Simulation optimization and experimental research on heat-treatment process for ring remanufacturing of TBM disc cutters

Abstract

In the context of the double carbon target, this study aims to reduce the metal resource consumption caused by the replacement of the failed disc cutter rings of tunnel boring machine (hereafter referred to as cutter rings). For this purpose, for the first time, a cutter-ring remanufacturing method is introduced considering key heat-treatment processes of preheating and post-weld tempering through metal active gas arc welding. First, a finite element model was developed to simulate this remanufacturing process route, establishing the optimal parameter ranges for the preheating and tempering temperatures. Subsequently, a self-developed integrated experimental platform was designed combining heat treatment and surfacing remanufacturing. A three-factor and three-level orthogonal experiment was conducted within the optimized parameter ranges. Further, a weighted comparative and range analysis method is proposed, and the impacts of the critical heat-treatment processes on the remanufacturing performance of the cutter rings exhibiting a uniform wear are investigated, resulting in the identification of the optimal heat-treatment combination. Results revealed that these pivotal heat treatments are instrumental in curbing defects (e.g., cracks) and substantially decreasing the residual stress in remanufactured cutter rings. Furthermore, the post-weld tempering temperature is the primary factor influencing the comprehensive performance and an array of physical and mechanical properties, including indent depth, hardness, shear strength, and impact toughness. The comprehensive performance of the best-produced sample impressively surged by 10.5 % compared to a standard engineering cutter ring.