Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590
Resistance spot-welding of dissimilar metals, medium manganese TRIP steel 7Mn and DP590, is carried out. The effects of single-pulse welding parameters and a double-pulse-tempering current on the quality characteristic parameters and mechanical properties of 7Mn/DP590 spot-welded joints are studied....
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| Format: | Article |
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MDPI AG
2022-09-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/12/10/1596 |
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| author | Fufa Wei Yunming Zhu Yifeng Tian Hongning Liu Yongqiang Zhou Zhengqiang Zhu |
| author_facet | Fufa Wei Yunming Zhu Yifeng Tian Hongning Liu Yongqiang Zhou Zhengqiang Zhu |
| author_sort | Fufa Wei |
| collection | DOAJ |
| description | Resistance spot-welding of dissimilar metals, medium manganese TRIP steel 7Mn and DP590, is carried out. The effects of single-pulse welding parameters and a double-pulse-tempering current on the quality characteristic parameters and mechanical properties of 7Mn/DP590 spot-welded joints are studied. The welding process parameters are optimized using the control variable method. The results show that the optimal process parameters under a single pulse are as follows: electrode pressure: 4.5 kN, welding current: 9 kA and welding time: 300 ms. The failure mode of the welding joint is partial pull-out failure (PF-TT). The welding parameters have great influence on the nugget diameter and thickness reduction. Expulsion, crack and shrinkage are displayed in the joint under high electrode pressure. Softening occurs in the heat-affected zone due to a strong halo effect in the single-pulse weld. The tempering zone on the DP590 side is 202.49 HV, which is the lowest hardness point, while the hardness of the nugget zone is 450 HV. The addition of the tempering current homogenizes the microstructure with different failure paths and eliminates the stress. The tensile shear force of the joint increases by 17.13%. The 7Mn Steel/DP590 resistance spot-welding joint is from the fusion line to the center of the nugget, and the microstructure is composed of plane crystal, cellular crystal, dendritic crystal and columnar crystal, in turn. The nugget zone is composed of lath martensite and a small amount of residual austenite. Fine quasi-spherical and lamellar interbedded cementites are formed in the tempering zone of the DP590-side heat-affected zone. |
| first_indexed | 2024-03-09T19:48:41Z |
| format | Article |
| id | doaj.art-d046256c9f7a4a5c9e04e25ac4c5b4c3 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T19:48:41Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-d046256c9f7a4a5c9e04e25ac4c5b4c32023-11-24T01:17:34ZengMDPI AGMetals2075-47012022-09-011210159610.3390/met12101596Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590Fufa Wei0Yunming Zhu1Yifeng Tian2Hongning Liu3Yongqiang Zhou4Zhengqiang Zhu5Advanced Manufacturing School, Nanchang University, Nanchang 330047, ChinaAdvanced Manufacturing School, Nanchang University, Nanchang 330047, ChinaAdvanced Manufacturing School, Nanchang University, Nanchang 330047, ChinaAdvanced Manufacturing School, Nanchang University, Nanchang 330047, ChinaAdvanced Manufacturing School, Nanchang University, Nanchang 330047, ChinaAdvanced Manufacturing School, Nanchang University, Nanchang 330047, ChinaResistance spot-welding of dissimilar metals, medium manganese TRIP steel 7Mn and DP590, is carried out. The effects of single-pulse welding parameters and a double-pulse-tempering current on the quality characteristic parameters and mechanical properties of 7Mn/DP590 spot-welded joints are studied. The welding process parameters are optimized using the control variable method. The results show that the optimal process parameters under a single pulse are as follows: electrode pressure: 4.5 kN, welding current: 9 kA and welding time: 300 ms. The failure mode of the welding joint is partial pull-out failure (PF-TT). The welding parameters have great influence on the nugget diameter and thickness reduction. Expulsion, crack and shrinkage are displayed in the joint under high electrode pressure. Softening occurs in the heat-affected zone due to a strong halo effect in the single-pulse weld. The tempering zone on the DP590 side is 202.49 HV, which is the lowest hardness point, while the hardness of the nugget zone is 450 HV. The addition of the tempering current homogenizes the microstructure with different failure paths and eliminates the stress. The tensile shear force of the joint increases by 17.13%. The 7Mn Steel/DP590 resistance spot-welding joint is from the fusion line to the center of the nugget, and the microstructure is composed of plane crystal, cellular crystal, dendritic crystal and columnar crystal, in turn. The nugget zone is composed of lath martensite and a small amount of residual austenite. Fine quasi-spherical and lamellar interbedded cementites are formed in the tempering zone of the DP590-side heat-affected zone.https://www.mdpi.com/2075-4701/12/10/1596resistance spot-weldingmedium manganese TRIP steelmicrostructuremechanical propertiesDP590 |
| spellingShingle | Fufa Wei Yunming Zhu Yifeng Tian Hongning Liu Yongqiang Zhou Zhengqiang Zhu Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590 Metals resistance spot-welding medium manganese TRIP steel microstructure mechanical properties DP590 |
| title | Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590 |
| title_full | Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590 |
| title_fullStr | Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590 |
| title_full_unstemmed | Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590 |
| title_short | Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590 |
| title_sort | resistance spot welding of dissimilar metals medium manganese trip steel and dp590 |
| topic | resistance spot-welding medium manganese TRIP steel microstructure mechanical properties DP590 |
| url | https://www.mdpi.com/2075-4701/12/10/1596 |
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