Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance
Third-generation advanced high-strength steels (3G-AHSS) are typically galvanized to prevent corrosion of the outer body structure. However, the zinc coating on the surface, combined with the locally elevated temperatures generated during the resistance spot welding (RSW) process, can provide the pr...
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| Format: | Article |
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MDPI AG
2023-02-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/13/3/491 |
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| author | Abdelbaset R. H. Midawi Meet Patel Mohammad Shojaee Kate Pearson Oleksii Sherepenko Hassan Ghassemi-Armaki Elliot Biro |
| author_facet | Abdelbaset R. H. Midawi Meet Patel Mohammad Shojaee Kate Pearson Oleksii Sherepenko Hassan Ghassemi-Armaki Elliot Biro |
| author_sort | Abdelbaset R. H. Midawi |
| collection | DOAJ |
| description | Third-generation advanced high-strength steels (3G-AHSS) are typically galvanized to prevent corrosion of the outer body structure. However, the zinc coating on the surface, combined with the locally elevated temperatures generated during the resistance spot welding (RSW) process, can provide the prerequisites for liquid metal embrittlement (LME). This work uses two strategies to control LME crack formation: current pulsation and varying the electrode geometry. These two methods were compared to a baseline welding schedule for a 3G-980-GI coated AHSS. The effectiveness of each method was discussed in terms of the overall weld cracking index and local cracking index. The results showed that increasing the current pulses results in a slower energy input into the weld, which can help to reduce LME crack formation. Introducing more pulses (five to seven pulses) reduced LME crack formation while maintaining the same welding time. Regarding the electrode geometry, the results showed an increase in LME cracking index for currents below the expulsion level Imax-10% when the electrode face diameter increased, whereas at the current level Imax-200A, the electrode radius was the most important factor to control LME crack index. For the current level above the expulsion, Imax+10%, a drastic decrease in the LME cracking index was observed when a large electrode surface diameter was used. The electrode radius was not a significant factor in controlling LME. The mechanical properties of selected conditions were examined using the lap shear test and the results showed no significant effect of LME cracks on the shear tensile strength. The location of the failure indicated that most of the cracks are located in the indented area (type A), which does not influence the lap shear strength. |
| first_indexed | 2024-03-11T06:11:01Z |
| format | Article |
| id | doaj.art-195b7d8a680e4c2d9ee31ba92752b583 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-11T06:11:01Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-195b7d8a680e4c2d9ee31ba92752b5832023-11-17T12:38:30ZengMDPI AGMetals2075-47012023-02-0113349110.3390/met13030491Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical PerformanceAbdelbaset R. H. Midawi0Meet Patel1Mohammad Shojaee2Kate Pearson3Oleksii Sherepenko4Hassan Ghassemi-Armaki5Elliot Biro6CAMJ Group, Mechanical and Mechatronic Engineering Department, University of Waterloo, Waterloo, ON N2L 3G1, CanadaCAMJ Group, Mechanical and Mechatronic Engineering Department, University of Waterloo, Waterloo, ON N2L 3G1, CanadaCAMJ Group, Mechanical and Mechatronic Engineering Department, University of Waterloo, Waterloo, ON N2L 3G1, CanadaCAMJ Group, Mechanical and Mechatronic Engineering Department, University of Waterloo, Waterloo, ON N2L 3G1, CanadaCAMJ Group, Mechanical and Mechatronic Engineering Department, University of Waterloo, Waterloo, ON N2L 3G1, CanadaManufacturing Systems Research Laboratory, General Motors R&D, Warren, MI 48092, USACAMJ Group, Mechanical and Mechatronic Engineering Department, University of Waterloo, Waterloo, ON N2L 3G1, CanadaThird-generation advanced high-strength steels (3G-AHSS) are typically galvanized to prevent corrosion of the outer body structure. However, the zinc coating on the surface, combined with the locally elevated temperatures generated during the resistance spot welding (RSW) process, can provide the prerequisites for liquid metal embrittlement (LME). This work uses two strategies to control LME crack formation: current pulsation and varying the electrode geometry. These two methods were compared to a baseline welding schedule for a 3G-980-GI coated AHSS. The effectiveness of each method was discussed in terms of the overall weld cracking index and local cracking index. The results showed that increasing the current pulses results in a slower energy input into the weld, which can help to reduce LME crack formation. Introducing more pulses (five to seven pulses) reduced LME crack formation while maintaining the same welding time. Regarding the electrode geometry, the results showed an increase in LME cracking index for currents below the expulsion level Imax-10% when the electrode face diameter increased, whereas at the current level Imax-200A, the electrode radius was the most important factor to control LME crack index. For the current level above the expulsion, Imax+10%, a drastic decrease in the LME cracking index was observed when a large electrode surface diameter was used. The electrode radius was not a significant factor in controlling LME. The mechanical properties of selected conditions were examined using the lap shear test and the results showed no significant effect of LME cracks on the shear tensile strength. The location of the failure indicated that most of the cracks are located in the indented area (type A), which does not influence the lap shear strength.https://www.mdpi.com/2075-4701/13/3/491LME cracksRSWelectrode geometrycurrent pulsing3G-AHSSlap shear |
| spellingShingle | Abdelbaset R. H. Midawi Meet Patel Mohammad Shojaee Kate Pearson Oleksii Sherepenko Hassan Ghassemi-Armaki Elliot Biro Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance Metals LME cracks RSW electrode geometry current pulsing 3G-AHSS lap shear |
| title | Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance |
| title_full | Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance |
| title_fullStr | Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance |
| title_full_unstemmed | Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance |
| title_short | Effect of Liquid Metal Embrittlement Indent Cracks on Zinc Coated 3rd Generation AHSS Mechanical Performance |
| title_sort | effect of liquid metal embrittlement indent cracks on zinc coated 3rd generation ahss mechanical performance |
| topic | LME cracks RSW electrode geometry current pulsing 3G-AHSS lap shear |
| url | https://www.mdpi.com/2075-4701/13/3/491 |
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