Plättchen-Biegeversuch nach VDA 238-100∗

Abstract

KurzfassungZur Ermittlung der Versagensanfälligkeit von metallischen Werkstoffen bei Biege-Umformprozessen sowie von Kennwerten zur numerischen Simulation des Verformungsverhaltens dient der sogenannte Plättchen-Biegeversuch. Als Kennwert dient der beim Anriss der Probe herrschende Biegewinkel, der in der Regel aus dem aufgenommenen Stempelweg und der Geometrie der Prüfanordnung rechnerisch ermittelt wird. Bei ThyssenKrupp Steel Europe ist hierzu ein neuartiges optisches Winkelmesssystem im Einsatz, das zeitlich synchronisiert mit dem Kraft-Weg-Verlauf der Maschine den Biegewinkel kontinuierlich und direkt an der Probe bestimmt. Durch den Vergleich berechneter und gemessener Biegewinkelverläufe wird gezeigt, dass insbesondere bei Biegewinkeln über 90° deutliche Unterschiede in den Prüfergebnissen auftreten.

A Hot‐Stamped Medium‐Mn Steel with Superior Strength–Ductility–Bendability Combination and Thin Oxidation Layer

“…[28,29] The tensile properties were measured on the specimens with gauge length of 25 mm and gauge width of 6.25 mm according to the ASTM-E8 standard. [18] Tensile specimens were machined with the longitudinal axis parallel to the hot rolling direction. Tensile tests were performed using a SHIMADZU AG-X plus 100 kN testing machine (room temperature, crosshead speed 2 mm min À1 ).…”

“…The three-point bending angle was calculated using the punch displacement at which the maximum punch load was reached and unloaded according to the detailed method in refs. [18,31]. For comparison, the three-point bending angle of a commercial hot-stamped 22MnB5 steel without baking was tested according to the VDA 238-100 standard.…”

“…Three‐point bending behaviors of the steels were measured according to the VDA 238‐100 standard. [ 18 ] The size of the three‐point bending specimens was 60 mm × 60 mm × 1.4 mm. Three‐point bending tests were conducted on a tensile machine at room temperature.…”

“…At present, the three‐point bending test according to VDA 238‐100 standard is widely accepted to assess the plane strain bendability of hot‐stamped steels. [ 18 ] Recent studies found that both the volume fraction and mechanical stability of RA had influence on the three‐point bending behaviors of the newly developed Cr and Si alloyed hot‐stamped steels containing RA. [ 19 ] According to refs.…”

Hydrogen Embrittlement Evaluation and Prediction in Press‐Hardened Steels

“…The bending angle can be calculated from the displacement of the loading punch or by a manual postmeasurement. [ 127 ] Recently, this method has been extended to examine the HE effects on coated PHS. In the case of AlSi‐coated and bare 35MnB5 PHS, their HE susceptibility was analyzed by comparing the bending angles and the number and morphology of surface cracks ( Figure 9 ).…”