Ti-V-Nb precipitation refinement via aging time modification for wear resistance improving in nitrogen micro-alloyed high manganese steels

Abstract

Abstract It is very beneficial for wear resistance improving how to acquire refined precipitates with diffuse distribution. In high manganese cast steels, Ti-V-Nb microalloying is a useful method to promote carbide and carbonitride precipitating, and the nitrogen addition could accelerate the precipitation. Therefore, Aging time modification is a practical option to implement the precipitation strength and wear resistance of micro-alloyed high manganese steels. In this work, the quantities and distribution of precipitates were collaboratively regulated by Ti-V-Nb-N microalloying and aging time variations (water quenching at 1100°C followed by holding at 400°C for 24, 60, and 84 hours, respectively, designated AT24, AT60, and AT84) to improve the wear resistance of manganese steels. The results have shown that solid solution aging treatment could effectively refine micron-sized precipitates in high manganese steels compared to as-cast (AS) steels while inducing the precipitation of nanoscale precipitates. With increasing aging time, the number of nanoscale precipitates increased and then decreased, and the nanoscale precipitates were most numerous and uniformly distributed in AT60, which exhibited the most excellent comprehensive mechanical properties. Refined micron-size precipitates cooperating with diffusely distributed nanoscale precipitates increased the matrix resistance to abrasives resulting in less wear weight loss and improved wear resistance of AT60. Compared to as-cast steel, the wear mechanisms of the tested steels were transformed from wide and deep pits to shallow grooves and micro-cutting by prolonging the aging time.