Metal Galvanized Roofing Sheets is manufactured from hot-dipped galvanized steel sheet and other metal sheets, which are rolled and then cold-formulated into various corrugated shapes. Depending upon the intended surface condition, they are classified into flat whole-face products, small flat spoons, long flat spoons and bright full-face products. Flat and long-flat products are best suited for exterior use, where as bright and short-flat products suit better domestic applications. These products are also known as corrugated zinc-coated metal sheets, galvanized steel wool, galvanized zinc coated metal sheets, galvanized steel wool coated metal sheets, coated steel wool, corrugated steel wool and galvanized metal wool.
Galvanizing refers to the action of giving a metal its specific electrical charge by subjecting it to an electrochemical process called galvanization. Prior to welding, the metal is exposed to an electrochemical gradient, wherein the initial galvanized steel sheet is exposed to an environmentally benign zinc solution, with an effective thickness of about 0.2 millimeters. The galvanized steel sheet is then charged with zinc, with the resulting mixture serving as the electrode.
With this electrode, the metal galvanized roofing sheet is subjected to alternating current that is provided when the two electrodes are bonded together. The galvanic coating on the steel sheet serves as a shield for the coated steel bars against external corrosion. Once bonded, these galvanized steel sheets undergo heating treatment, and their electrical conductivity is increased. This increases the current carried by the metal galvanized roofing sheets, and consequently, their performance is enhanced too https://tonnamkim.com/inox-thep-khong-gi/.
The galvanized roofing sheet that experiences the heating treatment is subjected to fatigue testing, using a strain gauge to determine the amount of elongation or stress that the metal spangle experiences before, during and after the galvanizing process. During the testing, the length of the galvanized roofing spangle that is to be tested is placed on the spindle at a distance equal to half the span of the spindle, while the current is applied to the galvanized roofing sheet. The galvanized steel sheet is then stretched at a constant tension, so that the galvanized roofing spangle is extended as far as possible. After stretching, the stretched metal spangle is then tested using a mathematical expectation evaluation. Using this calculation, the mechanical properties of the metal spangle are mathematically derived, and the theoretical weight of the metal spangle is then calculated as a function of the galvanized roofing material.
Another test procedure is done to determine the elongation of the rolled edge of a galvanized sheet. This test is called half-rounding. In this test, a galvanized rolled edge of a galvanized metal roofing is placed on a rotary vane at an angle which is half the radius of the vane’s axis. The angle of rotation of the rotating vane against the galvanized edge of the rolled edge then determines the elongation of the galvanized edge.
One important property of the cold rolled steel sheet is its capability to resist corrosion when it comes in contact with natural occurring substances such as oil, grease or water. Because of its excellent resistance to corrosion, the coating is considered highly effective in the fight against corrosion. With its extreme durability, the china coating has found applications in virtually every industry.