Fatigue strength of misaligned non-load-carrying cruciform joints made of ultra-high-strength steel

2020 ◽  
Vol 175 ◽  
pp. 106334
Author(s):  
A. Ahola ◽  
T. Björk
2021 ◽  
Vol 179 ◽  
pp. 106563 ◽  
Author(s):  
Tuomas Skriko ◽  
Kalle Lipiäinen ◽  
Antti Ahola ◽  
Heli Mettänen ◽  
Timo Björk

2020 ◽  
Vol 4 (2) ◽  
pp. 54 ◽  
Author(s):  
Ken-ichiro Mori

Shearing processes of high strength steel sheets increasingly applied to lightweight automobile parts were reviewed. With the increase in strength of the high strength steel sheets, shearing operations become hard. First, the sheared edge quality in shearing of high strength steel sheets and the effects on the formability and fatigue strength were shown. Next, ironing processes with a taper punch and a punched slug, a slight clearance punching with a punch having a small round corner and a thickening process of the sheared edge were explained as processes for improving the sheared edge quality. Finally, hydrogen-induced delayed fractures of cold-sheared ultra-high strength steel sheets and of hot-trimmed parts were evaluated.


2021 ◽  
Vol 228 ◽  
pp. 111544
Author(s):  
Kalle Lipiäinen ◽  
Antti Ahola ◽  
Tuomas Skriko ◽  
Timo Björk

2016 ◽  
Vol 716 ◽  
pp. 428-434 ◽  
Author(s):  
Yohei Abe ◽  
Ken-Ichiro Mori ◽  
Ryota Kosaka

The effect of the hole edge shape formed by a punching process including thickening on the fatigue strength of the hole of ultra-high strength steel sheets was investigated. The bending and tensile fatigue tests of the thickened hole edge were performed. For the bending fatigue strength, the high height of hole edge was effective because of high bending stiffness. Although the high tensile stiffness was important for the high tensile fatigue strength, the shape of hole edge was alternative. To increase both the bending and tensile fatigue strengths, a compressive process in rollover of hole edge was added for the thickened sheet having a high bending fatigue strength. It was found that the thickened and compressed hole edge of ultra-high strength steel sheet was effective in improving both the bending and tensile fatigue strengths.


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