Phase transformation of an austempered ductile iron during an erosion process

Ductile iron specimens of similar to3.5 mass% C and similar to2.8 mass% Si were austempered at 420degreesC for 0.5hsimilar to24h. These upper bainitic austempered ductile iron (ADI) specimens were 90degrees-eroded by Al2O3 particles of similar to275 mum grit size under the average particle velocity of 73 m(.)s(-1) to understand phase transformation at the erosion surface. According to the experimental results, the retained austenite content and the carbon content of bainitic ferrite decreases through phase transformation during erosion. After erosion, the retained austenite and the high carbon content bainitic ferrite form epsilon-carbide, another carbide and ferrite. The other austempering carbide of the remaining matrix also transforms into epsilon-carbide in the erosion process.