首先分析了高炉风口小套的几种主要的失效形式以及常见的失效位置，简要指出目前紫铜风口小套存在的问题。随后系统综述了风口小套(铜材料)表面防护技术的研究现状，重点介绍了共渗、堆焊和喷涂三大工艺的应用进展。归纳总结了各种工艺的技术原理、防护材料选择以及强化机理。通过对比三大工艺的优缺点得出，堆焊工艺能获得与铜基体呈冶金结合的耐磨防护层，最具应用前景。但是目前的研究主要致力于提高铜表面的硬度和耐磨性，而忽略了防护层对导热性的影响。因此，在风口小套表面研发一种与基体呈冶金结合、工作性能优异、对整体导热系数影响小的梯度涂层，是未来风口小套长寿化的重点研究方向。

Firstly, several main failure modes and common failure positions of tuyere small sleeve of blast furnace were analyzed, and the problems of tuyere small sleeve at present were pointed out. Then, the research status of surface protection technology for tuyere small sleeve (copper materials) was systematically reviewed, and the application progress of co-penetration, surfacing welding and spraying were mainly introduced. The technical principles, material selection and strengthening mechanism of various processes were summarized. By comparing the three processes, it is concluded that the surfacing welding process can obtain the wear-resistant coatings which is metallurgically bonded with copper substrate, which has the most application prospect. But the current research focused on improving the hardness and wear resistance of copper surface, while ignoring the effect of protective coatings on thermal conductivity. Therefore, preparing a gradient coating on the surface of tuyere small sleeve which is metallurgically combined with the substrate, has excellent working performance, and has little influence on the thermal conductivity of overall is an important research direction for the longevity of the tuyere small sleeve in the future.