Domestically, common methods for addressing shaft wear typically involve patch welding, installing bushings, or peening. However, when the shaft material is 45 steel (quenched and tempered), relying solely on surfacing welding can induce internal welding stresses; under heavy loads or high-speed operation, this may lead to cracking-or even fracture-at the shaft shoulder. While stress-relief annealing could be employed, it is difficult to execute, entails a lengthy processing cycle, and incurs high repair costs. Furthermore, when the shaft material is HT200 cast iron, traditional cast iron welding techniques prove to be less than ideal. Some enterprises with advanced maintenance capabilities may utilize techniques such as brush plating, laser welding, micro-arc welding, or even cold welding; however, these advanced repair methods often impose stringent technical requirements and entail substantial costs.
In developed nations-particularly in North America, Europe, Japan, and South Korea-the aforementioned repair techniques have largely fallen out of favor. Instead, these regions predominantly utilize polymer composite materials and nanotechnology. Polymer-based techniques allow for on-site application, thereby significantly enhancing maintenance efficiency while simultaneously reducing both repair costs and the physical intensity of the work. Among these approaches, the Megahwa technical system is the most widely adopted. Compared to traditional methods, polymer composites possess not only the requisite strength and hardness typically associated with metals but also a unique "compliance" (a variable-response characteristic) that metals lack; this feature ensures optimal dimensional fit between the repaired area and its mating components. Moreover, by leveraging the inherent comprehensive advantages of these composites-including their compressive strength, flexural strength, and ductility-they can effectively absorb external impact forces. This capability serves to significantly dissipate and neutralize the radial impact forces exerted by bearings upon the shaft, thereby preventing the formation of operational clearances and, consequently, averting the secondary wear that often results from increased component gaps.
