*Editorial* **Development of Laser Welding and Surface Treatment of Metals**

**Aleksander Lisiecki**

Department of Welding Engineering, Faculty of Mechanical Engineering, Silesian University of Technology, Konarskiego 18A Street, 44-100 Gliwice, Poland; aleksander.lisiecki@polsl.pl

**Abstract:** This Special Issue on Development of Laser Welding and Surface Treatment of Metals contains as many as twenty-two research articles mainly related to the application of lasers, but also on other welding processes that may be competitive to laser technologies under specific conditions. Despite the introduction of lasers for material processing in the 1960s, the continuous development of laser devices also leads to the development and expansion of laser technology applications. This Special Issue is a compendium of knowledge in the field of fusion welding, the manufacturing of surface layers and coatings with increased wear resistance and tribological characteristics, as well as corrosion resistance and the characterization of coatings and surface layers. The topics of the presented research articles include aspects related to laser welding (eight articles), especially technological conditions, the properties of different types of joints, and analytical and numerical aspects of modelling the laser heat sources. The second dominant issue concerns laser cladding and laser surface treatment of different ferrous and nonferrous metallic and composite materials (six articles). In addition, there are interesting results of the study of fusion welding under forced cooling of the deposit or underwater conditions (four articles), results on the characterization of wear resistance coating produced by different technologies that can be competitive for laser cladding (three articles), and an original study on local strengthening of the thin-walled structure by laser treatment (one article). This Special Issue provides very wide and valuable knowledge based on theoretical and empirical study in the field of laser and fusion welding, laser and related coating technologies, characterization of coatings, and wear phenomena.

**Keywords:** welding; laser processing; joining; tribology; cladding; properties of surface layers

**Citation:** Lisiecki, A. Development of Laser Welding and Surface Treatment of Metals. *Materials* **2022**, *15*, 1765. https://doi.org/10.3390/ ma15051765

Received: 3 February 2022 Accepted: 20 February 2022 Published: 26 February 2022

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