Dynamic study of the compression strength of cuboid steel specimens cut of Hardox 450 sheet

conference proceedings

English

An experimental analysis was performed to determine the high-speed compressive strength of cuboid steel specimens including material anisotropy using a split Hopkinson bar technique. The specimens were fabricated from a high-strength steel Hardox 450 metal sheet with a thickness of 5 mm. To study material anisotropy, specimens were taken along 0°, 45°, and 90° relative to the rolling direction. A low positive strain rate sensitivity was observed from the onset of yielding over all tested strain rates in all directions. This fact is very important for manufacturing process because higher strain rates are more common in manufacturing processes, since quasi-static strain rates are use very rarely encountered in metal sheet forming, e.g. hydroforming or superplastic forming. If the design of the tool and the selection of a suitable machine (press, die hammer) were made using the values obtained during quasistatic tests, fatal damage to both the tool and the machine could occur. During testing at a quasi- static strain rate increase in engineering stress with increase in specimen orientation was observed. However, as the strain rate in-crease this phenomenon starts to disappear. This process can be observed in the growth of the yield stress. At quasi-static strain rates, the difference in specimen with orientations 0° and 90° relatively to the rolling direction is about 32 %. However, in the case of the highest strain rate, the difference is only about 1 %. These results are good for manufacturing processes, especially in sheet metal forming.

Hardox 450 steel; metal sheet plate; anisotropy; split Hopkinson pressure bar test; high strain rate; upsetting test

JOPEK, M.; SVOBODA, P.; SOBCZYK, K.; JANISZEWSKI, J.; KRUSZKA L.; MIKULSKI, E.

9. 9. 2024

ETH Zurich

Zurich

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