Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel
Quenching and partitioning (Q&P) steels are among the most critical third-generation steels for realizing vehicle weight reduction and improving safety performance. It is critical for the structure durability to have an excellent fatigue life of the welds. In this study, Q&P1180 steel was la...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-07-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785422009449 |
| _version_ | 1811188910460502016 |
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| author | Jiazhuang Tian Wu Tao Shanglu Yang |
| author_facet | Jiazhuang Tian Wu Tao Shanglu Yang |
| author_sort | Jiazhuang Tian |
| collection | DOAJ |
| description | Quenching and partitioning (Q&P) steels are among the most critical third-generation steels for realizing vehicle weight reduction and improving safety performance. It is critical for the structure durability to have an excellent fatigue life of the welds. In this study, Q&P1180 steel was laser spot welded (LSW) in order to evaluate the microhardness, mechanical properties, and fatigue behavior of its joints, which were compared with resistance spot welding (RSW). In both types of joining methods, the welded zone is composed of lath martensite with high microhardness value. Due to the martensite tempering, the sub-critical heat affected zone of Q&P RSW welds was soften, resulting in a decrease of 52 HV of microhardness than the LSW joint. The presence of stress concentration in the boundary influenced tensile strength and all-welded samples failed in the boundary. Furthermore, the fatigue limit of the RSW joint (1.139 kN) was about 91.5%t of the LSW joint (1.245 kN). Fatigue specimens of the LSW joint failed between the fusion zone and heat-affected zone because of their higher sensitivity to stress concentration than the RSW joint, resulting in double eyebrow failure and pull-out failure. Fatigue crack originated from the specimen surface and propagated through fatigue striations together with secondary cracks. In addition, it was found that the strength of the base metal has inconsequentially affected the fatigue life of the welds when these welds were produced by the same welding method and have similar geometries. |
| first_indexed | 2024-04-11T14:27:25Z |
| format | Article |
| id | doaj.art-05f1f059810d4c13a3212ea6c7b921bc |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-04-11T14:27:25Z |
| publishDate | 2022-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-05f1f059810d4c13a3212ea6c7b921bc2022-12-22T04:18:48ZengElsevierJournal of Materials Research and Technology2238-78542022-07-011931453159Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steelJiazhuang Tian0Wu Tao1Shanglu Yang2Key Laboratory of Road Construction Technology and Equipment, MOE, Chang'an University, Xi'an, 710064, ChinaShanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, ChinaShanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China; Corresponding author.Quenching and partitioning (Q&P) steels are among the most critical third-generation steels for realizing vehicle weight reduction and improving safety performance. It is critical for the structure durability to have an excellent fatigue life of the welds. In this study, Q&P1180 steel was laser spot welded (LSW) in order to evaluate the microhardness, mechanical properties, and fatigue behavior of its joints, which were compared with resistance spot welding (RSW). In both types of joining methods, the welded zone is composed of lath martensite with high microhardness value. Due to the martensite tempering, the sub-critical heat affected zone of Q&P RSW welds was soften, resulting in a decrease of 52 HV of microhardness than the LSW joint. The presence of stress concentration in the boundary influenced tensile strength and all-welded samples failed in the boundary. Furthermore, the fatigue limit of the RSW joint (1.139 kN) was about 91.5%t of the LSW joint (1.245 kN). Fatigue specimens of the LSW joint failed between the fusion zone and heat-affected zone because of their higher sensitivity to stress concentration than the RSW joint, resulting in double eyebrow failure and pull-out failure. Fatigue crack originated from the specimen surface and propagated through fatigue striations together with secondary cracks. In addition, it was found that the strength of the base metal has inconsequentially affected the fatigue life of the welds when these welds were produced by the same welding method and have similar geometries.http://www.sciencedirect.com/science/article/pii/S2238785422009449Q&P1180 steelLaser spot weldingFatigue lifeMicrohardnessResistance spot welding |
| spellingShingle | Jiazhuang Tian Wu Tao Shanglu Yang Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel Journal of Materials Research and Technology Q&P1180 steel Laser spot welding Fatigue life Microhardness Resistance spot welding |
| title | Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel |
| title_full | Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel |
| title_fullStr | Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel |
| title_full_unstemmed | Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel |
| title_short | Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel |
| title_sort | investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel |
| topic | Q&P1180 steel Laser spot welding Fatigue life Microhardness Resistance spot welding |
| url | http://www.sciencedirect.com/science/article/pii/S2238785422009449 |
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