Study on Microstructure and Properties of Carbidic Austempered Ductile Iron ( CADI)

摘要

As a new kind of engineering structure materials with high strength and toughness, the application ofrnaustempered ductile iron is growing widely in the area of automobile, agricultural machinary, mine, rail way and so on.rnWhereas, because of voiding role of nodular gtraphite existing in the microstructure, it is shown that the abrasive resistance ofrnADI is not very satisfied under abrasive wearing conditions. Therefore, in this paper, the microstructure and properties ofrnaustempered ductile iron with carbides was studied, which is called CADI. It was proven that the austempering temperaturerninfluenced greatly the microstructure, impact toughness, hardness and abrasion resistance of CADI. With increase ofrnaustempering temperature, the acicular ferrite becomes thicker and bigger, the impact toughness rises, and the hardnessrndecreases. But there is a complicated effect of austempering temperature on wet abrasion resistance. The CADI grindingrnball was cast and the field testing was performed. Compared with low chromium cast iron ball, the wastage of CADI ball isrnhalf of that of low chromium cast iron for grinding ore in mill.