The Study on the Hot Forging of a Extruded and Continuously Cast Al 6061

압출 및 연주 Al 6061 합금의 열간단조 특성 연구

Generally, forging process has been known to enhance most of the mechanical properties by developing the continuous metal flow across the forged stocks. However, we have found out that forging of Al 6061 did not always give the enhancement of the mechanical properties but the degradation of the original characteristics, especailly for a extruded Al 6061. There are several candidates for the culprit of this unfavorable phenomenon. We have been trying to clear out the cause of the mechanical degradation of the forged a extruded Al 6061. One of the most plausible causes seems to be that the particles containing Mn and/or Cr is coarsened and redistributed preferencially onto grain boundaries due to a repetitive exposure in an elevated temperature condition. On the other hand, a continuously cast Al 6061 did not show any strength degradation after a hot forging under the same process condition with the extruded Al 6061.