Under high temperature conditions, the hot-dip galvanized layer will undergo a series of changes, which will affect its performance as follows: Appearance changes: High temperature may cause the color of the hot-dip galvanized layer to change, turning yellow, gray, or even black. This is because high temperatures cause the zinc layer to oxidize, generating different zinc oxides, which in turn affect the appearance and color of the coating.
Changes in microstructure: The microstructure of the hot-dip galvanized layer changes at high temperatures. Zinc grains grow, and grain boundaries become blurred. This change in organizational structure alters the mechanical properties of the zinc layer, typically resulting in decreased hardness and increased toughness.
Changes in corrosion resistance: Generally speaking, within a certain temperature range, the corrosion rate of hot-dip galvanized layers will accelerate as the temperature increases. This is because high temperatures accelerate the chemical reaction between zinc and oxygen, moisture, and other corrosive media in the air, and may also damage the passivation film on the zinc layer surface, reducing its protective effect on the substrate. When the temperature exceeds a certain limit, the zinc layer may peel or flake off, further losing its protective properties.

1. The environment must be dry and well-ventilated. This is the primary condition for storage. Galvanized steel sheets must never be exposed to rain or moisture. Once water droplets condense on the surface and remain damp for a long time, the zinc layer will undergo a chemical reaction, forming a white corrosion product, also known as "white rust." White rust not only affects the appearance but can also reduce the thickness of the galvanized layer and weaken its corrosion resistance in severe cases. Therefore, ideally, they should be stored in a closed, well-ventilated indoor warehouse. If outdoor storage is necessary, the storage must be tightly covered with a good waterproof tarpaulin, and care should be taken to ensure that the tarpaulin does not fit tightly against the surface of the sheet to prevent condensation from directly contacting the sheet surface.

2. The bottom must be elevated for isolation. Galvanized steel sheets must never be stacked directly on the ground. Ground moisture (dampness) is one of the main culprits of rust. When stacking, the sheets must be elevated using sleepers, rubber mats, or special padding strips. It is generally recommended to raise the sheets at least 20 cm off the ground to ensure air circulation at the bottom of the sheets and to remove moisture.

Transportation Process:
1. Prevent Physical Damage
Although the galvanized layer is hard, it also has flexibility. If it is not securely fixed during transportation, the sheets will slide and rub against each other, causing scratches or abrasions that are difficult to repair. Therefore, it must be securely tied during loading to prevent displacement during long-distance travel. At the same time, "rough handling" is strictly prohibited during loading and unloading. Do not throw the sheets or allow the sharp teeth of forklifts to hit the edges, as this may cause deformation or damage to the zinc layer on the ends.

2. Avoid Contact with Corrosive Substances
During transportation, special care must be taken not to mix galvanized sheets with corrosive or strongly absorbent chemicals such as acids, alkalis, salts, and cement. If these substances leak or generate dust that adheres to the surface of the galvanized sheets, it will quickly cause severe localized corrosion, resulting in permanent defects.

The price differences you observe are usually not simply a matter of "selling low and high," but are determined by multiple real cost factors.

Some suppliers attract orders with low prices first, then add costs in the following ways:
Ocean Freight Surcharges: The quoted price may be FOB, but a higher-priced freight forwarder is specified, or the buyer is passed on the increased freight costs.

Destination Port Charges: Low invoices lead to customs clearance problems, or unprofessional customs declarations result in penalties.

Order Amendment/Expedited Delivery Fees: During the later stages of production, suppliers demand additional fees to ensure timely delivery under the pretext of "rising raw material prices" or "environmental protection restrictions."
Document Discrepancies: Deliberately creating discrepancies to delay payment or demand price reductions.

Don't just look at the unit price. Request the following from the supplier:
Based on the material (specific grade, standard), whether VAT is included, packaging details (photos or videos), payment method and prepayment percentage, supporting documentation for claims in case of quality issues or delays.

CSMC's self-operated products all use a clearly broken-down pricing method. If you purchase through our platform, we will ensure that you receive the actual product matching the quoted price.

Price differences among Chinese suppliers are a normal market phenomenon; the key is to understand the value behind the price. We recommend that you prioritize suppliers with reasonable prices, transparent pricing breakdowns, and the willingness to accept third-party verification.