University of Oulu

Hietala, M.; Jaskari, M.; Ali, M.; Järvenpää, A.; Hamada, A. Dissimilar Laser Welding of Austenitic Stainless Steel and Abrasion-Resistant Steel: Microstructural Evolution and Mechanical Properties Enhanced by Post-Weld Heat Treatment. Materials 2021, 14, 5580. https://doi.org/10.3390/ma14195580

Dissimilar laser welding of austenitic stainless steel and abrasion-resistant steel : microstructural evolution and mechanical properties enhanced by post-weld heat treatment

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Author: Hietala, Mikko1; Jaskari, Matias1; Ali, Mohammed2,3;
Organizations: 1Kerttu Saalasti Institute, University of Oulu, FI-85500 Nivala, Finland
2Materials and Mechanical Engineering Unit, University of Oulu, Pentti Kaiteran Katu 1, FI-90014 Oulu, Finland
3Steel Technology Department, Central Metallurgical Research and Development Institute, Helwan 11421, Egypt
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7.7 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2021111755771
Language: English
Published: Multidisciplinary Digital Publishing Institute, 2021
Publish Date: 2021-11-17
Description:

Abstract

In this study, ultra-high-strength steels, namely, cold-hardened austenitic stainless steel AISI 301 and martensitic abrasion-resistant steel AR600, as base metals (BMs) were butt-welded using a disk laser to evaluate the microstructure, mechanical properties, and effect of post-weld heat treatment (PWHT) at 250 °C of the dissimilar joints. The welding processes were conducted at different energy inputs (EIs; 50–320 J/mm). The microstructural evolution of the fusion zones (FZ) in the welded joints was examined using electron backscattering diffraction (EBSD) and laser scanning confocal microscopy. The hardness profiles across the weldments and tensile properties of the as-welded joints and the corresponding PWHT joints were measured using a microhardness tester and universal material testing equipment. The EBSD results showed that the microstructures of the welded joints were relatively similar since the microstructure of the FZ was composed of a lath martensite matrix with a small fraction of austenite. The welded structure exhibited significantly higher microhardness at the lower EIs of 50 and 100 J/mm (640 HV). However, tempered martensite was promoted at the high EI of 320 J/mm, significantly reducing the hardness of the FZ to 520 HV. The mechanical tensile properties were considerably affected by the EI of the as-welded joints. Moreover, the PWHT enhanced the tensile properties by increasing the deformation capacity due to promoting the tempered martensite in the FZ.

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Series: Materials
ISSN: 1996-1944
ISSN-E: 1996-1944
ISSN-L: 1996-1944
Volume: 14
Issue: 19
Article number: 5580
DOI: 10.3390/ma14195580
OADOI: https://oadoi.org/10.3390/ma14195580
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
214 Mechanical engineering
Subjects:
Funding: This research was funded by the European Regional Development Fund (ERDF) of the European Union through the Efficient Structures (TeRa) project in the city of Nivala, Nivala Industrial Park Ltd., NIHAK Nivala, which is a Haapajarvi region registered association.
Copyright information: © 2021 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 (https://creativecommons.org/licenses/by/4.0/).
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