China: Henan Gong county in Western Han Tiesheng ditch, late iron sites unearthed iron through metallographic examination. Having radial spherical graphite. Ball rate is equivalent to a level of modern standards. And modern ductile iron is only in late 1947 successfully developed abroad. Ancient cast iron in China. In a fairly long period silicon content is low. That is. In the Western Han Dynasty about 2,000 years ago. Spheroidal graphite iron in our country. It has been obtained from pig iron casting silicon by low softening annealing method. This is a major achievement of ancient cast iron technology. Is a miracle in the world history of metallurgy.
Ductile iron manhole for its excellent performance. In use can sometimes replace the expensive cast steel and forged steel. Widely used in machinery manufacturing industry. International metallurgical industry in the past has been that ductile iron is a British invented in 1947. Some Western scholars have even claimed. No modern technology. Ductile invention is unthinkable. In 1981, China's iron ball expert use of modern scientific methods. For unearthed 513 ancient Han Wei and iron were studied. Through a lot of data to determine the Han Dynasty appeared spheroidal graphite cast iron. The research is presented at the 18th World Congress on the History of Science and Technology. Stir international community and the history of science casting industry. International experts in metallurgy history after 1987, verify this thought. Ancient Chinese have felt for manufacturing ductile cast iron soften operation of law. This is the history of the world for restaging metallurgy program on behalf of great significance.
Abroad: 1947 British H.Morrogh found. Additional cerium in hypereutectic gray cast iron. So that when the content is above 0.02wt% spherical graphite. 1948 United States A.P.Ganganebin et al point out. Adding magnesium in cast iron. Then bred with ferrosilicon. When residual magnesium is greater than 0.04wt% when. To obtain a spherical graphite. Since then, ductile iron began a large-scale industrial production. Ductile iron as the pace of development of new engineering materials is amazing. 1949 World ductile iron production was only 50,000 tons. In 1960 was 53.5 million tons. 1970 grew to 500 million tons. 1980, 760 million tons. In 1990 to reach 9.15 million tons. In 2000 to reach 15 million tons. Ductile iron production growth rate in industrialized countries particularly fast. 75% of the world production of ductile iron by the United States, Japan, Germany, Italy, Britain, France, the six countries of production. China ductile iron production started early. 1950 successfully developed and put into production. China's annual production of 2.3 million tons of ductile iron, in the United States, after Japan, ranking third in the world. Development of the rare earth magnesium ball agent suitable for China's success. Austenitic ductile iron and cast - production technology and research bainite ductile iron, and other fields have reached a high technical level.
(1). Pearlite cast ductile iron crankshaft and cast ferritic ductile iron automobile chassis parts, respectively, of the second car factory in Nanjing Automobile Factory and the first automobile plant put into operation. This indicates that China cast ductile iron production reached a high level. With suitable kits for desulfurization, double melting method, instantaneous breeding, breeding technology block and the audio detection and thermal analysis using fast analysis technology. China marks the large number of water production technology with the international advanced level automotive castings gap is narrowing.
(2). Experimental study of the large cross section (wall thickness greater than 120mm) ductile iron metallurgical factors and the corresponding measures of the production process. With the right amount of ytirium composite ball agent, forced cooling, solidification, delayed breeding. If necessary, add a small amount of antimony, bismuth prevents graphite iron castings central portion distortion and loose tissue and the like. We have been successfully produced 38 tons of large and complex structures. 17.5 tons of diesel heavy body section is 805mm ductile iron rolls and the like.
(3). Research and Application of Bainite Ductile Iron - austenite. 70's and early 20 century. Almost at the same time China, the United States, Finland three countries announced the successful research austenite has high strength, high toughness - bainitic ductile iron (collectively, the international ADI). This material tensile strength up to 1000MPa. Therefore, it is widely used in gear, and various structural parts, as compared with steel, Austria - Tony ductile iron has significant economic and social benefits.
(4). Ductile iron pipe and horizontal continuous casting ductile iron profiles. China has successively built several ductile iron pipe plant. And in recent years, there will be several ductile iron pipe plant built. In 2000, China centrifugal casting ductile iron pipe with an annual output of 90 million tons. In addition, China's self-developed horizontal continuous casting ductile iron production line profiles have been identified by the State. And there are many companies put into operation. Coupled with China imported a production line. By 2002, China's annual output capacity ductile iron profiles up to several tons.
(5). Systematic determination of rare earth magnesium ductile iron mechanical properties and other properties. Providing designers with the relevant data. Determination of the physical properties of rare earth magnesium ductile iron proportion, thermal, electromagnetic and so on. Study on the graphite substrate and the influence of the organization on the ductile properties of metallographic standards. Systematically measured ferritic ductile at room temperature, low temperature, static and dynamic conditions of the various properties. In addition, the study of stress-strain properties of rare earth magnesium ductile iron, small energy repeated impact resistance and fracture toughness. And began to be used to guide production. Combined with the application of ductile iron gears. Also systematically studied the bending fatigue strength and contact fatigue strength ductile iron. And ductile iron gear pitting, spalling mechanism and so on. (6) rare earth magnesium ductile iron. In terms of high-strength low alloy ductile iron. In addition to copper, molybdenum more research, but also nickel, niobium were studied. In the use of natural pig iron production of vanadium and titanium-vanadium alloy ductile aspect. Some units in China a lot, the system work. Although manganese nodular cast iron is not stable enough in performance. In the system of research and production applications. It has achieved remarkable economic benefits.
