Study On The Microstructures And Properties Of New Type High Strength Gray Cast Iron With High Carbon Equivalent

The history of gray cast iron as structure material is very long. The gray cast iron has the properties of wear resistance, hot resistance, oxidation resistance, erosion resistance, good shock absorption. At the same time, the gray cast iron has some superiority such as low melting temperature, good fluidity, good machining properties, simple production equipment, simple molding process and low production-cost compared with other alloy. So, the proportion of gray cast iron in cast iron casting is very huge. Some data show, the gray cast iron casting accounts for 72 percent in all cast iron casting for a time. But the strength of gray iron is comparatively low, so it is competed powerfully by the compacted graphite cast iron, the colored metal and the plastic etc., and the trend of requirement quantity is decreasing.So far, some work-pieces such as big horsepower engine cylinder block casting must be made in gray cast iron. Thereby, people have to turn the line of sight back to gray cast iron, and study the possibility of enhancing further the strength of the gray cast iron. During the past years, people do a great deal and systemic study on solidification course, inoculating, modifying treatment processing and the influence of alloy on structures and properties of high strength (σb≥300MPa) gray cast iron with low carbon equivalent (CE=3.8), while less work has been carried out on the high strength gray cast iron with high carbon equivalent (CE=3.9%~4.2).