"GGG40 cast ball ink casting performance test research and production test"
Release time:
2012-09-28 15:04
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In the 1980 s, all kinds of casting research institutes and schools all over the country organized casting experts to devote themselves to the research and experimental research of cast high toughness ferrite ductile iron. At that time, the newly established China Heavy Duty Truck Group Company imported more than 85% of the castings of Austrian STEYR heavy duty vehicles from Germany standard DINGGG40 ductile iron (equivalent to the new national standards GB and QT400-15). In order to localize STEYR heavy duty vehicles, China Heavy Duty Truck Group Company gave Shaanxi Heavy Duty Truck the scientific research task of jointly developing and producing cast GGG40 in cooperation with Xi 'an Jiaotong University. At that time, Shaanxi Heavy Duty Truck Foundry plant undertook the task. Under the conditions of the 1980 s, the quality of raw materials (pig iron, scrap steel, etc.) was poor (S, P, Mn and trace elements were high), spheroidizing agent and inoculant were relatively single, and the choice was limited. Some of them had to be self-made and self-made. After three and a half years, through the joint efforts of all colleagues in the scientific research team, the scientific research task of "GGG40 cast ductile iron performance test and production test" has been fully completed. In May 1989, an appraisal committee composed of well-known experts, professors and foundry colleagues from the factory hired by China National Heavy Duty Truck Group Corporation conducted production appraisal and acceptance at the site of Shaanxi Heavy Duty Truck Foundry Branch, and unanimously determined: "This achievement has reached the international level of similar materials., It is in a leading position in China."
After a lapse of more than 30 years, a careful reading of the research results and the results of the 90-year "Foundry" magazine experimental research column published papers on the current production of QT400-18AL, QT350-22AL wind power low temperature resistance high plastic toughness cast ductile iron castings still have a good guiding role. For example: ① the influence of trace elements in the furnace charge was studied in the current year, and the inflection point of the straight-line decrease of plastic toughness (δ%, ak) when the total amount of trace elements Σ T = 0.15 was found; ② the effects and influences of the five elements c, Si, Mn, p and s were studied in depth; ③ on the basis of practice, a small dose was clearly proposed for the production of cast ductile iron, multiple inoculation (pre-furnace discharge inoculation, inverted bag inoculation, pouring flow inoculation or type inoculation block inoculation) can maintain saturated inoculation state from beginning to end under the condition of little silicon increase: (for improving nodulizer level to reach level 1~2, refining graphite balls, the number of graphite balls reaches more than 200/㎜ 2, the size and distribution of graphite balls are uniform, ferrite F>95%),④ The implementation of molten iron filtration technology to improve the purity of molten iron and other measures, so that the comprehensive performance of cast ductile iron reaches: δb ≥ 420 N/㎜ 2,δ17~26.5,-60 ℃, δ>15%
Impact value of smooth specimen ak 70~140 S/cm2
Impact value of U-notch specimen ak 20~25 S/cm2
The normal and low temperature impact values of V-notch specimens are equivalent to those of ISO and QT400-18AL.
This achievement won the first prize of scientific and technological achievements of heavy truck Group Corporation in 1990, and the third prize of scientific and technological progress of China Automobile Industry Corporation in December of the same year. In 1992, he was awarded the "National Science and Technology Achievement Certificate" issued by the National Science and Technology Commission of the People's Republic of China.
This achievement has been selected in "China's Eighth Five-Year Plan" Science and Technology Achievements Selection "," China's Practical Science and Technology Achievements Dictionary "," World Excellent Patent Technology Selection (China Volume) 1996 "," 21st Century Talent Pool 1 "and won" The Honorary Certificate of Selected in the 21st Century Talent Pool Project ".
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