Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa
High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (...
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MDPI AG
2021-06-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/11/12/5728 |
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| author | HyeonJeong You Minjung Kang Sung Yi Soongkeun Hyun Cheolhee Kim |
| author_facet | HyeonJeong You Minjung Kang Sung Yi Soongkeun Hyun Cheolhee Kim |
| author_sort | HyeonJeong You |
| collection | DOAJ |
| description | High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels. |
| first_indexed | 2024-03-10T10:13:58Z |
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| id | doaj.art-b004223e0f034f1e9fb7fdeeca098a97 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T10:13:58Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-b004223e0f034f1e9fb7fdeeca098a972023-11-22T01:00:12ZengMDPI AGApplied Sciences2076-34172021-06-011112572810.3390/app11125728Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPaHyeonJeong You0Minjung Kang1Sung Yi2Soongkeun Hyun3Cheolhee Kim4Department of Mechanical and Materials Engineering, Portland State University, Portland, OR 97201, USAJoining R&D Group, Korea Institute of Industrial Technology, Incheon 21999, KoreaDepartment of Mechanical and Materials Engineering, Portland State University, Portland, OR 97201, USADepartment of Materials Science and Engineering, Inha University, Incheon 22212, KoreaDepartment of Mechanical and Materials Engineering, Portland State University, Portland, OR 97201, USAHigh-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.https://www.mdpi.com/2076-3417/11/12/5728high-strength steelautomotivefriction stir weldingrecrystallized zonepartially recrystallized zonetempered zone |
| spellingShingle | HyeonJeong You Minjung Kang Sung Yi Soongkeun Hyun Cheolhee Kim Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa Applied Sciences high-strength steel automotive friction stir welding recrystallized zone partially recrystallized zone tempered zone |
| title | Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa |
| title_full | Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa |
| title_fullStr | Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa |
| title_full_unstemmed | Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa |
| title_short | Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa |
| title_sort | comprehensive analysis of the microstructure and mechanical properties of friction stir welded low carbon high strength steels with tensile strengths ranging from 590 mpa to 1 5 gpa |
| topic | high-strength steel automotive friction stir welding recrystallized zone partially recrystallized zone tempered zone |
| url | https://www.mdpi.com/2076-3417/11/12/5728 |
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