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Generation and avoidance of oil marks and watermarks on the surface of aluminum profiles

2022-03-31

Characteristic reflection of oil mark on aluminum profile surface;

If the oil stains of aluminum profiles are not cleaned before aging, watermarks will be produced on the surface of aluminum profiles after aging. After oxidation, the spots are dark and high.

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Causes of oil marks on the surface of aluminum profiles;

1. The oil stains of finished products are left at both ends of aluminum profiles, and gloves are not clean or even sticky with graphite ash when materials are moved (lifted);

2. When the aluminum profile is stretched, the gloves are too dirty, and the gloves are not removed by sawing;

3. Gloves are dirty and leave a "mark" during material handling in the middle;

4. Oil leakage from extrusion equipment and tools (traveling crane, lifting belt).

Removal method of oil mark on aluminum profile surface:

1, material management in the process of aluminum production, gloves should be clean when carrying materials, and oil stains should be wiped off in time;

2. When stretching aluminum materials, take materials properly;

3, material management, gloves when lifting and moving materials and stretching materials, gloves when adding rods should be separated;

4, equipment, tools, pay attention to oil leakage, pad paper straps, etc. should be clean.

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Characteristic reflection of aluminum profile surface watermark;

Silver-gray wet spots appear on the surface of aluminum profiles, and aluminum profiles fade or disappear with the increase of the strength of oxidizing alkali washing.

Causes of aluminum profile surface watermark:

The surface of aluminum profile is soaked in water and rain locally, and it penetrates into the aluminum matrix through the tiny holes of the quenching oxide layer on the surface of the profile, forming trihydroxyboehmite, which becomes bright and light with the water retention time. If there are impurities (salt, nitrous acid, etc.) in the water, corrosion spots will be produced.

Removal method of aluminum profile surface watermark:

Water-soaked aluminum profiles should be dried immediately and before aging. If conditions permit, the alkali cleaning time and oxide film thickness should be appropriately increased.

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