A feasible way to prevent Foshan galvanized sheets from embrittlement in advance
Galvanized steel sheets may become embrittled if they are used for too long or are not used for a long time. Why? Long-term construction or storage will inevitably be exposed to natural light. Embrittlement will occur after long-term direct exposure to light, which we cannot avoid, but we can usually avoid it in advance to reduce the rate of embrittlement, so what should we do?
The necessary condition for embrittlement or photochemical reaction of color-coated boards is that the components of the surface layer of the color-coated boards can digest and absorb radiant energy; secondly, when the radiation energy digested and absorbed by the molecular structure exceeds the bond energy of the molecular structure, the coating of the color-coated boards can dissolve. Because the light wavelength of the light source is shorter, the kinetic energy it contains is higher.
According to this basic theory, the embrittlement of color-coated boards in the atmospheric environment is caused by the molecular structure of the coating absorbing the kinetic energy of the ultraviolet band in natural light that is higher than the bond energy of its molecular structure, causing the molecular structure of the coating to dissolve. As the coating film becomes embrittled, the base material itself gradually disappears, and the surface layer of the coating gradually becomes rough and loses its luster. This loss of base material leaves relatively stable pigment objects, which remain on the surface of the coating film in the form of unbound powder. This process is called powdering.
Generally speaking, there are big differences in the anti-aging properties of polyester color-coated boards with different coating thicknesses. The anti-aging properties of thin-coated color-coated boards are weak, and the anti-aging properties of normal thickness coatings are relatively poor. The sex was good.
Therefore, relying on thinning of the coating to reduce the cost of color-coated plate products is not feasible and will inevitably lead to serious product quality problems. At the same time, it is also discussed from the side that the ordering contracts of foreign color-coated plate purchasers must clearly indicate the thickness of the coating plate. importance.
