| Autor: |
Kim, Ji-Young, Yoon, Seung-Chae, Kim, Hye-Jin, Lee, Myoung-Gyu |
| Zdroj: |
International Journal of Precision Engineering & Manufacturing; Feb2023, Vol. 24 Issue 2, p173-186, 14p |
| Abstrakt: |
A cold trimming technology reduces the process time and product cost compared to the common laser trimming method in hot stamping process. However, high stress concentration during the cold trimming can lead to quality defects such as premature cracking. Moreover, the defects may cause critical delayed fracture under hydrogen environment. In this study, experimental and numerical investigation are provided to understand the effect of cold trimming method on the surface quality and hydrogen induced delayed fracture of a hot stamped high strength steel. Specimens with different clearances, tool geometries, and process conditions are considered along with different trimming methods. The new trimming processes are the process division and double punching methods, which are suggested to overcome the drawback of the conventional single punching method. The experiments show that the sheared surface profile is mainly dependent on the trimming clearance, while the hydrogen embrittlement (or its resultant delayed fracture) is dominantly affected by the stress state of the trimmed surface. Especially, significant improvement in the hydrogen delayed fracture of hot stamped steel can be achieved by introducing the double punch method. This study suggests that the double punching can be a potential trimming method as an alternative to the laser trimming by reducing the cost and process time in producing the hot stamped automotive parts. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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