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Aluminum causes stripes surface
Dec 07, 2016

Stripes are many kinds of extruded aluminum profile, form factor, and more complex, listed below are some common fringe causes and solutions.

And friction pattern

Mould after each light die extrusion, Ridge is not one-to-one, a light weight.
The main reason
In the extrusion process, profiles out of the die hole moments work tightly together, constitute dry friction pair under a hot, and the work is divided into two areas--adhesion and sliding area. In the area of adhesion, metal particles from at least two aspects of the role: friction and shear forces. When adhesion by metal particles in the region controlled by the friction is greater than the shear forces, metal particles will stick to the adhesive on the work surface and surface scratches formed friction marks.

1, adjust the working out of the angle α, so that within the scope of their at-1 ° ~-3 °, which can reduce adhesion height, reduced friction in the area, increasing the slide area;
2, efficient die nitriding treatment, keep the mold surface hardness HV900 above work with sulfur reduced adhesion of the surface area friction, reduces friction and lines.

Second, tissue stripes

Analysis on main reasons
Ingot casting is uneven, segregation, under the skin of ingot has more serious defects, ingot of uniform treatment is not sufficient, in the subsequent extrusion process leads to uneven surface composition, so as to keep the profile oxidizing coloring ability are not identical, form stripes.

1, reasonable implementation of the casting process, eliminate or mitigate organizational segregation;
2, ingot surface wagon;
3, careful ingot homogenizing.

Third, metal-bright-line
Shining performance in the oxidized white material, in most cases for straight strip width and uncertain, the stripe is in the colouring oxides light strips.

Analysis on main reasons Due to friction or deformation Metal flow occur when severe, local temperature will rise very high metal, Metal flow asymmetry can also cause grain broken violently, and recrystallization, resulting in changes in the Organization, in the subsequent oxidation leads to surface longitudinal light stripes, colorization which profiles are not painted or rendered light stripe.

1, reasonable design of mold structures;
2 mold machining to work with transition to prevent drop;
3, to ensure that model bridge is teardrop-shaped, eliminating the edges.

Four, bonding stripes
Bonding stripes, also known as weld, through long, light grey in the oxidation of white material, colouring in the light.

Analysis on main reasons
1 mold diversion holes too small;
Room 2, welding depth, with no guarantee of a sufficient pressure;
3, extrusion die when welding aluminum indoor materials are in short supply;
4, the extrusion process is unreasonable, improper lubrication.

1, reasonable design of mold structures;
2, pay attention to harmonization of extrusion temperature and extrusion speed;
3, minimize lubricated or not lubricated.