摘要: As the main use of TBM (tunnel boring machine) cutter ring (DC53 steel) currently is difficult to meet the requirements of high wear resistance and high toughness synchronously in its service environment, a new HWR0 steel with 4%Cr-3%V for TBM cutter ring has been developed to control carbides in steel. Precipitation behavior of carbides in HWR0 steel was investigated through theoretical calculation by Thermo-Calc and experimental measurement using scanning electron microscope, energy dispersive spectrometer, electron probe X-ray micro-analyzer, and laser particle size analyzer. The results show that three different carbides are precipitated during cooling. And the as-cast electroslag remelting ingot of HWR0 steel primarily consists of many blocky or strip-like MC distributed along grain boundaries, few chrysanthemum-like M₆C concentrated at grain boundary intersections, and a large quantity of fine M₂₃C₆ and M₆C dispersed in the matrix. Compared with DC53 steel, HWR0 steel has more high-hardness carbides MC, which are discontinuously distributed at the grain boundaries, achieving the dual improvement of wear resistance and impact toughness. Cooling rates significantly influence the carbides distribution and grain size. A slower cooling rate exacerbates the segregation of alloying elements, which leads to the localized enrichment of Mo and the subsequent precipitation of M₆C carbides at grain boundary intersections. In contrast, faster cooling rate decreases the element segregation, promotes carbide nucleation and limits the space for carbides growth, which results in finer size and distribution of carbides and grains. Higher cooling rates yield a more homogeneous microstructure with uniform MC compositions and promote the preferential formation of M₆C carbides along grain boundaries, which enhances the mechanical properties.