Causes and Prevention Methods of Oil Stains and Watermarks on Aluminum Profiles

Characteristics of oil stains on aluminum profiles surface:

If oil stains on aluminum profiles are not cleaned before aging, watermarks will appear on the aluminum surface after aging. After oxidation, dark spots with a certain depth will form.

Causes of oil marks on the surface of aluminum profiles:

1. Cutting oil stains from the finished product saw remain on both ends of the aluminum profile, and gloves are not clean or even have graphite dust when handling the material;

2. When stretching the aluminum profile, dirty gloves are used to handle the material for too long, and saw marks are not removed;

3. Dirty gloves during intermediate sorting leave "marks";

4. Oil leakage from extrusion equipment tools (overhead crane, lifting straps).

Methods to remove oil marks from aluminum profiles:

1. During the aluminum production process, when handling aluminum alloy profiles, gloves must be clean, and any oil stains should be wiped off promptly;

2. When stretching aluminum materials, handle them appropriately;

3. Separate gloves should be used for handling and lifting materials, stretching, and inserting rods;4. Pay attention to oil leaks in equipment and tools, and ensure that papers, strips, slings, etc., are clean.

Characteristics reflected by watermarks on the surface of aluminum profiles:

Silver-gray wet stains appear on the surface of aluminum profiles, and the stains fade or disappear as the strength of oxide-alkali washing of the aluminum alloy profiles increases.

Causes of Water Marks on Aluminum Profiles:

Local water exposure or rain on the surface of aluminum profiles can penetrate the fine pores of the quenching oxidation layer on the profile's surface into the aluminum substrate, forming aluminum hydroxide. The visibility of the marks depends on the duration of water exposure. If the water contains impurities (such as salts or nitrites), corrosion spots may form.

Method to remove watermarks from aluminum profiles:

Aluminum profiles that get wet should be wiped dry immediately. They must be dried before aging. If conditions allow, appropriately extend the alkali cleaning time and increase the thickness of the oxide layer.

Summary:

As long as oil stains and water stains are wiped clean in time before the aluminum profiles attract dust, there will be no oil marks or watermarks. The key lies in cultivating good operational habits and quality awareness; there is nothing else. There was an incident in the past where a low-level quality accident occurred: using oily paper as a lining for the profiles resulted in the profiles being covered with oil marks after self-aging.