Process
The process of hot-dip galvanizing results in a metallurgical bond between zinc and steel with a series of distinct iron-zinc alloys. The resulting coated steel can be used in much the same way as uncoated. Galvanized steel can be welded; however, one must exercise caution around the resulting zinc fumes. Galvanized steel is suitable for high-temperature applications of up to 392°F (200°C). The use of galvanized steel at temperatures above this will result in peeling of the zinc at the intermetallic layer. Electrogalvanized sheet steel is often used in automotive manufacturing to enhance the corrosion performance of exterior body panels, this is however a completely different process.
Lead is often added to the molten zinc bath to improve the fluidity of the bath (thus limiting excess zinc on the dipped product by improved drainage properties), helps prevent floating dross, makes dross recycling easier and protects the kettle from uneven heat distribution from the burners. Lead is either added to primary Z1 Grade Zinc or already contained in used secondary zinc. A third, declining method is to use low Z5 Grade Zinc.
Steel strip can be hot-dip galvanized in a continuous line. Hot-dip galvanized steel strip (also sometimes loosely referred to as galvanized iron) is extensively used for applications requiring the strength of steel combined with the resistance to corrosion of zinc. Applications include: roofing and walling, safety barriers, handrails, consumer appliances and automotive body parts. One common use is in metal pails. Galvanised steel is also used in most heating and cooling duct systems in buildings
Individual metal articles, such as steel girders or wrought iron gates, can be hot-dip galvanized by a process called batch galvanizing. Other modern techniques have largely replaced hot-dip for these sorts of roles. This includes electrogalvanizing, which deposits the layer of zinc from an aqueous electrolyte by electroplating, forming a thinner and much stronger bond.
Read more about this topic: Hot-dip Galvanizing
Famous quotes containing the word process:
“Every modern male has, lying at the bottom of his psyche, a large, primitive being covered with hair down to his feet. Making contact with this Wild Man is the step the Eighties male or the Nineties male has yet to take. That bucketing-out process has yet to begin in our contemporary culture.”
—Robert Bly (b. 1926)
“Interior design is a travesty of the architectural process and a frightening condemnation of the credulity, helplessness and gullibility of the most formidable consumersthe rich.”
—Stephen Bayley (b. 1951)
“A process of genocide is being carried out before the eyes of the world.”
—Pope John Paul II (b. 1920)