Research status of gray cast iron at home and abroad

In order to improve the properties of gray cast iron and deeply develop the application of gray cast iron, many countries have carried out a lot of research work. AFS established a special thin-walled cast iron group (twig) in 1997 to improve the technical development and application of high-strength castings and thin-walled parts; During the Seventh Five Year Plan period, China listed the technology of high-strength thin-walled gray cast iron as the main key project, carried out a lot of research and achieved fruitful results. A large number of studies and tests show that the primary task of developing high-strength thin-walled gray cast iron is to develop gray cast iron with high carbon content, high strength, high stiffness and low stress and its strengthening process.

Machinery industry, automobile manufacturing industry and construction industry are the main pillar industries in China, which provides a very good development opportunity for the foundry industry. However, China’s casting industry has been facing problems such as poor economic benefits, low casting product quality, poor basic conditions such as casting production technology and process technology equipment, high energy consumption, poor labor conditions, environmental pollution and so on. Therefore, the development of high-quality and high-tech castings has become the primary task of the development of China’s foundry industry. With the popularization of automobile lightweight, cast iron lightweight will inject new vitality into cast iron industry. Therefore, the research and popularization of production technology of high-strength thin-walled gray iron castings has become the key to the problem. At present, the new technologies and hot spots in the research and production of gray cast iron in the world mainly include: (1) microstructure strengthening of high carbon equivalent gray cast iron; (2) Production technology of thin-walled high-strength gray iron castings, including manufacturing of engine cylinder block and cylinder head, inoculation treatment technology of thin-walled high-strength gray iron, etc; (3) The application of advanced manufacturing technology in the production of gray cast iron, including laser strengthening treatment of the surface layer of gray cast iron, the application of artificial intelligence technology in the performance prediction of gray cast iron, and the semi-solid die casting technology of gray cast iron.

So far, the main material of commonly used large mechanical products, such as cylinder block and cylinder head of high-power diesel engine, is still gray cast iron. In recent years, foreign countries began to test the production of engine cylinder block and cylinder head with vermicular cast iron. However, the production process of vermicular cast iron is unstable, and there is a certain gap in cost compared with gray cast iron. Therefore, the development of vermicular iron cylinder block and cylinder head still has certain limitations. Therefore, people began to further explore the properties of gray cast iron. How to produce gray cast iron castings with high strength, good mechanical properties and high service life, and expand its application range, has attracted great attention of the majority of scientific researchers and manufacturers.