Introduction:
Hot-dip galvanize can vary in appearance, and therefore usability, as a function of spangle size,
zinc composition, mechanical treatment, and chemical or oiling treatments. Marketplace problems can develop because the customer finds the appearance is different than expected, or changes due to darkening, water staining, or field handling marks. These and other issues are reviewed, along with actions that can be taken to control them and minimize problems with end users.
Prepainted Galvanized Steel Coil or Sheet:
1. Standard:ASTM A653,JIS G3312,
2. Size:Thickness:0.13-1.0mm, Width:40mm-1250mm.
3. Zinc coating: 30-275g/m2;Top Coating:15-25microns; Back Coating:7-15microns
4. Colour:According to Customer's Sample or RAL Color Card.
5. Package:Standard Export Package
6.Application: Produciton of Corrugatedd Steel Sheets,Decoration, Construction.
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.
A typical hot-dip galvanizing line operates as follows:
Steel is cleaned using a caustic solution. This removes oil/grease, dirt, and paint.
The caustic cleaning solution is rinsed off.
The steel is pickled in an acidic solution to remove mill scale.
The pickling solution is rinsed off.
A flux, often zinc ammonium chloride is applied to the steel to inhibit oxidation of the cleaned surface upon exposure to air. The flux is allowed to dry on the steel and aids in the process of the liquid zinc wetting and adhering to the steel.
The steel is dipped into the molten zinc bath and held there until the temperature of the steel equilibrates with that of the bath.
The steel is cooled in a quench tank to reduce its temperature and inhibit undesirable reactions of the newly formed coating with the atmosphere.
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 Pilling 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. 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.
Packaging for Hot Dip Galvanized Steel Strip:
Shanghai Metal Products are packed and labeled according to the regulations and customer's requests. Great care is taken to avoid any damage which might be caused during storage or transportation. In addition, clear labels are tagged on the outside of the packages for easy identification of the product I. D. and quality information.
Application of Hot Dip Galvanized Steel Strip:
1.Construction and building: roofing; ventilating duct; handrail; partition panel,etc.
2.Further processing: coating base plate
3.Electric appliance: Refrigerator; washing machine; recorder; microwave, etc.
FAQ
What is Galvanized Steel?
There are two typical galvanizing ways to obtain a zinc coating: hot dip galvanizing and electrogalvanizing. Hot dip galvanizing is the process that steel is immersed into molten zinc bath to get a zinc coating surface. This not only helps protect steel from rust and corrosion, but also gives the steel a shiny attractive appearance. Electrogalvanizing is the process that uses electrolysis to coat the steel with zinc, which is neither cost-effective nor environmentally friendly. It is hardly to find electrogalvanized steel in our lives nowadays.
What are advantages of galvanized steel?
Because of permanently and successive zinc/iron alloy layers, galvanized steel offers many benefits than traditional steels.
>>Corrosion Resistance: the zinc coating surface protects the base steel not only by providing barrier to corrosion elements, but also by the sacrificial nature of the coating. Galvanized steel often remains in working order with little maintenance for 40 years or more.
>>Excellent Surface Appearance
>>Formability: it can be simply bend to parts with deep drawing requirements.
>>Paintability: it can be painted with different colors.
>>Weldability: it is accepted various welding practices.
What are disadvantages of galvanized steel?
In spite of many benefits, galvanized steel is not always an ideal choice. Galvanized steel cannot be used underground without properly covered, which can be inconvenient for many jobs.
Where do we use galvanized steel?
It is primarily used in the construction industry, such as roofing, wall cladding, and support beams. It is also used in the automotive industry, due to its enhanced paintability, weldability and corrosion resistance. Moreover, it is an essential material for white goods application, such as refrigerators, air-conditioners, washers, microwaves, vending machines and audio visual systems.
