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Prepainted Galvanized Steel Coil-A Complete Buying Guide by Sunnyda.

Prepainted Galvanized Steel Coil process involves the galvanization of prepainted steel which refers to the application of zinc layer on steel surface for protective functions.

Galvanization is helpful in keeping the steel safe from corrosion and rust damages.

Prepainted galvalume steel coil, on the other hand, involves the combined coating of silicone, aluminum, and zinc metals for providing protection to the steel against oxidation.

The galvanization process of the steel sheet is then followed by the conversion of the sheet in the coil form.

The Prepainted Galvanized Steel Coil has a wide range of applications in building construction, electronic appliances, automobile construction, houseware manufacturing, etc.

Keep reading below to know more about the Prepainted Galvanized Steel Coil in detail.

1.What is a Prepainted Galvanized Steel Coil?
2.What are the Hot Dip Galvanizing Features of Prepainted Galvanized Steel Coil?
3.What is the Electro Galvanizing Features of Prepainted Galvanized Steel Coil?
4.What are the Specifications of a Prepainted Galvanized Steel Coil?
5.What are the Applications of a Prepainted Galvanized Steel Coil?
6.How does a Prepainted Galvanized Steel Coil Offer Resistance to Acid Rain?
7.Is Prepainted Galvanized Steel Coil UV Resistant?
8.Does Prepainted Galvanized Steel Coil Provide Resistance to Humid Heat?
9.How is Prepainted Galvanized Steel Coil Low-Temperature Resistant?
10.What Happens in the Annealing Stage of the Prepainted Galvanized Steel Coil Production?
11.How does the Coating Process of a Prepainted Galvanized Steel Coil Work?
12.Why is the Prepainted Galvanized Steel Coil Passed Through the Spangling Step?
13.How is the Prepainted Galvanized Steel Coil Chemically Treated?
14.What are the Mechanical Properties Required for Hot Rolled Base Metal in the Manufacturing of Prepainted Galvanized Steel Coil?
15.Which Mechanical Features Must be Present in the Cold Rolled Base Metal for Making Prepainted Galvanized Steel Coil?
16.What are the Purchasing Instructions for Prepainted Galvanized Steel Coil?
17.What is the Packing Criteria for a Prepainted Galvanized Steel Coil Shipping?
18.What is the Loading and Shipping Instruction for your Prepainted Galvanized Steel Coil?
19.What are the Maintenance Instructions for your Prepainted Galvanized Steel Coil?
20.Which Storage Instructions you Must Consider Regarding your Prepainted Galvanized Steel Coil?
21.What are Some Degreasing Instructions Related to a Prepainted Galvanized Steel Coil?
22.What are the Handling Guidelines for your Prepainted Galvanized Steel Coil?
23.What is the Best Treatment for Black Discoloration of your Prepainted Galvanized Steel Coil?
24.What are the Most Common Problems of Prepainted Galvanized Steel Coil?
25.How to Solve the Problems of your Prepainted Galvanized Steel Coil?
26.Conclusion

What is a Prepainted Galvanized Steel Coil?

Prepainted Galvanized Steel Coil is a coil produced by the coating of a metal sheet with paint which is then rolled to acquire the shape of a coil.

This prepainted steel coil is then passed through molten zinc to form Prepainted Galvanized Steel Coil.

Hot zinc perfectly adheres to the coil, which offers excellent corrosion resistance properties to the prepainted galvanized steel and increases its service life.

What are the Hot Dip Galvanizing Features of Prepainted Galvanized Steel Coil?

The hot-dip galvanizing features of a Prepainted Galvanized Steel Coil are:

• Zinc coating for adding a protective layer.

• Light coating to improve formability.

• Heavy coating for adding anti-corrosion properties.

• Alloy coating for increasing paint adhesion and heat resistance.

• Conversion coat application with chromate-free properties for improving ductility.

What are the Electro Galvanizing Features of Prepainted Galvanized Steel Coil?

The electro galvanizing features of Prepainted Galvanized Steel Coil include:

• Electroplating to form a smooth, uniform, and attractive outer surface.

• Light coating with compatible mechanical properties to bring weldability.

• Post-treatment with anti-fingerprint characteristics to enhance paintability and lubricity.

• Alloy coating for added corrosion resistance.

What are the Specifications of a Prepainted Galvanized Steel Coil?

The specifications of a Prepainted Galvanized Steel Coil include:

• High-quality RAL surface coating colors

• Single and double coating

• Export quality packaging

• Single and double drying

• Structural grade base metal

• Thickness ranges from 0.16mm to 1.2mm

• Width lies between 600mm to 1250mm

• The weight of the coil can be between 3 to 9 Tons

• The inside coil diameter is 508 or 610 mm

• The top paint coat is 15 to 25 μm thick

• The back coat is seven and a half μm thick

What are the Applications of a Prepainted Galvanized Steel Coil?

The Prepainted Galvanized Steel Coil has wide applications in:

• Household appliances

• Construction materials

• Automobile parts

• Agricultural industry

How does a Prepainted Galvanized Steel Coil Offer Resistance to Acid Rain?

Prepainted Galvanized Steel Coil offers great resistance to acid rain. The industrial environment contains a lot of pollutants and toxic emissions from different types of machinery.

These chemicals, when released to the outside environment, combine with rain to form acid rain.

When acid rain comes in contact with steel, it speeds up the process of corrosion, which results in surface damage.

A Prepainted Galvanized Steel Coil gives an extra layer to the steel and protects against acid rain.

If the galvanization process is not done properly, acid rain will penetrate through the paint, causing damage to the steel.

Is Prepainted Galvanized Steel Coil UV Resistant?

Ultraviolet rays are very strong and damage the paint layer leading to problems like discoloration, chalking degeneration, loss of shine, and peeling of the paint layer.

Galvanization helps Prepainted Galvanized Steel Coil to gain protection against harmful UV rays and keep the steel safe from UV exposure.

Does Prepainted Galvanized Steel Coil Provide Resistance to Humid Heat?

The paint coating is strongly affected by increasing levels of humidity in the environment. High-temperature levels are also damaging to the paint layer.

When the osmotic pressure in the ambient air rises, water vapors are formed. High vapor concentration allows the penetration of vapors in the paint layer.

This results in the degeneration of the paint coat, which further leads to corrosion problems.

As a result, bubble formation on the paint surface takes place and leads to peeling and scraping of the coat.

Prepainted Galvanized Steel Coil provides good resistance to humid heat as the result of galvanization benefits.

How is Prepainted Galvanized Steel Coil Low-Temperature Resistant?

Usually, paint layers can offer stable functioning when the temperature is more than zero degrees. In alpine environments, the temperature levels are lower than 20 to 40 degrees.

This temperature range is unfavorable for normal paint and results in the drying and cracking of the paint layer.

If the affected paint is kept at this temperature for a longer period of time, the paint layer will peel off completely from the steel surface.

This will kill the protective and aesthetic functions of the paint layer. Galvanization helps Prepainted Galvanized Steel Coil to gain efficient low-temperature resistance.

What Happens in the Annealing Stage of the Prepainted Galvanized Steel Coil Production?

In the annealing stage of the Prepainted Galvanized Steel Coil production, the steel is left for a specific time at a temperature higher than the temperature required for its recrystallization.

After this time is completed, the steel is left to cool. The time required for cooling varies with the metal type being annealed, that is, steel in this case, which is cooled at room temperature.

During the annealing process, the heat provided to the steel causes migration of the atoms present in the crystal lattice, which causes a reduction in the number of dislocation atoms.

This brings a change in the hardness and ductility of steel and results in its recrystallization once it is cooled.

The phase composition and size of the crystals vary with the time required for cooling and heating.

The reason why the Prepainted Galvanized Steel Coil undergoes annealing is to enhance its workability and improve toughness.

In this phase, the brittleness of steel is also reduced, bringing an increase in its mechanical and electrical properties.

How does the Coating Process of a Prepainted Galvanized Steel Coil Work?

For preventing re-oxidization from taking place, the steel is passed through a vacuum chamber after the completion of the annealing process.

The steel is then allowed to enter the molten bath, where it is coated with zinc in a rolling motion.

The purpose of this zinc coating step is to keep the steel protected from corrosion problems as zinc has high anti-corrosion properties.

The protection of zinc coating against corrosion is the result of the formation of adherent and dense corrosion byproducts on the contact of the zinc-coated metal with the air present in the environment.

These byproducts are also called zinc patina which protective layer for the steel.

There are different types of methods available for the application of zinc coats in the Prepainted Galvanized Steel Coil manufacturing industries.

To ensure that the suitable zinc coating has been applied to the steel, you must find out the extent of corrosion resistance required for your application and the degree of the environment’s corrosive properties.

The weight and thickness of the zinc coating should be managed accordingly to ensure the maximum functioning of the zinc coat.

The zinc-coated steel is then treated with high-pressure air for the removal of extra zinc and ensuring constant thickness.

The finally prepared steel sheet is left to cool before heading towards the next step.

Why is the Prepainted Galvanized Steel Coil Passed Through the Spangling Step?

Once the zinc coating process is completed, the steel is allowed to enter the spangling step.

Spangling is an aesthetic property of crystallites that results in the snowflaky or six-sided star appearance on the steel surface.

Spangling is beneficial in increasing the visual appeal of steel and also distributing the coating elements uniformly.

For the spangling step, the cooling temperature for the zinc coat must be lower than its melting point.

How is the Prepainted Galvanized Steel Coil Chemically Treated?

The chemical treatment of the galvanized steel is about treating steel with chemicals for increasing its paintability and corrosion resistance.

The four main categories of chemical treatments on the steel surface are:

Pickling

Pickling involves the removal of impurities with the help of acids. For this reason, processes like heat treatment at high temperatures and welding are carried out.

Etching is done on the surface to remove unprotected parts.

Mixtures formed as a result of mixing nitric acid and hydrochloric acid are most widely used for the pickling process because of their increased effectiveness for this process.

You can use these acids in the form of paste or gel. The pickling mixtures available commercially contain 8% hydrochloric acid and 25% nitric acid.

This mixture is used for etching the steel surface. As a result, the surface becomes rough and dull.

But one thing to keep in mind is that both these chemicals can be damaging for the health and environment if misused. So make sure to use these chemicals with proper care and precautions.

Passivation

Passivation is carried out for improving the chromium levels existing on the steel surface.

For passivation, chemicals that have strong oxidizing properties and acidic nature are used.

The most widely used chemical for passivation is nitric acid. In addition to nitric acid, passivation formulations also contain oxidizers, for example, sodium dichromate.

About 50% of the composition of passivation formulation is nitric acid. The remaining percentage is covered by the presence of an oxidizer.

In the case of steel chemical treatment, nitric acid does not cause any harm to the surface.

But if you intend to use it on mirror-polished surfaces, it would be better to carry out a patch test forest.

In steel passivation, the carbon steel contamination present on the surface is dissolved by treating it with nitric acid.

In addition to this, the sulfide inclusions are also dissolved, which end up breaking the steel surface.

The benefit of treating the surface with nitric acid is the increase in the surface chromium proportion.

Chelating

The chemical that helps in the removal of contaminants from the steel surface is known as chelating agents.

The chelating agents are known to possess chemical claws that help in the selective cleaning of the steel surface.

The main functional group present in most of the chelating agents is carboxylic acid. These chelating agents are most effective for tasks like cleaning, lubrication, and water softening.

But one thing to consider in the case of chelation treatment is to maintain the correct temperature and pH level for the chelating agent to provide the best results.

After the chelating process, make sure to rinse the vessels and pipes turbulently for maximum effectiveness.

Electropolishing

The process which involves electrochemical treatment for the removal of impurities is called electropolishing.

The benefits of this process are to provide smoothness and brightness to the steel surface.

The electropolishing treatment majorly involves the use of sulphuric and phosphoric acid in conjunction with keeping the current density high—this ensures maximum cleaning of the steel surface by removing metal and bringing smoothness.

The most beneficially affected areas for electropolishing are the round valleys and peaks. Electropolishing is also helpful in increasing the chromium levels at the steel surface.

It also results in enhancing the brightness and luster of the surface by bringing a 30% alteration in the roughness.

What are the Mechanical Properties Required for Hot Rolled Base Metal in the Manufacturing of Prepainted Galvanized Steel Coil?

The mechanical properties required for the hot-rolled base metal in the manufacturing of Prepainted Galvanized Steel Coil are:

• Good structural quality

• Excellent commercial quality

• Specific forming quality

• Suitable drawing quality

• High strength steel

• High stretch flange

• Low yield ratio steel

Which Mechanical Features Must be Present in the Cold Rolled Base Metal for Making Prepainted Galvanized Steel Coil?

The making of Prepainted Galvanized Steel Coil demands the presence of some major mechanical features, which are:

• Excellent structural quality

• Good commercial quality

• High forming ability

• Deep drawing ability

• Bake hardenability

What are the Purchasing Instructions for Prepainted Galvanized Steel Coil?

The purchasing instructions for Prepainted Galvanized Steel Coil include considering the following points:

Formability

The property of steel to complete plastic deformation without getting damaged

Paintability

The degree of adhesion formed between the steel surface and paint layer

Weldability

The ability of steel parts of forming connections for making a single sheet

Corrosion Resistance

The extent of showing resistance against the contact of steel surface with the humidity of the ambient air

What are the Packing Criteria for a Prepainted Galvanized Steel Coil Shipping?

The packing criteria for a Prepainted Galvanized Steel Coil are:

• Paper board core placement

• Waterproof paper wrapping

• Plastic film coating

• Guard sheet covering (on the outer as well as inner side)

• Using circle edge projector

• Packing finishing

What is the Loading and Shipping Instruction for your Prepainted Galvanized Steel Coil?

The loading and shipping instructions for your Prepainted Galvanized Steel Coil are:

• Using a 20′ container for loading and shipping purposes

• Adding maximum protective layers for preventing the Prepainted Galvanized Steel Coil from damage

• Covering in the wooden frame for safe transportation

• Maintain the appropriate temperature and humidity levels in the shipping vehicle

• Customizing special containers and frames for extra-large coils

What are the Maintenance Instructions for your Prepainted Galvanized Steel Coil?

The maintenance instructions for your Prepainted Galvanized Steel Coil are:

• The surface of the Prepainted Galvanized Steel Coil must be kept clean and free of dirt and dust.

• Only use recommended cleaning agents for the cleaning process.

• Do not keep the Prepainted Galvanized Steel Coil in a humid environment.

• Repaint if the paint coat starts peeling or scraping off.

• Keep the steel coil protected from high-temperature levels to avoid top coating damage.

• Make sure to carry out all the galvanization steps properly for maximum corrosion resistance.

Which Storage Instructions you Must Consider Regarding your Prepainted Galvanized Steel Coil?

The storage instructions you must consider regarding your Prepainted Galvanized Steel Coil include:

• As soon as you receive your package, see if there is any moisture content present in the packaging. If any moisture is detected, dry it out immediately.

• Store it in a moisture-free place to avoid contact with environmental oxygen that causes corrosion.

• Ensure that the package is not cracked or broken that can let allow moisture entry.

• Get the packaging repaired if found damaged.

• Do not put any heavy things on or around the Prepainted Galvanized Steel Coil to avoid dent formation.

What are Some Degreasing Instructions Related to a Prepainted Galvanized Steel Coil?

Some degreasing instructions related to a Prepainted Galvanized Steel Coil are:

• Lack of degreasing will lead to paint coating defects. The leftover dirt and dust will prevent uniform and smooth paint coating.

• Use a spray for the degreasing process to ensure a uniform supply of the degreasing material to the steel. Also, maintain a suitable distance when spraying to avoid paint damage.

• You can also dip the steel in a low alkaline or neutral agent to get uniform and fast coating results.

• Do not use strong alkaline agents for dipping purposes as they cause damage to the steel surface.

• Rinse properly once done with the degreasing steps.

What are the Handling Guidelines for your Prepainted Galvanized Steel Coil?

The handling guidelines for your Prepainted Galvanized Steel Coil include:

• Use gloves when handling the steel sheet as it has sharp edges, which can lead to skin damage.

• Make sure to keep the Prepainted Galvanized Steel Coil protected from scratches to avoid paint damage.

• Do not let oil stains form on the surface during the handling

• Lubricated sheets have slippery surfaces and, therefore, must be handled with extra care.

• Stack the piles carefully to ensure that the sheets don’t slide away.

What is the Best Treatment for Black Discoloration of your Prepainted Galvanized Steel Coil?

The best treatment for Black Discoloration of your Prepainted Galvanized Steel Coil involves an oil coating process.

Zinc surface when comes in direct contact with oxygen, a thin oxidized film is formed near its surface.

As a result, light is absorbed and reflected, ultimately leading to the blackening of the steel surface.

The storage environmental conditions play an essential role in deciding the time for surface blackening.

High humidity and temperature levels in the environment contribute to rapid blackening.

You can not avoid the blackening process completely but delay it for some time with the help of oil coating.

What are the Most Common Problems of Prepainted Galvanized Steel Coil?

Corrosion is the most common problem that usually occurs in the Prepainted Galvanized Steel Coil. There are three main things that result in corrosion problems are:

• The presence of an electrolyte

• The surface of steel being directly exposed to the environment

• The presence of an electron acceptor

How to Solve the Problems of your Prepainted Galvanized Steel Coil?

The conditions promoting Prepainted Galvanized Steel Coil corrosion must be avoided to prevent corrosion problems.

For this reason, appropriate steps are taken to solve corrosion problems. These steps are:

Building a Physical Barrier Between the Steel Surface and the Environment

Enamel or paint coating on the surface of the steel will act as a protective barrier between the exposed surface and the surrounding.

This reduces the chance of direct contact of the exposed steel surface with the environmental oxygen and water content, thus causing a decrease in the chances of corrosion and rusting of the steel surface.

Oxidized Coatings

The sacrificial coating is the process that involves coating the surface of steel with an oxidizing metal. Zinc is mostly used for coating the steel surface via the process of galvanization.

Zinc undergoes the process of oxidation when exposed directly to environmental oxygen. The alloy present undergoes reduction and gains cathodic properties as a result.

This helps in the corrosion inhibition of the steel.

Cathodic Protection

By conferring a continuous negative charge about the metal, you can keep it protected from corrosion problems. This process is known as cathodic protection.

For providing a continuous supply of negative charge to the surface, direct current is provided.

Cathodic protection has multiple applications, including providing protection to the underground pipes, fuel tanks, etc.

Anodization

In anodization, steel is allowed to buyers in a specific substance maintaining the appropriate electrochemical conditions for allowing the appearance of pores having a width of several nanometers uniformly throughout the steel’s oxide film.

The benefit of these pores is to allow the building up of the oxide film, which is thicker as compared to the passivation layer.

The oxide layer is also very tough and resilient to withstand extreme environmental conditions.

Anode Protection

Sacrificial anode protection involves protecting the steel surface from corrosion.

The anode layer formed itself undergoes corrosion on getting exposed to the ambient humidity and prevents the humidity from reaching out to the underneath surface.

But what you need to keep in mind is that this sacrificial anode protective layer must be replaced timely on undergoing corrosion for efficient protection of the steel.

Conclusion

The Prepainted Galvanized Steel Coil must undergo a proper galvanization process under professional observation for ensuring successful galvanization benefits.

To make steel withstand tough environmental conditions, including high-temperature levels, increasing environmental humidity, and oxidation problems, Prepainted Galvanized Steel Coil must be formed by galvanizing a protective layer on a prepainted steel surface.

FAQs of Prepainted Galvanized Steel Coil.

What are the Top Paint Layer Options of a Prepainted Galvanized Steel Coil?

The top paint layer options of a Prepainted Galvanized Steel Coil include polyurethane, polyester, polyvinylidene fluoride, silicone modified polyester, and high-density polyethylene coatings.

What are the Two Back Paint Coating Options Available for Prepainted Galvanized Steel Coil?

The two back paint coating options available for Prepainted Galvanized Steel Coil include modified polyester and epoxy coatings.

What are the Prime Paint Coating Choices in Prepainted Galvanized Steel Coil?

The prime paint coating choices in Prepainted Galvanized Steel Coil are epoxy, polyurethane, and polyester coatings.

What are the Substrates Available for Prepainted Galvanized Steel Coil Coating Process?

The most available substrates for Prepainted Galvanized Steel Coil process include cold rolled steel, hot-dipped galvanized, zinc alloy, aluminum, and galvalume substrates.

What are the Applications of Prepainted Galvanized Steel Coil in Mechanical Equipment?

Prepainted Galvanized Steel Coil has diverse applications in mechanical equipment, including communication equipment, electric cabinets, computer shells, electric boxes, etc.

Which Electrical Appliances Involve the Use of Prepainted Galvanized Steel Coil?

The electrical appliances involving the use of a Prepainted Galvanized Steel Coil are washing machines, dehumidifying machines, water heaters, ovens, refrigerators, video recorders, etc.

What are the Building Materials Requiring Prepainted Galvanized Steel Coil Applications?

The building materials requiring the use of Prepainted Galvanized Steel Coil applications include ceiling plates, floor plates, roofs, warehouses, walls, compartments, and balconies.

What are the Applications of a Prepainted Galvanized Steel Coil in the Transportation Industry?

The applications of a Prepainted Galvanized Steel Coil in the transportation industry are in the construction of oil tanks, internal automobile plates, and vehicle backseat plates, etc.

Which Agricultural Equipment Involves the Use of Prepainted Galvanized Steel Coil?

The agricultural equipment involving the use of Prepainted Galvanized Steel Coil are greenhouses, large barns, breeding utensils, storage rooms, agricultural drying machines, flume utensils, etc.

What are the Applications of Prepainted Galvanized Steel Coil in Furniture Manufacturing?

The applications of Prepainted Galvanized Steel Coil in furniture manufacturing include the making of automatic vending machines, office furniture, garage equipment, and recreation machines.

What are the Surface Options Available for Prepainted Galvanized Steel Coil Surfaces?

The surface options available for Prepainted Galvanized Steel Coil surfaces include chromate, dry, unoiled, and oiled surfaces.

How does the Corrosion Resistance of Galvalume Steel Coil Differ from that of the Prepainted Galvanized Steel Coil?

The corrosion resistance of a galvalume steel coil is higher (3 to 6 times) than that of the Prepainted Galvanized Steel Coil.

What Happens When the Prepainted Galvanized Steel Coil is Subjected to Extreme Bending?

Deep drawing or extreme bending of the Prepainted Galvanized Steel Coil results in the peeling or whitening of the film.

What are the Causes of Discoloration of Prepainted Galvanized Steel Coil?

The main causes of discoloration of Prepainted Galvanized Steel Coil are washing, degreasing, welding, using lubricating oil, and brazing.

What are the Instructions for Prepainted Galvanized Steel Coil Welding Process?

Nickel and brass mixture is used for Prepainted Galvanized Steel Coil welding at very high temperatures.

Which Processing Precautions you Must Consider in Prepainted Galvanized Steel Coil Processing?

There are some lubricating oils that result in the erosion of zinc. A patch test must be carried out before finalizing the suitable oil required for the Prepainted Galvanized Steel Coil processing.

What are the Instructions to Consider for the Prepainted Galvanized Steel Coil Painting Process?

All the dirt must be removed from the surface prior to beginning the Prepainted Galvanized Steel Coil painting process to ensure smooth and even paint coating.