Study on the Wear Resistance of In-situ NbC/H13 Steel Composites

Author of the article:LIU Zhou, ZHOU Mojin, JIANG Yehua, SUI Yudong

Author's Workplace：National & Local Joint Engineering Research Center of Advanced Metal Solidification Forming and Equipment Technology, Kunming University of Science and Technology, Kunming 650000, China

Key Words： in situ; NbC; H13 steel; microstructure; impact toughness; wear resistance

Abstract：H13 steel is used as a shield machine cutter ring material, mainly for breaking hard rock. In the process of shield machine tunneling, the wear and tear of the cutter ring is inevitable, and excessive wear and tear will lead to areduction in tunneling efficiency and increase the construction risk. To improve the wear resistance of H13 steel, in situ NbC/H13 steel composites with volume fractions of 1%, 3% and 5% were prepared by the gravity casting in situ method. Metallographic microscope and scanning electron microscope were used to analyse the physical composition and microstructure of the composites, and the impact toughness and abrasive wear properties of NbC/H13 steel composites with different volume fractions were studied using an impact testing machine and a three-body abrasive wear testing machine. The results show
that the prepared composites are dense and the NbC reinforcing phase is diffusely distributed in the matrix. With the increasing volume fraction of the reinforcing phase, the shape of the reinforcing phase changes from reticular to rod-shaped and granular. The impact toughness of the composites decreases with the increasing volume fraction of the reinforcing phase. When the NbC content is 5%(volume fraction), the impact toughness reaches the minimum value of 6.5 J. The results of three-body abrasive wear show that with the increase of NbC volume fraction, the wear of the steel matrix by the abrasive is effectively reduced, thus further improving the wear resistance of the composites. Compared with the matrix material, the wear resistance is increased by 2.1 times.