Effect of weld line shape on laser welded joint strength of automotive high-strength steel sheets

2019 ◽  
Vol 33 (1-3) ◽  
pp. 73-82
Author(s):  
Asato Hara ◽  
Yasushi Kitani
Keyword(s):  
Line Shape ◽  
High Strength Steel ◽  
Joint Strength ◽  
Welded Joint ◽  
Weld Line ◽  
High Strength ◽  
Steel Sheets

scholarly journals Hemming with Pre-Bent Inner Sheet for Joining Ultra-High Strength Steel Sheets of Automobile Parts

2020 ◽  
Vol 4 (3) ◽  
pp. 77
Author(s):  
Yohei Abe ◽  
Wataru Ijichi ◽  
Ken-ichiro Mori ◽  
Kazuma Nakagawa
Keyword(s):  
High Strength Steel ◽  
Joint Strength ◽  
Welded Joint ◽  
High Strength ◽  
Peel Strength ◽  
Joint Work ◽  
Steel Sheets ◽  
Ultra High Strength Steel ◽  
Automobile Parts ◽  
Joining Process

In order to join two ultra-high strength steel sheets with low ductility for automobile parts, a joining process by hemming with a pre-bent inner sheet was developed. In this joining, the pre-bent inner sheet instead of the conventional flat inner sheet was used to relax the deformation concentration of the outer sheet. Although 780 MPa steel sheets were joined without the pre-bent inner sheet, a fracture in the outer sheet occurred in joining the 980 MPa sheets due to the low ductility of the sheets. The 980 MPa and 1180 MPa sheets were successfully joined by hemming with the pre-bent inner sheet. In this process, the deformation of the upper sheet was relaxed by contacting with the inner sheet, and then the strain on the outer surface reduced. Although softening around a weld nugget occurred by heating in the conventional welded joint, work-hardening occurred in the hemmed joint. The joint strength was investigated and then the peel strength of the hemmed sheets was about a half of the welded one. It was found that the hemming process with the pre-bent inner sheet was effective for joining ultra-high strength steel sheets with low ductility.

Improvement of Joint Strength by Arc Spot Welding in High Strength Steel Sheets

2020 ◽  
Vol 89 (3) ◽  
pp. 190-193
Author(s):  
Seiji FURUSAKO ◽  
Masatoshi TOKUNAGA ◽  
Shinji KODAMA ◽  
Masanori YASUYAMA
Keyword(s):  
High Strength Steel ◽  
Spot Welding ◽  
Joint Strength ◽  
High Strength ◽  
Steel Sheets
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