Process Optimization and Performance of New TBM Disc Cutter Ring Steel

During the tunneling process of high-abrasion stratum with strong impact by tunnel boring machines (TBM), disc cutter rings made of H13 and DC53 steels are prone to failures like wear and chipping. To improve the service life of the cutter ring, a new kind of Cr-Mo-W-V medium carbon alloy cutter ring steel (DQ1) with better hardness and toughness was developed. The effects of the heat treatment process on the microscopic structure and mechanical properties of DQ1 steel were studied by the spectrometer, optical microscope, Rockwell hardness tester, and impact tester. The wear resistance of DQ1, H13, and DC53 steel was compared and analyzed through the abrasive wear test and rock breaking test. The results indicate that outstanding mechanical properties and wear resistance of DQ1 steel were obtained after quenching at 1040°C and tempering at 540°C, the hardness was 4.4 HRC higher than that of H13 steel, and the impact absorption energy was 85.7% higher than that of DC53 steel. In excavating strong impact and high abrasion formations, the average service life of the DQ1 steel cutter ring was increased by 24.6% compared with the H13 steel cutter ring, and the brittle fracture problem common in the DC53 cutter ring did not appear. The research achievements can facilitate to improve the excavation efficiency and reduce the cost of TBM in high strength and high erosion strata.