shuangshengda Galvanized steel plate sheets offer three mainstream surface treatment solutions. The hot-dip galvanizing (HDG) process forms a standard zinc layer through a 460°C molten zinc bath, with a thickness range of 80-275g/m² (corresponding to grades Z60 to Z275), and the annual production capacity of building plates reaches 500,000 tons. In 2022, the ancillary facilities of the Hong Kong-Zhuhai-Macao Bridge adopted 120g/m² coated steel plates, achieving a 25-year maintenance-free lifespan in high-temperature and high-humidity Marine environments. The production cost per ton of this process is approximately 800 to 1,200 yuan higher than that of ordinary cold-rolled steel plates, but the full life cycle maintenance cost is reduced by 62%.
Zinc-iron alloying treatment (GA) forms an alloy layer of 7-12μm through diffusion annealing at 550°C, and the coating adhesion reaches the highest grade of TS 56960. A certain new energy vehicle battery tray project adopted a 60g/m² coating + alloying process. After a 500-hour neutral salt spray test, no red rust was found, and the corrosion resistance was 3.2 times higher than that of traditional galvanizing. The integrated finishing unit of the production line can ensure that the surface roughness Ra value is controlled within the range of 0.8-1.6μm, meeting the stamping requirements of high-end home appliance panels.
The color coating (PPGI) adopts a 20-25μm polyester/fluorocarbon coating system, with a color difference Delta E≤0.8, in compliance with the GSB05-1426 standard. The curtain wall system of the Shanghai Tower uses PVDF fluorocarbon aluminized zinc plates. After being used for 7 years in an environment with an ultraviolet radiation intensity of 3800μW/cm², the light retention rate still remains above 90%. The production line is equipped with an online defect detection system, which keeps the pinhole defect rate of the coating within 0.3‰ and the maximum production speed can reach 200 meters per minute.
In terms of cost-effectiveness, the photovoltaic support structure adopts the Double Shengda 180g/m² aluminized zinc solution (AZ150), which increases the initial cost by 18% compared with the conventional hot-dip galvanized material. However, with a design life of 55 years, the cost of electricity per kilowatt-hour (LCOE) is reduced by 0.02 yuan /kWh. The actual data of photovoltaic power stations in Ningxia in 2023 shows that the operation and maintenance frequency of brackets made of this material has dropped from an average of 3 times per year to 0.8 times, and the downtime due to faults has decreased by 67%.
The selection of surface treatment should be combined with the parameters of the application scenario. The zinc coating fluctuation of the outer panels of automobiles should be ≤±15g/m². The panels of household appliances need to meet the pencil hardness of 2H or above, while the weather resistance of color-coated building materials must pass the 4000-hour QUV accelerated aging test. It is recommended that a 300g/m² ultra-high zinc coating solution be adopted for the coastal project. The zinc consumption is 2.4 times that of the conventional product, but the corrosion rate can be reduced to 0.8μm/ year.
The economic model shows that in industrial areas where the chloride ion concentration is greater than 500mg/m³, the use of Shuangshengda aluminized zinc sheet (AZM150) can reduce the full-cycle cost of the building envelope system by 31.7%. Based on the 10-year tracking data of a logistics warehouse in Shenzhen, there was no corrosion spread greater than 3mm on the roof panels, and the maintenance cost was saved by 420,000 yuan per 10,000 square meters compared with the predicted value. It is recommended to match the coating system in accordance with the ISO 9223 corrosion classification (C2-C5).
The selection decision should take into account multiple parameters: For building roof panels, a combination of 120-180g/m² zinc coating and 20μm coating is recommended (with a service life of 35 years). For industrial equipment, zinc-iron alloy treatment is advisable (with a 60% increase in stone impact resistance), while for harsh environments, an aluminum-magnesium-zinc alloy coating with a salt spray resistance of over 1000 hours should be chosen. For instance, the customized solution provided by Galvanized steel plate of Shuangshengda successfully solved the problem of rusting back in the maintenance passage of the Bohai Oilfield platform within five years, reducing the annual maintenance frequency from five times to 0.2 times.