Thank you for your trust and inquiry. We have received your detailed inquiry regarding the import of steel from China and would like to provide you with the following professional and clear import process:

Standard Import Process:
1. Inquiry and Quotation - You provide the specific product specifications, quantity, and target port for the stainless steel coils. We will provide you with a detailed quotation including all costs.
2. Confirmation and Payment - After both parties confirm the order, you will make payment according to the contract (usually a 30% deposit). We support secure payment methods such as T/T (telegraphic transfer) and L/C (letter of credit).
3. Production and Quality Inspection - We have our own steel inventory and support customized production. After the deposit is paid, the factory will arrange production. We fully support third-party inspections and warmly welcome you to visit our factory.
4. Booking and Shipment - After the goods are produced and pass quality inspection, we will work with the freight forwarder to arrange container loading, customs declaration, and obtain the bill of lading for you. We offer various trade terms such as FOB and CIF.
5. Customs Clearance and Cargo Collection - After the goods arrive at your destination port, you can complete the formalities and collect the goods smoothly with the complete set of customs clearance documents provided by us.

Key documents we provide include: commercial invoice, packing list, bill of lading, certificate of origin, quality certificate, and insurance policy (if applicable).

We have long-term, reliable shipping partners and can arrange door-to-door international logistics services. We promise to provide complete quality documentation and fully cooperate with any third-party organization you designate for pre-shipment inspection (PSI).

We understand that there may be concerns about importing from China for the first time. Please rest assured that we will act as your reliable partner and provide you with professional support throughout the process. We welcome you to provide your specific needs, and we will tailor the best import solution for you.

The core reasons for chalking/fading of color-coated steel sheets:
1. Raw material defects
Substrate problems: Rust or incomplete cleaning of the steel sheet surface (residual oil/impurities) leads to poor coating adhesion, making it prone to chalking and peeling.
Poor coating materials: Resin is not weather-resistant: Low-end polyester resin (PE) has weak UV resistance and is easily decomposed and chalked; Inferior pigments: Inorganic pigments have poor lightfastness (such as some red and yellow pigments), making them prone to fading.

2. Substandard Production Process
Insufficient Pretreatment: Incomplete degreasing, phosphating, or passivation results in weak adhesion between the substrate and coating; Uneven Coating Thickness: Too thin (≤15um) easily powders, too thick (>30um) easily cracks; Incomplete Curing: Insufficient baking temperature or time prevents sufficient resin cross-linking, reducing weather resistance.

3. Environmental Corrosion: UV Radiation: Long-term exposure leads to resin decomposition (powdering) and pigment oxidation (fading). Acid/Alkali/Salt Spray Corrosion: Industrial exhaust gases and coastal salt spray corrode the coating surface. Large Temperature and Humidity Differences: Repeated thermal expansion and contraction cause coating cracking, allowing moisture to penetrate and corrode the substrate.

Regular inspection of color-coated steel sheets is necessary to promptly detect and address issues such as coating peeling and corrosion, extending their service life. Regular cleaning of the color-coated steel sheet surface is also crucial to remove dust, dirt, and other contaminants, maintaining its appearance and weather resistance. At the same time, avoid using strong corrosive cleaning agents to prevent damage to the coating.

The powdering rate not only affects the aesthetics of color-coated steel sheets but also directly impacts their service life and performance.

The powdering rate of color-coated steel sheets refers to the degree to which the coating on the surface of color-coated steel sheets powders under certain conditions. Chalking refers to the phenomenon where fine powder appears on the surface of a coating, causing the coating to lose its gloss, change color, or even peel off. A higher powdering rate indicates a lower coating quality and a shorter service life.

Factors affecting the chalking rate of color-coated steel sheets:
1. Coating quality: The quality of the coating is a key factor affecting the chalking rate. High-quality coatings have better weather resistance, corrosion resistance and adhesion, and can effectively reduce chalking rate.
2. Construction process: The construction process of color-coated steel sheets will also affect the powdering rate. A proper construction process can ensure a uniform and dense coating, thereby improving the coating's durability.
3. Usage environment: The usage environment of color-coated steel sheets is also an important factor affecting the powdering rate. Harsh environments such as high temperature, high humidity, and strong ultraviolet radiation can accelerate the chalking process of the coating.

Generally speaking, the chalking rate of high-quality color-coated steel sheets should be below a certain value, and the specific value varies depending on different products and application scenarios. When purchasing color-coated steel sheets, attention should be paid to the product's chalking rate index, and products that meet industry standards should be selected.

The common problems can be roughly divided into three types: uneven coating, anti-corrosion agent dripping, and anti-corrosion agent bubbling.

1. Uneven Coating. The root cause of this problem is the uneven distribution of the corrosion inhibitor on the surface of the steel pipe. Some parts are coated too thickly, while others are coated too thinly or not at all. This results in areas where the coating is applied too thickly exceeding the standard thickness, leading to waste; while areas where the coating is applied too thinly or not at all will have reduced corrosion resistance, causing rust to form.

2. Corrosion Insulator Dripping. When corrosion inhibitors solidify on the surface of a steel pipe like water droplets, it is called corrosion inhibitor dripping. This phenomenon often does not directly affect the corrosion resistance and can still ensure that the steel pipe has a certain required corrosion resistance. However, from an aesthetic point of view, steel pipes with corrosion inhibitor dripping look dull and uneven, directly affecting the appearance of the steel pipe.

3. Corrosion Insulator Blistering. Air trapped in the corrosion inhibitor causes air bubbles to form in the coating of the steel pipe. These bubbles vary in size depending on the specifications of the steel pipe. The larger bubbles are shaped like the air bubbles on the protective covers of some home appliance remote controls; they will burst if you press down on them with a little force. The foaming phenomenon of corrosion inhibitors not only affects the appearance of steel pipes, making the entire surface of the steel pipe appear rough and uneven, but the breakage of bubbles will also reduce the standard coating thickness, reduce the anti-corrosion ability, and lead to rust in the steel pipe area where the bubbles are located.