What is hot-dip galvanizing of photovoltaic brackets?
The hot-dip galvanizing process is also called hot-dip galvanizing. It is to immerse the steel bracket after cleaning and activation in molten zinc liquid. Through the reaction and diffusion between iron and zinc, a zinc alloy coating with good adhesion is plated on the surface of the steel bracket to form a hot-dip galvanized bracket. It is a relatively stable and reliable steel surface treatment solution to resist environmental corrosion.
According to the national standard GBT13192-2002 for raw materials, the thickness of the attached zinc layer is determined. Generally, the thickness of the attached hot-dip galvanized photovoltaic bracket is between 63 and 86μm. The thickness of the traditional hot-dip galvanized bracket is generally greater than 2mm. For windy areas, the thickness reaches 2.5mm.
The process flow of hot-dip galvanizing of photovoltaic brackets is:

Process: degreasing → water washing → pickling → water washing → dipping and plating solvent → drying and preheating → hot-dip galvanizing → finishing → cooling → passivation → rinsing → drying → inspection
Among them, the hot-dip galvanizing link must control the zinc liquid temperature, immersion time and the speed of workpiece removal from the zinc liquid.
If the temperature is too low, the fluidity of the zinc liquid is poor, the coating is thick and uneven, and it is easy to produce sagging and poor appearance quality; if the temperature is high, the fluidity of the zinc liquid is good, the zinc liquid is easy to separate from the workpiece, reducing the occurrence of sagging and wrinkling, strong adhesion, thin coating, good appearance, and high production efficiency;

But if the temperature is too high, the workpiece and the zinc pot will suffer serious iron loss, a large amount of zinc slag will be produced, affecting the quality of the zinc immersion layer, zinc consumption is large, and even plating cannot be performed. At the same temperature, the immersion time is long and the coating is thick.

When the same thickness is required at different temperatures, high-temperature immersion takes a long time. In general, manufacturers use 450~470℃ and 0.5~1.5min to prevent high-temperature deformation of the workpiece and reduce zinc slag caused by iron loss.

Some factories use higher temperatures for large workpieces and cast iron parts, but avoid the temperature range of the peak iron loss. In order to improve the fluidity of the hot-dip plating solution at a lower temperature, prevent the coating from being too thick, and improve the appearance of the coating, 0.01%~0.02% pure aluminum is often added in small amounts and multiple times.

Process requirements Visual inspection of all hot-dip galvanized parts, its main surface should be smooth, no nodules, roughness and zinc thorns (if these zinc thorns will cause damage), no peeling, no leakage, no residual solvent slag, and no zinc nodules and zinc ash in the parts that may affect the use or corrosion resistance of hot-dip galvanized workpieces.

Advantages of hot-dip galvanized photovoltaic brackets:

1. Corrosion resistance: Zinc is the second largest element after aluminum and has good corrosion resistance. In marine environment, industrial atmosphere, soil and corrosive media, the zinc layer can effectively protect the photovoltaic bracket from corrosion.

2. Wear resistance: The galvanized layer has a high hardness and can resist the wear of the steel surface.

3. High temperature strength: The hot-dip galvanized layer can still maintain high strength and hardness at high temperatures, which is conducive to improving the service life of the photovoltaic bracket in high temperature environments.

4. Tensile strength: The zinc layer can significantly improve the tensile strength of the photovoltaic bracket, which is conducive to improving the stability under external force.

5. High aesthetics: The galvanized layer is silvery white and has good gloss.

6. Simple process, energy saving and environmental protection: The hot-dip galvanizing process is relatively simple, with a short production cycle, low cost, less waste generated in the process, and little impact on the environment. It is an environmentally friendly surface treatment method.
What is galvanized aluminum-magnesium photovoltaic bracket?

Aluminum-magnesium-zinc plating is to add aluminum, magnesium and a trace amount of silicon to the zinc plating layer. While silicon improves the processability of the aluminum-containing plating layer, it further improves the corrosion inhibition effect of the anti-corrosion layer through the composite effect with magnesium. The product has the characteristics of self-healing of the incision, and the metal surface is also chlorine-resistant, alkali-resistant, wear-resistant and corrosion-resistant. Therefore, it can better cope with the harsh environment of deserts, tidal flats, saline-alkali land and other regions.

Aluminum-magnesium-zinc plating technology has different anti-corrosion mechanisms in the plane part and cross-section part of the metal.
The mass fraction of metal elements in the plating layer is: 53% aluminum, 43% zinc, 2% magnesium, 1.5% silicon and other elements. In the flat part of the metal, the parent material cuts off the contact between water and oxygen and the metal through the dense protective film formed on the surface of the plating layer, thereby inhibiting the corrosion rate.
In terms of technology, hot-dip galvanized brackets are made by punching, bending and punching ordinary steel plates to form steel brackets, and then transported to the factory for hot-dip galvanizing. The zinc-aluminum-magnesium bracket is directly made of steel strips coated with zinc-aluminum-magnesium coatings, cold-bending, deviation correction, fixed length and punching connection holes to form steel sections, and finally made into zinc-aluminum-magnesium brackets. It is made directly by the steel plant and directly processed by the bracket processing plant, which saves time and effort and guarantees quality.
Compared with hot-dip galvanized brackets, zinc-aluminum-magnesium brackets reduce the repeated logistics process in the middle and reduce certain costs.

Advantages of galvanized aluminum-magnesium photovoltaic brackets:

1. Corrosion resistance
The zinc-magnesium-aluminum coating has higher corrosion resistance than traditional galvanizing technology. In harsh climates and environments, the electrochemical reaction rate of the zinc-magnesium-aluminum coating is slower, and the corrosion products formed are more compact, so it can effectively extend the service life. According to tests, in terms of salt spray corrosion resistance, the zinc-magnesium-aluminum coating technology is more than 50% higher than the traditional galvanizing technology, and can reach more than 1,000 hours of salt spray test.

2. Thermal stability
Zinc-magnesium-aluminum coating has good thermal stability and can be used under high temperature conditions. After high-temperature steam cycle test, there is no obvious shedding phenomenon of zinc-magnesium-aluminum coating, and the surface coating integrity is good, indicating that zinc-magnesium-aluminum coating technology can be applied to industries and fields with high temperature environment requirements.

3. Plasticity of electrophoretic coating
Compared with other anti-corrosion coatings, zinc-magnesium-aluminum coating technology can better achieve the plasticity of electrophoretic coating. A layer of purple conversion film is formed on the surface of AI-Mg-Zn coating, which makes the coating have better adhesion and durability.

4. Lightweight and high strength
The products of zinc-magnesium-aluminum coating technology are lighter and stronger than traditional galvanizing technology. Because the film weight of zinc-magnesium-aluminum coating technology is lighter than that of traditional galvanizing technology, under the same thickness of film layer, the weight of the product is only 2/3 of the galvanized product, and the strength is higher than that of traditional galvanizing technology.