Why is the Surface of Galvanized Angle Steel Rough?

Galvanized angle steel has the characteristics of good corrosion resistance and beautiful appearance. It is widely used in: curtain wall materials, power towers, communication towers, shelf construction, railways, highway protection, street light poles, marine components, construction steel structural components, substation ancillary equipment, Light industry, etc.

Galvanized angle steel can be divided into hot-dip galvanized angle steel and cold-dip galvanized angle steel according to process classification. Commonly seen in the market is hot-dip galvanized angle steel. Cold-dip galvanized angle steel generally needs to be processed by cold plating according to user needs. According to the side length, it can be divided into galvanized equal angle steel and galvanized unequal angle steel. Hot-dip galvanizing is divided into blow plating and rack plating.

The surface quality of galvanized angle steel is stipulated in the standard, and it is generally required that there should be no defects harmful to use, such as delamination, scarring, cracks, etc.

The allowable range of angle steel geometric shape deviation is also stipulated in the standard, which generally includes curvature, side width, side thickness, vertex angle, theoretical weight, etc., and stipulates that the angle steel must not have significant torsion.

Characteristics of hot-dip galvanized angle steel

(1) The galvanized layer of hot-dip galvanized angle steel and the steel are metallurgically bonded and integrated into one body. Its tensile strength is more than twice that of ordinary steel and can be used instead of iron plates;

(2) Hot-dip galvanized angle steel has a long service life: generally more than 30 years, and requires no maintenance under normal use;

(3) Hot-dip galvanized angle steel has extremely strong anti-corrosion and anti-rust capabilities, and its corrosion resistance is far better than ordinary steel;

(4) The strength and toughness of hot-dip galvanized angle steel are much higher than ordinary steel, and can be used to make heavy machinery equipment, mechanical accessories and various heavy vehicles;

(5) Hot-dip galvanized angle steel is light in weight and easy to transport. Hot-dip galvanizing is formed by melting zinc powder into liquid at a high temperature of 900°C and then cooling it.

(6) Hot-dip galvanized angle steel can be 100% recycled and complies with national environmental protection policies;

(7) Hot-dip galvanized angle steel has good processability.

Reasons for the rough surface of galvanized angle steel

(1) "Over-pickling" occurs during pre-plating treatment

Over-pickling "makes the surface of the steel rough or produces bean marks, which is also one of the reasons why the surface of the workpiece is rough after hot-dip galvanizing.

(2) The temperature of the zinc solution is too high or the zinc immersion time is too long.

When the temperature of the zinc liquid is too high, the zinc immersion time is too long, or due to the influence of the angle steel composition and the Sandelin effect, excessive or uneven formation of the Zn-Fe alloy phase will also cause surface roughness. The thicker the galvanized layer, the surface The easier it is to appear rough. The hot-dip galvanized angle steel cools slowly after being taken out of the zinc liquid, or the steel section is too thick, or the angle steel is stacked immediately after hot-dip galvanizing without isolation, etc., the surface roughness will also appear.

(3) The composition or surface conditions of the steel selected for angle steel manufacturing

In fact, the smoothness and roughness of the surface of the galvanized layer are relative. Different from the "continuous hot-dip galvanizing" of steel plates, steel pipes or steel wires, hot-dip galvanizing of steel angles belongs to the batch hot-dip galvanizing process, and the galvanized layer is not gas-dip galvanized. Knife blowing. If the surface of the steel used in hot-dip galvanized angle steel is originally rough and uneven, with rust pits or obvious rolling stripes, after the hot-dip galvanizing is completed, the surface will generally not be smoother than before.

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