What is the standard for galvanized coils?

29 Apr.,2024

 

Hot-dip galvanization - Wikipedia

Process of coating iron or steel with molten zinc

If you want to learn more, please visit our website hot rolled galvanized steel coil suppliers.

Galvanised hand rail Crystalline surface of a hot-dip galvanized handrail, known as "spangle" Protective effect: completely rusted letter box mounted to a hot-dip galvanized wall

Hot-dip galvanization is a form of galvanization. It is the process of coating iron and steel with zinc, which alloys with the surface of the base metal when immersing the metal in a bath of molten zinc at a temperature of around 450 °C (842 °F). When exposed to the atmosphere, the pure zinc (Zn) reacts with oxygen (O2) to form zinc oxide (ZnO), which further reacts with carbon dioxide (CO2) to form zinc carbonate (ZnCO3), a usually dull grey, fairly strong material that protects the steel underneath from further corrosion in many circumstances. Galvanized steel is widely used in applications where corrosion resistance is needed without the cost of stainless steel, and is considered superior in terms of cost and life-cycle. It can be identified by the crystallization patterning on the surface (often called a "spangle").[1]

Galvanized steel can be welded; however, one must exercise caution around the resulting toxic zinc fumes. Galvanized fumes are released when the galvanized metal reaches a certain temperature. This temperature varies by the galvanization process used. In long-term, continuous exposure, the recommended maximum temperature for hot-dip galvanized steel is 200 °C (392 °F), according to the American Galvanizers Association. The use of galvanized steel at temperatures above this will result in peeling of the zinc at the inter-metallic layer[citation needed]. 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 which tends to achieve lower coating thicknesses of zinc.

Like other corrosion protection systems, galvanizing protects steel by acting as a barrier between steel and the atmosphere. However, zinc is a more electropositive (active) metal in comparison to steel. This is a unique characteristic for galvanizing, which means that when a galvanized coating is damaged and steel is exposed to the atmosphere, zinc can continue to protect steel through galvanic corrosion (often within an annulus of 5 mm, above which electron transfer rate decreases).

Process

[

edit

]

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:[2]

  • 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), help prevent floating dross, make dross recycling easier and protect the kettle from uneven heat distribution from the burners. Environmental regulations in the United States disapprove of lead in the kettle bath. 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.[3]

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, such as 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.

History

[

edit

]

In 1742, French chemist Paul Jacques Malouin described a method of coating iron by dipping it in molten zinc in a presentation to the French Royal Academy.

In 1772, Luigi Galvani (Italy), for whom galvanizing was named, discovered the electrochemical process that takes place between metals during an experiment with frog legs.

In 1801, Alessandro Volta furthered the research on galvanizing when he discovered the electro-potential between two metals, creating a corrosion cell.

In 1836, French chemist Stanislas Sorel obtained a patent for a method of coating iron with zinc, after first cleaning it with 9% sulfuric acid (H2SO4) and fluxing it with ammonium chloride (NH4Cl).

Specification

[

edit

]

A hot-dip galvanized coating is relatively easier and cheaper to specify than an organic paint coating of equivalent corrosion protection performance. The British, European and International standard for hot-dip galvanizing is BS EN ISO 1461, which specifies a minimum coating thickness to be applied to steel in relation to the steels section thickness e.g. a steel fabrication with a section size thicker than 6 mm shall have a minimum galvanized coating thickness of 85 µm.

Further performance and design information for galvanizing can be found in BS EN ISO 14713-1 and BS EN ISO 14713-2. The durability performance of a galvanized coating depends solely on the corrosion rate of the environment in which it is placed. Corrosion rates for different environments can be found in BS EN ISO 14713-1, where typical corrosion rates are given, along with a description of the environment in which the steel would be used.

See also

[

edit

]

References

[

edit

]

For more information, please visit Hot Dipped Galvanized Coil.

Galvanized Steel Coils as per ASTM A 653/A 653M

Galvanized steel coils are a vital component in various industries due to their exceptional corrosion resistance and durability. This article provides an overview of galvanized steel coils as per ASTM A 653A 653M, specifically focusing on the Z180 and Z275 specifications. We will delve into the hot-dip galvanization process, explore the applications of galvanized steel coils in different industries, highlight the advantages they offer, and discuss important considerations when selecting the right coils for specific needs. By the end, you will understand the significance of galvanized steel coils in numerous hot-dip galvanized applications and the benefits they bring to the table.

The Significance of Galvanized Steel Coils in Industrial Applications

Galvanized steel coils are highly valued in various industries due to their exceptional durability and corrosion resistance. They are commonly used in construction, automotive, and manufacturing sectors, where protection against rust and corrosion is crucial. Galvanised steel coils also offer excellent formability, enabling them to be shaped into different products and structures with ease.

ASTM A 653A 653M: An Overview of the Standard

Understanding ASTM A 653A 653M

ASTM A 653A 653M is a standard specification for hot-dip galvanized steel coils. It sets the requirements for the composition and quality of the zinc coating to ensure consistent performance and durability. This standard is widely recognized and used in the industry to ensure the reliability and consistency of galvanised steel coils.

Key Features and Requirements of ASTM A 653A 653M

ASTM A 653A 653M specifies the coating weight, adhesion, and other properties of the zinc coating on galvanized steel coils. It also outlines the testing methods and acceptance criteria for evaluating the quality of the coating. By adhering to this standard, manufacturers can ensure the durability and performance of galvanised steel coils in various applications.

Understanding Hot-dip Galvanization Process

The Basics of Hot-dip Galvanization

Hot-dip galvanization is a process in which steel coils are immersed in a bath of molten zinc to form a protective coating. The steel coils are thoroughly cleaned and then dipped into the molten zinc bath, allowing the zinc to bond with the surface of the steel. This process creates a layer of zinc that acts as a barrier, protecting the steel from corrosion.

Steps Involved in the Hot-dip Galvanization Process

The hot-dip galvanization process involves several steps. First, the steel coils are cleaned to remove any dirt, oil, or oxide layers. Next, the coils are dipped into a flux solution to remove any remaining oxides and provide a clean surface for the zinc coating. The coils are then immersed in the molten zinc bath, where the zinc adheres to the steel surface. Finally, the coated coils are cooled and inspected to ensure the quality of the zinc coating.

Z180 and Z275 Galvanized Steel Coils: Key Specifications

Differentiating Z180 and Z275 Galvanized Steel Coils

Z180 and Z275 refer to specific coating weights of zinc on galvanized steel coils. Z180 indicates a coating weight of 180 grams per square meter, while Z275 indicates a coating weight of 275 grams per square meter. The higher the coating weight, the greater the protection against corrosion.

Understanding the Significance of Z180 and Z275 Specifications

The Z180 and Z275 specifications play a crucial role in determining the performance and durability of galvanised steel coils. These specifications indicate the thickness of the zinc coating, which directly affects the corrosion resistance of the steel. Choosing the appropriate coating weight is important to ensure that the galvanised steel coils provide reliable protection against rust and corrosion in specific applications.

Overall, galvanised steel coils, manufactured in compliance with the ASTM A 653A 653M standard and featuring various coating weights such as Z180 and Z275, offer excellent corrosion resistance and durability. These coils find extensive use in diverse industries, making them a reliable choice for applications requiring long-lasting protection against rust and corrosion.

Applications of Galvanized Steel Coils

Galvanized Steel Coils in Construction and Infrastructure

When it comes to construction and infrastructure, galvanized steel coils are like the unsung heroes. They are used in a wide range of applications such as roofing, siding, gutters, and even structural support. The galvanized coating on these coils provides excellent protection against corrosion, making them perfect for outdoor use. So, the next time you marvel at a sturdy building or a robust bridge, remember that galvanized steel coils played a vital role in making it possible.

Galvanized Steel Coils in the Automotive Industry

You might not think about it, but galvanized steel coils are present in your car or any vehicle you hop into. The automotive industry relies on these coils for various components, including body panels, chassis, and even exhaust systems. The galvanized coating provides exceptional protection against rust, ensuring that your vehicle remains in top-notch condition for a longer time. So, the next time you hit the road, give credit to the little galvanised steel coils keeping your ride intact.

Galvanized Steel Coils in Manufacturing and Fabrication

Manufacturing and fabrication wouldn’t be the same without the trusty galvanized steel coils. These coils find their way into a plethora of products, ranging from appliances to electrical enclosures. With their corrosion-resistant properties, galvanized steel coils ensure that these products can withstand the test of time, even in harsh environments. So, the next time you use your trusty toaster or admire a sturdy metal cabinet, remember that galvanized steel coils are the unsung heroes behind them.

Advantages and Benefits of Using Galvanized Steel Coils

Enhanced Corrosion Resistance

Nobody likes dealing with rusty parts or structures falling apart due to corrosion. That’s where galvanized steel coils come to the rescue. Their galvanised coating creates an impenetrable barrier against moisture and other corrosive elements, ensuring that your materials stay intact and corrosion-free.

Durability and Longevity

If you’re looking for materials that can stand the test of time, galvanised steel coils fit the bill perfectly. The galvanization process adds a layer of protection that enhances the durability and longevity of the steel. So, whether it’s a building, a vehicle, or any other product, using galvanized steel coils means you’re investing in longevity.

Cost-effectiveness

Saving money is always a plus, and galvanized steel coils can help you achieve that. Their superior corrosion resistance and longevity translate into reduced maintenance and replacement costs in the long run. So, while initial costs may be slightly higher, the cost-effectiveness of galvanized steel coils becomes evident over time.

Considerations for Selecting the Right Galvanized Steel Coils

Factors to Consider for Specific Applications

When choosing galvanized steel coils, it is essential to consider the specific requirements of your application. Factors like coating thickness, steel grade, and even the environment in which the product will be used should be considered. So, make sure to do your homework and select the right galvanized steel coils that best suit your needs.

Quality and Certification Requirements

Quality matters, especially when it comes to galvanized steel coils. Ensure that the coils you choose meet the necessary quality standards and certifications. Look out for reputable manufacturers who follow industry regulations and provide the necessary documentation. Trustworthy suppliers will have no problem providing you with the certifications you need.

 

Be Responsible for the Environment. Use DANA STEEL products. We use Sustainable Manufacturing Practices and have a very low Carbon Footprint. Click HERE to know more. 

About Us

DANA Steel (www.danasteel.com) is an ISO 9001:2015 certified company, with rich experience of around three decades, we have always thrived hard in order to bring revolutionary changes to the steel industry; We have our state-of-the-art Cold Rolling Mill (CRM Complex) Situated in DIC (Dubai Industrial City) we proudly manufacture our products in Dubai, UAE.

Our market extends over a wide demographic as we export over products to around 50 countries including countries from the Indian subcontinent (Bangladesh, India, Nepal); Southeast Asian countries (Indonesia, Thailand, Vietnam); Middle-East countries including members of GCC (GCC-Saudi Arabia, Bahrain, Kuwait, Jordan, and Oman) (Riyadh, Dammam, Khobar, Jeddah, Yanbu, Jubail Ibri, Salalah, Muscat, Sohar, Nizwa, Barka). We also have our markets extended to Africa (Djibouti) and South America. With our constant commitment to customer contentment, we can provide competitive prices and faster shipment to all our valuable clients.

Feel free to contact in case of any enquiry. Listed below are the mediums through which you can reach us out!

WhatsApp – +971507983153

Tel – 0097142217273

Email – info@danagroups.com / info@danasteel.com

For more Hot Dipped Galvanized Steel Coilsinformation, please contact us. We will provide professional answers.