Wear resistance of hot rolled FeNiCr steel with various austempering temperature

In this study, the effect of bainite structure, which was formed from a series of hot rolling followed by austempering, on the wear property of FeNiCr steel was studied. During the hot rolling process, the FeNiCr samples were subjected to austenization at 1050 °C for 90 min then rolled at several different reductions, which are 50, 70, or 80%. The hot rolled samples then immediately austempered at various temperatures for each reduction level. The austempering temperatures used were 300, 350, or 400 °C. At each temperature level, the samples were hold for 30 min followed by air cooling. From the Scanning Electron Microscope (SEM) images, the sample structure is not only consisting of bainite (B) mostly in a lath form, but also islands of martensite/retained austenite (M/RA). The higher the reduction level of hot rolling process seems to promote the growth of the M/RA islands more than the B phase. This leads to a proportional relation of reduction level during hot rolling process with hardness of all austempered samples. However, the wear property of the samples does not show the same trend as the hardness. Only the 300 °C sample has an increase in its wear property as the hot rolled reduction increase. The 350 and 400 °C samples show a decrease in their wear property as the hot rolled reduction increases. Both, the lowest specific wear rate, 3.006624 x 10−6 mm3/mm, and the highest hardness value, 50.1 HRC, are obtained from the 80% hot rolled - 300 °C austempered sample.