核电阀门修复技术研究现状、典型缺陷及优化方法综述

A Review on Research Status, Typical Defects and Optimization Methods of Side-Axial Repair Technology for Nuclear Power Valves

摘要: 核电阀门密封面长期承受高温高压介质冲刷与循环载荷作用，易产生冲蚀、腐蚀及疲劳损伤，传统整体更换维修存在周期长、成本高、受限空间作业难等瓶颈。本文系统综述了核电阀门密封面增材再制造技术体系：梳理了铁基、镍基及钴基合金修复材料的性能特点与适用工况，为材料选型提供依据；对比分析了激光熔覆、等离子熔覆及钨极氩弧焊的工艺特性、冶金质量及服役可靠性，支撑差异化修复策略制定；针对熔覆层气孔、裂纹及残余应力等缺陷控制难题，探讨了超声冲击处理、激光重熔及基体预热、热处理等辅助工艺的作用机制与优化效果。研究表明，激光熔覆凭借低稀释率与高精度已成为核级阀门精密修复的首选，合理的后处理与辅助工艺组合是实现高性能再制造的关键。

Abstract: The sealing surfaces of nuclear power valves are susceptible to erosion, corrosion and fatigue damage under prolonged exposure to high-temperature, high-pressure media and cyclic loading. Conventional replacement maintenance, however, suffers from extended downtime, high costs and operational constraints in confined spaces. This paper presents a comprehensive review of surface remanufacturing technologies for nuclear valve sealing surfaces. The performance characteristics and applicable service conditions of Fe-based, Ni-based and Co-based repair alloys are summarized to guide material selection. The process characteristics, metallurgical quality and service reliability of laser cladding, plasma cladding and gas tungsten arc welding are comparatively analyzed to inform differentiated repair strategies. To address critical defects including porosity, cracking and residual stress in deposited layers, the mechanisms and efficacy of auxiliary processes such as ultrasonic impact treatment, laser remelting, substrate preheating and post-weld heat treatment are discussed. It is evident that laser cladding has become the preferred technique for precision repair of nuclear-grade valves owing to its low dilution rate and high dimensional accuracy; moreover, an appropriate combination of post-processing and auxiliary treatments is essential for achieving high-performance remanufacturing.