University of Oulu

Khedr M, Hamada A, Järvenpää A, Elkatatny S, Abd-Elaziem W. Review on the Solid-State Welding of Steels: Diffusion Bonding and Friction Stir Welding Processes. Metals. 2023; 13(1):54.

Review on the solid-state welding of steels : diffusion bonding and friction stir welding processes

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Author: Khedr, Mahmoud1,2; Hamada, Atef2; Järvenpää, Antti2;
Organizations: 1Mechanical Engineering Department, Faculty of Engineering at Shoubra, Benha University, Cairo 11629, Egypt
2Kerttu Saalasti Institute, Future Manufacturing Technologies (FMT), University of Oulu, Pajatie 5, FI-85500 Nivala, Finland
3Mechanical Engineering Department, Faculty of Engineering, Suez Canal University, Ismailia 41522, Egypt
4Department of Mechanical Design and Production Engineering, Faculty of Engineering, Zagazig University, Zagazig 44519, Egypt
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7.5 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2022
Publish Date: 2023-08-23


Solid-state welding (SSW) is a relatively new technique, and ongoing research is being performed to fulfill new design demands, deal with contemporary material advancements, and overcome welding defects associated with traditional welding techniques. This work provides an in-depth examination of the advancements in the solid-state welding of steels through diffusion bonding (DB) and friction stir welding (FSW). Considerable attention was given to DB of steel, which overcame the difficulties of segregation, cracking, and distortion stresses that are usually formed in liquid-phase welding techniques. The defects that affected DB included two types: two-dimensional defects of a metallic lattice, i.e., phases and grain boundaries, and three-dimensional defects, i.e., precipitation. FSW, on the other hand, was distinguishable by the use of relatively low heat input when compared to fusion welding processes such as tungsten inert gas (TIG), resulting in the formation of a limited heat-affected zone. Moreover, fine grain structures were formed in the FSW interface because of the stirring tool’s severe plastic deformation, which positively affected the strength, ductility, and toughness of the FSW joints. For instance, higher strength and ductility were reported in joints produced by FSW than in those produced by TIG. Nevertheless, the HAZ width of the specimens welded by FSW was approximately half the value of the HAZ width of the specimens welded by TIG. Some defects associated with FSW related to the diffusion of elements, such as C/Cr atoms, through the weld zone, which affected the local chemical composition due to the formation of rich/depleted regions of the diffused atoms. Moreover, the lack-of-fill defect may exist when inappropriate welding conditions are implemented. On the other hand, the stirring tool was subjected to extensive wear because of the high hardness values, which negatively affected the economical usage of the FSW process. A summary of the results is presented, along with recommendations for future studies aimed at addressing existing difficulties and advancing the solid-state technology for steel.

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Series: Metals
ISSN: 2075-4701
ISSN-E: 2075-4701
ISSN-L: 2075-4701
Volume: 13
Issue: 1
Article number: 54
DOI: 10.3390/met13010054
Type of Publication: A2 Review article in a scientific journal
Field of Science: 216 Materials engineering
Funding: This research was funded by [financial assistance of Business Finland, project FOSSA- Fossil-Free Steel Applications] grant number [5498/31/2021].
Copyright information: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (