Galvanized corrugated iron or steel (colloquially corrugated iron (close to universal), wriggly tin (taken from English military slang), pailing (in Caribbean language), corrugated metal sheets (in North America) and sometimes abbreviated CGI ) are building materials consisting of lightweight galvanized steel sheets , Cold-rolled to produce a linear corrugated pattern in it. Although still popularly called "iron" in the UK, the material used is actually steel, and only vintage sheets are still left that are actually made of iron. Corrosion increases the flexural strength of the sheets in a direction perpendicular to the wrinkle, but not parallel to them. Usually each sheet is produced longer in a strong direction.
CGI is light and easy to transport. It is and is still widely used especially in rural and military buildings such as warehouses and water tanks. Its unique properties are used in the development of countries like Australia from the 1840s, and still help developing countries today.
Video Corrugated galvanised iron
History
CGI was discovered in the 1820s in England by Henry Robinson Palmer, architect and engineer at the London Dock Company. Originally made of wrought iron. Proven to be light, strong, corrosion resistant, and easy to move, and especially lent to prefabricated and improvised structures by semi-skilled workers. It soon became a common construction material in rural areas of the United States, Chile, New Zealand and Australia and then India, and in Australia and Chile also became (and remains) common roofing material even in urban areas. In Australia and New Zealand in particular have become part of the cultural identity, and the use of fashionable architecture has become commonplace. CGI is also widely used as a building material in African slums and informal settlements.
For roof purposes, the sheets are placed somewhat like tiles, with lateral overlaps of one and half wrinkles, and vertically overlap about 150 millimeters (5.9 inches), to provide waterproofing. CGI is also a common construction material for industrial buildings around the world.
Wrought Iron CGI was gradually replaced by mild steel from around the 1890s, and the CGI iron was no longer available but the common name has not changed. Galvanized sheets with simple wrinkles are also gradually removed by 55% Al-Zn coated steel or coated sheets of coils with complex profiles. CGI remains common.
Maps Corrugated galvanised iron
Today's wrinkle
Today the bumpy process is done using the roll forming process. This modern process is highly automated to achieve high productivity and low cost associated with labor. In the corrugated sheet process sheets are drawn from large rolls and through rolling dies that form wrinkles. After the metal sheet passes the roller automatically cut off to the desired length. The traditional form of corrugated material is rounded corrugated, but different dies form various shapes and sizes. Industrial buildings are often built and covered by trapezoidal sheet metal.
Many materials today undergo a wave process. The most common materials are iron alloys but can also reach stainless steels. Copper and aluminum are also used. Regular iron alloys are the most common due to price and availability. The common sizes of corrugated materials can range from very thin gauges (0.012 inches, 0.30 mm) to relatively thick gauges (0.1943 inches, 4.94 mm). Thicker or thinner gauges can also be produced.
Other materials such as plastic and fiberglass are also given a wavy look. Many applications available for this product include using it with metal sheets to allow light to penetrate below.
Fields and depth
The wrinkles are described in pitch (distance between two peaks) and depth (height from peak to base of trough). It is important for the pitch and depth to be sufficiently uniform, so that the sheets are easily stacked for transport, and overlap neatly when connecting two sheets. The pitch has ranged from 25 mm (1 inch) to 125 mm (5 inches). It was formerly common for CGI used for vertical walls to have a pitch and a shorter depth than a CGI roof. This short-pitched material is sometimes called "wavy" instead of "wavy". But today, almost all CGI produced have the same pitch 3 inches (76 mm).
Echo
Flapping your hands or flicking one's fingers while standing next to a perpendicular sheet of corrugated iron (for example, on a fence) will produce a high-pitched echo with a pitch that falls quickly. This is because of the echo sequence of adjacent wrinkles.
If sound runs at 344 meters per second (1,130Ã, ft/s) and wavy irons have a wavelength (pitch) of 3 inches (76 mm) this would produce an echo with the maximum wavelength of that sequence, corresponding to 4500 Hz or more (about C above A on standard pianos). The first part of the echo will have a much higher tone because the impulse of an iron sound almost opposite to the bell will arrive almost simultaneously.
Corrosion
Although galvanization inhibits corrosion of steel, oiling is unavoidable, especially in marine areas - where salt water drives rust - and areas where local rainfall is acidic. Rusty steel roofs can last for years, especially if the sheets are covered by a layer of paint.
See also
- Chattel House
- Metal roof
- Nissen hut
- Tin Tabernacle
References
External links
- The Heritage Roof in Victoria, Australia (PDF, 181 kB)
- Corrugated Metal Roof & amp; Paneling
Source of the article : Wikipedia
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