The Effect of Silicon Percentage and Shot Peening Operation on Mechanical Properties of Hadfield Steel Containing 17% Manganese

The present study examines the effect of shot peening on the wear behavior of austenitic high- manganese steels in both low and high silicon. For this purpose, austenitic steel with 17 wt % of manganese was cast with 0.6 and 6 wt % of Si. Surface work hardening was performed by using a shot peening device for 15 and 30 min on the samples followed by hardness, impact and wear tests by the dry sand-rubber wheel method. The results showed an intensive reduction of the impact energy from 120 to 7 J and an increase in hardness from 290 to 380 HV in the un-shot peened samples due to the presence of carbide with an increment of silicon percentage. On the other hand, hardness had an enhancing trend owing to the surface work hardening of the samples as a result of shot peening operation. The highest hardness of steel was related to high- silicon–high manganese sample shot peened for 30 min. Accordingly, the highest wear resistance was observed in the same sample. This can be attributed to the presence of carbides precipitation and their sufficient distribution in the matrix of the high-silicon sample, work hardening due to the austenite to martensitic transformation as well as nanocrystallization of the grains on the surface because of the shot-peening process. Studying the wear surfaces showed scratches as a result of the abrasive wear mechanism. Also, the number and depth of the grooves decreased by increasing the hardness.