EFFECT OF AUSTEMPERED TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF B-BEARING CADI

Abstract

Carbidic austempered ductile iron (CADI) is a new type of wear-resistant material with high performance developed in recent years. The effect of austempered temperature on the microstructure and properties of high B-bearing CADI was investigated. Boron is an element that significantly interferes with the spheroidization process. When the boron content in CADI is high, the crystallization of spheroidal graphite in the as-cast microstructure is hindered, and its roundness, spheroidization rate, and volume fraction are significantly reduced. The results of its heat treatment process show that with the increase of austempered temperature, the volume fraction of residual austenite in the matrix increased, the size of acicular ferrite becomes coarser, and the ferrite also increases significantly, and the macroscopic hardness and wear resistance of the specimens gradually decreased.