Effect of tempering temperature on erosion mechanisms of AISI D2 tool steel: experimental and FEA

This study investigates the effect of tempering temperature on the hardness, microstructure, retained austenite (RA), and erosion behaviour of AISI D2 tool steel using experiments and finite-element analysis (FEA). Specimens were quenched at 1273 K and tempered at 573–773 K under low-temperature tempering (TLT), medium-temperature tempering (TMT), and high-temperature tempering (THT) conditions. Increasing tempering temperature promoted RA decomposition and secondary-carbide precipitation, resulting in increased hardness from QTLT to QTHT. However, erosion resistance did not directly correlate with either hardness or RA content. QTLT exhibited the lowest erosion rate, whereas QTMT showed the highest. SEM observations revealed that QTMT experienced the most severe micro-cutting and lip formation, while QTLT predominantly exhibited ploughing. FEA further demonstrated that QTMT exhibited the highest surface stress, plastic strain, and crater depth, whereas QTLT showed the lowest values, in good agreement with the experimental results. Furthermore, the validated model was extended to investigate the effects of impact angle, particle size, and particle velocity, demonstrating its capability to predict erosion behaviour under different operating conditions. These findings provide mechanistic insight into the erosion behaviour of tempered AISI D2 tool steel and guidance for optimising tempering conditions in erosive environments.