign large-scale engineering applications. Differential pressure casting, pressure casting and vacuum suction casting technology application of basic research less, did not reach the level of a large number of foreign applications. Domestic anti-gravity casting equipment to achieve the ability of the process, efficiency and control accuracy still need to be improved.
Squeeze casting, the largest foreign casting size reached 1200 mm × 400 mm × 300 mm, forming castings weighing 50 kg, the largest casting forming


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