About steel grades
Now it is the most commonly used, such as the TDC51 grade produced by Baosteel, the yield strength is between 260-320Mpa, and the tensile strength is between 350-400Mpa. Compared with structural steel, its yield strength ratio is slightly higher.
about width
The delivery accuracy of steel coils in all countries in the world is a positive tolerance, that is, the actual delivery width ≥ the nominal width at the time of ordering. The control of these widths is generally considered when the steel plate is cold-rolled, because the subsequent galvanizing and color coating processes will affect the corrosion resistance of the edge if the trimming process is performed. But if the positive tolerance of the steel plate is too large, it will exceed the feeding limit of the forming machine. According to experience, it is more appropriate to control it at 0-5mm.
about thickness
The thickness of Ppgi Color Coated Sheets from various manufacturers has different meanings.
The thickness marked on the label of the color-coated steel coil is sometimes the thickness of the substrate, some is the thickness of the substrate + the thickness of the coating, and some is the thickness of the substrate + the thickness of the coating + the thickness of the coating.
Baosteel currently adopts the substrate thickness + coating thickness (excluding color coating). This method of thickness calculation is suitable for building designers, because the strength of color coating is low. Considering the design margin and safety The sexual aspect should not be taken into account. In the same way, in terms of delivery thickness tolerance, Baosteel has always followed the positive tolerance delivery. In this way, although the processing area per ton of steel is reduced, the safety of the building is guaranteed in the end. Steel plate thinning must be carried out under the condition of strength improvement.
About the coating
The commonly used coatings for architectural Ppgi Color Coated Sheets are hot-dip galvanized and hot-dip galvanized. For Ppgi Color Coated Sheets, there is not much difference in the application fields of the two substrates. In a relatively acidic environment, the galvanized substrate is a better choice. For use in humid and alkaline environments, the advantages of the galvanized substrate’s incision corrosion resistance are reflected.
As for the thickness of the coating, the general requirements for roof panels and exterior wall panels are hot-dip galvanizing ≥ 180g/m 2 (about 26μm), galvanized ≥ 100g/m 2 (about 27μm), and the use environment is in a heavy industrial area Or at the seaside, relevant foreign associations have minimum galvanizing requirements, such as ECCA norms and Australian standards require galvanized layer weight ≥ 275g/m 2 (about 38μm), galvanized ≥ 150g/m 2 (about 40μm).
About the type of coating
The commonly used topcoats for coil coatings include polyester (PE), polyurethane (PU), silicon-modified polyester (SMP), fluorocarbon (PVDF), high weather-resistant polyester (HDP), primers and backcoats. The most common varieties are epoxy (EP), polyester (PE), polyurethane (PU) and so on.
About Coating Color and Gloss
The choice of color is mainly to consider the matching with the surrounding environment and the hobby of the owner, but from the perspective of use technology, light color has strong heat reflection ability and small contrast after powdering of the coating film. If it is cleaned and maintained properly, the service life will be longer. will be more beautiful. For gloss, in the outdoor use of color-coated panels, loss of light is the earliest phenomenon, especially for high-gloss products, the initial loss of light will be very fast. When the glossiness drops to about 20, it will last for a long time. This phenomenon will appear after several months of use. Therefore, the color-coated panels for outdoor buildings are generally low-gloss.
About Coating Thickness
Microscopically speaking, the coating is a porous organization. Water in the air and corrosive media (chloride ions, etc.) will invade through the weak part of the coating, causing corrosion under the film, and then the coating will blister and peel off. In addition, even with the same coating thickness, the secondary coating is denser than the primary coating. According to foreign reports and related corrosion test results, the front coating can effectively prevent the intrusion of corrosive media if it is more than 20 μm. PVDF products require thicker coating films. The requirements for the back coating depend on the application. The sandwich panel only requires one layer of primer that can be bonded, while the formed steel plate also requires two layers of coating due to the indoor corrosion environment, with a thickness of at least 10 μm.