Wear properties of high-manganese steel strengthened with nano-sized V2C precipitates

초록

In this study, the nano-sized V2C precipitations were introduced in the high-manganese steel (Fe-17Mn-0.9C) matrix to improve the wear-resistance under low-impact abrasive wear. To control the size and distribution of nano-sized V2C precipitations, the different heat treatments (quenching at 1100 degrees C, and tempering at 400, 450, and 500 degrees C) were applied. The microstructure, strengthening mechanisms, and wear properties were investigated. The untempered steel presented low wear-resistance, owing to the small amount of nano-sized V2C precipitates, and the strengthening effect of the micro-sized precipitates with small sizes was not remarkable. With the increase in the tempering temperature, the increase in the size and density of the micro-sized and nano-sized V2C precipitates were much more advantageous due to the thicker and harder work-hardening layer formed, thus improving the wear-resistance. The tempering at 500 degrees C led to excellent wear-resistance, owing to the sizes of the micro-sized precipitates being approximately three times larger than those in the untempered steel, with a significantly increased amount of nano-sized V2C precipitates. The latter led to the formation of a work-hardening layer with a thickness of 3.9 mm on the worn surface, which had work-hardening index values up to 0.643. The results proved that the formation of the work-hardening layer substantially enhanced the wear-resistance, and the strengthening mechanism of the high-manganese steel was dependent on the tempering temperature. Concurrently, the wear mechanisms of the tested steels were transformed from micro-cutting to plastic deformation with increasing tempering temperature.

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