Advanced welding processes for structural materials are gaining increasing importance for strategic applications in nuclear, aerospace, automobile, and defence sectors. These processes have been designed keeping in view the criterion of minimal stress generation, microstructure retentivity, and process reproducibility. Narrow gap laser welding (NGLW) is one such advanced welding technique that has been developed in the past decade owing to its fabricate-ability of thick-section steels at high welding speeds. Of the many advantages, several characteristics of the process outperform the traditional arc welding processes as well as single-pass autogenous laser welding, including process flexibility, increased welding productivity, excellent weld properties, and the potential for automation. This paper provides a state-of-the-art technological review on the NGLW process primarily for structural steels covering several topics including the effect of process parameters, structure-property relationship, and induced defects and residual stresses of NGLWed joints. A list of future research recommendations based on several research gaps is also reported in this article.

结构材料的高级焊接工艺对于核，航空，汽车和国防领域的战略应用越来越重要。设计这些过程时要考虑到最小应力生成，微观结构保持性和过程可重复性的标准。窄间隙激光焊接（NGLW）是近十年来发展起来的一种先进焊接技术，这是由于其在高焊接速度下可加工厚型钢的能力。在许多优点中，该过程的几个特征优于传统的电弧焊过程以及单程自生激光焊接，包括过程灵活性，提高的焊接生产率，出色的焊接性能以及自动化的潜力。本文主要针对结构钢提供了有关NGLW工艺的最新技术综述，涵盖了多个主题，包括工艺参数的影响，结构-特性关系以及NGLWed接头的诱发缺陷和残余应力。本文还报告了基于一些研究空白的未来研究建议列表。