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.

Seamless steel pipes have very high strength. Due to the use of high-precision rolling and heat treatment technology in the manufacturing process, seamless steel pipes have uniform wall thickness and no internal gaps, resulting in very high tensile and compressive strength. This high strength enables seamless steel pipes to withstand greater pressure and tension, and they are not easily deformed or broken, thus performing excellently in various complex environments.

Secondly, seamless steel pipes are extremely durable. Because it undergoes multiple quality inspections and controls during its manufacturing process, seamless steel pipes have very stable quality and excellent properties such as corrosion resistance, wear resistance, and high temperature resistance. This makes seamless steel pipes have a longer service life than ordinary steel pipes, and they can maintain good performance and appearance even after long-term use.

The strength of seamless steel pipes is mainly due to their unique production process and high-quality raw materials.

Unique manufacturing process: The manufacturing process of seamless steel pipes is complex and meticulous, with no welding seams produced throughout the process. This makes the overall structure of the steel pipe more complete and stable, greatly improving its compressive strength. In addition, through processes such as hot rolling and cold drawing, the material of the steel pipe has been optimized, and its strength and toughness have been significantly improved.

High-quality raw materials: Seamless steel pipes are usually made of high-quality steel, which has excellent mechanical properties. By combining the characteristics of seamless steel pipe production technology, the strength and durability of the product can be further improved.