Analysis of the main reasons: As the friction or deformation of the metal flow is extremely severe, the local temperature of the metal will rise very high. In addition, the uneven flow of the metal will lead to severe crushing of the crystal grains, and then recrystallization will occur, resulting in changes in the organization. Subsequent oxidation treatment results in longitudinal bright streaks on the surface of the profile, which results in the profile not being painted or showing light-colored stripes.
1, rational design mold structure;
2, mold processing should pay attention to the transition of the work belt, to prevent the emergence of work with a gap;
3, to ensure that the bridge is a drop-shaped bridge, eliminating corners.