Construction: Roofing, cladding, profiling, tiles, ceiling, Pre-engineered Buildings.

General industry: Pipes, enclosures for electrical equipment, HVAC system.

Appliances: Washing machines, tumble dryers, refrigerators.

Aluzinc is widely used in the field of roofs. Its excellent resistance to atmospheric oxidation can maintain color for a long time, and its excellent heat reflection has a good heat insulation effect on roofs.

Aluzinc’s natural glitter and good reflective properties are also common in the field of interior decoration ceilings. Aluzinc is non-flammable and does not release toxic substances.

The main production processes of the prepainted galvalume production line include pre-treatment process, coating process, and baking process.

Uncoiling – sewing – degreasing – chemical pretreatment – initial coating – initial coating baking – initial coating cooling – fine coating – fine coating baking – fine coating cooling – inspection – splitting – coiling

The end result is an aesthetically appealing, environmentally friendly, efficient, low-maintenance, corrosion-resistant, durable, and energy-saver steel. This kind of product is ideal for interior and exterior use in producing metal furniture, civil engineering, wall panels, architectural elements of the construction industry, decorative appearance, and roof coverings.

Substrate 

The primary material to produce organic coated steel is either cold rolled sheets without metallic coating or hot dip galvanized (with metallic coating) sheets. Cold-rolled substrate (for structural method) comes in Standard DIN 1623/09 and S215G grade while (for drawing method) is EN 10130 Standard and has a grade of DC01 and DC03. 

Galvanized substrate (for drawing use) comes in EN 10346 Standard and a grade of DX51D+Z, DX52D+Z, and DX53DZ and (for structural use) has S220GD+Z, S250GD+Z, S280GD+Z, S320GD+Z, and S350GD+Z. 

Galvanized and Galvalume are galvanized substrates that are popular in the metal siding and roofing industry. They are both ideal substrates for metal panels. The difference between them lies in how they are created and several factors.

Galvanized steel

The galvanized steel has a zinc alloy coating that is done through hot-dipping. It cleans the steel and then dips it into molten zinc. The process was discovered in the 17th century and was patented by Stanislas Sorel in 1836. This traditional way of coating produces malleable steel that can last up to 20 to 50+ years. 

The hardened zinc offers extra protection to the base material, allowing it to withstand corrosion, rust, dents, and nicks. Galvanized steel is widely used in the manufacturing, fabrication, and construction industries. 

Pros 

• Economical
• Longer lifespan in the right environment 

Cons

• More pricey than galvalume
• Susceptibility to red rust
• Use of “oil-can” paints may result in aesthetic distortion on the appearance of flat areas
• No self-healing characteristic
• No substrate warranty

Galvalume steel

This metal sheet is coated with 55% aluminum, 43.4% zinc, and 1.6 silicon. It was invented in 1972 by Bethlehem Steel and can last from 50 to 60+ years. The unique coating of the material is perfect for wall, trim, roof, and accent works. It is also suitable for building applications in high-temperature regions, hurricane zones, and other locations with snowfall or high rain conditions.

Pros

• Economical and reasonably priced
• Has 2x to 4x corrosion resistance
• Comes with a warranty on substrates
• Has self-healing ability from red rusting at the edges 

Cons

• “Oil-can” paint does not adhere well and can create waviness or aesthetic distortion to the appearance
• Degrade more quickly during direct contact with concrete, lumber, brick, or iron materials

Organic coating systems

The primary ingredients in the organic coating system come from synthetic carbon-enriched compounds or natural (vegetable or animal) matter. The cohesive and solid coatings deliver additive finishes on the base steel material. They can be found in varnishes, paints, and lacquers.

The coating system refers to the coating applications on the material’s TDE and reverses sides. The top side or the outside of the coil is usually applied with rust, corrosion, and UV-resistant coatings, while the reverse side has layers that help to withstand storage and handling.

Basic coating types

• Primer or the priming coat: The purpose of primer is to provide an inter-coat adhesion between the topcoat and the substrate and generally make the coating system resistant to corrosion. The type of primer depends on the overcoat, application, environment, desired appearance, overall functionality, and thickness of the steel.
• Topcoat or finishing coat: The uppermost or final coating is applied on top of the primer. It is exposed to the elements of the outdoor environment, and its primary function is to protect the steel from corrosion. It also provides the material’s decorative and aesthetic appearance, including its color tone, texture, gloss, and other special effects. The ingredients for the topcoat are comprised of pigments, organic polymers, solvents, and additives. 
• Backcoat or backing coat: It is the coating of the reverse side of the sheet, which is typically for decorative purposes only. However, it also doubles up as a protective element of the inside panel. It can be applied with or without a primer. Primer application increases its thickness and better corrosion resistance. 

Zincalume steel was designed for harsh conditions and can be used for many purposes, including exterior building cladding, roofing and walling, and general fabrication. Zincalume can also be used in various structural applications, including racking, shelving, and flooring, in addition to light industrial buildings, garages, sheds, and carports.

Zincalume was created in 1976 and has since been improved under extensive laboratory and exposure testing to satisfy the client’s needs. After over two decades of research and innovation, BlueScope’s premium zinc/aluminum alloy coated steel, Zincalume, was launched in 2013 to be the industry’s standard for longevity and corrosion resistance.

ZN/AL Coating Technology: How does it work?

The ZN/AL Coating Technology displays a more intricate coating structure with two distinct layers. The zinc-rich layer acts as excellent sacrificial protection to the steel. In contrast, the aluminum-rich layer creates a durable barrier to impede further corrosion and activates the metal coating.

Zinc and aluminum in Zincalume result in a long-lasting coating that is resistant to corrosion and remains in good condition even when exposed to harsh environments.

Advantages of Zincalume Steel

Zinc and aluminum in Zincalume result in a coating with excellent forming capabilities. It has a lifespan longer than other materials, and its weathering resistance makes it ideal for use in outdoor applications. Zinc-aluminum coating also has an attractive appearance that is similar to stainless steel.

Corrosion Protection

Zincalume’s steel roof sheets and wall claddings come in various elegant profiles. Zincalume has a zinc/aluminum alloy coating that provides up to four times the corrosion resistance of galvanized steel.

Outstanding Forming Capabilities

Zincalume has a covering made of 55 percent aluminum, 43.5 percent zinc, and 1.5 percent silicon. It comes in high-strength grades and has outstanding forming capabilities. Additionally, it offers a perfect surface for applying the tried-and-true BlueScope painting method.

Greater Longevity

Zincalume steel was created to enhance the conventional performance of galvanized iron by combining zinc and aluminum in an alloy coating. As a result, Zincalume can last up to four times longer than regular galvanized steel.

Climate Resistance

Zincalume steel provides better resistance to weathering and surface marking, which makes it ideal for outdoor applications, thanks to BlueScope’s comprehensive research and development effort.

Vibrant Appearance

Zincalume steel provides a vibrant appearance due to its optimized combination of Aluminum and Zinc coating. It can also last longer because its passivation technology maintains the material’s radiance.

Residential ZINCALUME® Warranty

A 10-year residential warranty backs Zincalume for fascia and gutter downpipes and a 15-year residential warranty for wall cladding and roofing, so you can rest assured that your investment is protected for years to come.

Zincalume vs. Colorbond

Colorbond and Zincalume are made from steel sheets coated in zinc and aluminum.

The most notable difference between them is that Colorbond can be painted, while Zincalume cannot. It means that Colorbond will look like any other painted surface on your home, while Zincalume will always look metallic grey or silver.

The zinc-aluminum alloy used in Zincalume is more environmentally sustainable than the copper alloy used in Colorbond. Zincalume has a higher corrosion resistance than Colorbond, meaning it can stand up to the elements better, even in harsh conditions like coastal areas. It’s also more weather resistant and won’t fade, so you don’t have to worry about your house looking old or worn down over time. Zincalume is also less expensive than Colorbond.

Zincalume vs. Galvanized

Zincalume and traditional galvanized steel are used for roofing and other outdoor applications. While both coatings protect against rust, they differ in their coating and durability.

Galvanised metal is a type of metal that has been coated with zinc to prevent corrosion. Zincalume is a galvanized coated metal made of zinc and aluminum with a high-quality paint finish that gives it a more attractive look while protecting the metal from rust.

Zincalume is more durable and lasts more than 20 years, while galvanized steel lasts only about five years. Zincalume lasts longer than conventional galvanizes because it has an additional layer of protection against rusting or corrosion.

The Zinc Aluminum-Magnesium coated steel is a new product in the global steel trading industry. It is a result of various extensive steel manufacturing researches done to enable steelmakers to produce coated steel that is better than galvanized steel. 

This type of coated steel is a highly improved version of a corrosion-resistant steel plate which is made mostly of zinc (Zn), combined with a set amount of aluminum (Al) and magnesium (Mg). ZAM coated steels are widely used in different types of construction and can be formed in any kind of steel parts or shape. 

Comparison of corrosion resistance with galvanized steel

Galvanizing is a production method in which steel or iron is applied with a zinc coating to provide protection against corrosion or rusting. This technique, most especially the hot-dip galvanizing method, is widely used in manufacturing steel products.

NIPPON STEEL Corporation, however, with its goal to become the best steelmaker worldwide, has paved the way in manufacturing a better quality steel sheet product with its ZAM® coated steel. This product is better in all aspects than galvanized steel because of its higher corrosion resistance, cost and time efficiency, and more.

ZAM® coated steel sheets outperform galvanized and hot-dip zinc with 5% Al coated steel sheets in terms of red rust resistance. To prove this, ZAM products underwent outdoor exposure tests with galvanized and hot-dip zinc 5% Al steels in a rural environment at Kiryu-City, Gunma, and a coastal environment at Nakagusukuson+, Okinawa.

The exposure test lasted for a span of 8 years. In the rural setting, results revealed that the corrosion loss of ZAM coated steel is only at approximately 16-24 g/m2, while zinc with 5% Al coated steel is at ~38-51 g/m2, and the galvanized steel is at ~76-89 g/m2.

In the coastal environment, the corrosion loss result of ZAM® coated steels is ~33-43 g/m2, zinc with 5% Al coated steel is at ~66-82 g/m2, and the galvanized steel is at a high rate of ~105-115 g/m2.

In conclusion, ZAM coated steels are up to four times more corrosion-resistant than galvanized and hot-dip zinc 5% Al coated steels. 

Superior properties of ZAM coated steel

ZAM Coated Steel is an incredible brand product that lasts a lot longer even in the harshest environment settings, has built-in rust prevention on the cut edges and excellent press formability, and reduces the manufacturing cost by requiring less maintenance.

Highly resistant to steel corrosion

The non-oxidizing chemical properties of magnesium added to the traditional hot-dip zinc coating steel sheet make it up to 20 times more resistant to corrosion. Also, up to eight times more resistant compared to hot-dip zinc steel sheets coated with 5% aluminum alloy. 

Excellent Press Formability

The steel sheets of ZAM are built with a firmer and smoother coating surface compared to those made from hot-dip zinc coating. This is the reason why ZAM® coated steel sheets do not crack during forming conditions. After the shaping process, the flange area is also reduced.

Reduces manufacturing costs significantly

ZAM coated steel helps save manufacturing costs notably in a variety of ways. Again, because of its enhanced corrosion resistance, it allows life cycle cost reduction. It also allows for upfront cost savings through process omission.

Other exceptional properties:

• Product Longevity ー ZAM coated steel sheets are more sustainable than other steel products
• Light coating weight ー Plate thickness is only at 3.2 millimeters, but firmer
• Environment-friendly ー All product treatments adhere to environmental requirements, including RoHS directives to avoid the dangers of electrical waste disposal, and ELV systems to ensure that the system is controlled at a low voltage
• Saves coating and transportation costs ー ZAM contributes to cost reduction and shortens delivery time by eliminating the post-hot-dip galvanizing process

ZAM coated steels may be produced in a wide range of forms for different types of construction projects. It may be formed into a corrugated sheet, punching metal, non-slip metal, lightweight structural steel, pre-notched shaped steel, square pipes, and round pipes. 

ZAM can be used for road construction such as building railings and other civil engineering projects. It may also be utilized for farming projects such as establishing a greenhouse, compost house, or fish preserve. Lastly, ZAM® coated steels are also utilized in railroad and housing structures, the building of electric power equipment and automobile parts, and other applications.

Corrosion or rust may be avoided by creating a barrier on the surface of steel iron. This method is also known as surface treatment, wherein coatings are applied to iron in order to inhibit the chemical process of rust formation.

Corrosion protection mechanism on flat surfaces

SuperDyma is produced by adding Al, Mg, and Si to its original Zn coating and then relying on the composite effect of these added chemicals to achieve its great corrosion resistance. Once the coating layer is established, a protective film is generated on the surfaces. The corrosion resistance of flat surfaces will depend on the coating quality of this protective film. 

Corrosion protection mechanism on cut-end edges and welded parts

Red rust develops at the early step of treatment when the cut-end edges of the metal are exposed. However, the coating around the cut-ends is made up of zinc hydroxide, magnesium hydroxide, and basic zinc chloride, which leeches out to create a tight protective layer. 

The formed layer will completely cover the cut-end edge within a few months. Further, the silicon added to this coating helps to speed up the production of the protective film. 

To better understand the corrosion resistance mechanism, here is an overview of why corrosion happens in the first place:

What causes steel to rust?

Steel is created by combining carbon and iron at extremely high temperatures (above 2600°F). Pig iron is a melted down iron from ore that consists of greater carbon required for steel production. Pig iron is used in primary steelmaking.

Rust formation mechanism:

1. Moisture is absorbed into the surface of iron when it is exposed to water or rain. 
2. Oxygen from the air is subsumed into the moisture.
3. Moist removes the required electrons from the iron and generates OH– anions.
4. Iron (Fe) is converted to Fe3+ cations once the required electrons are released. 
5. OH- and Fe3+ combine to form Fe(OH3). Once moisture runs out (H2O), rust (Fe2O3) formation takes place.

Moisture and oxygen will permeate the base metal if the formed protective coating is too weak, allowing corrosion to begin. However, if a tight protective coating is produced, corrosion can be prevented. This is why SuperDyma possesses remarkable corrosion resistance due to its firm protective coating.

Comparison with conventional hot-dip zinc-coated sheet

The common hot-dip zinc-coated steel sheets also form a protective layer; however, it is rough in structure. This is why moisture and oxygen can still penetrate through the layer, leading to corrosion development. On the other hand, SuperDyma’s steel sheets are coated with a thick protective film on the surface allowing a more stabilized corrosion behavior.

Comparison with stainless steel, aluminum, and galvalume steel sheet

The passivated coating that develops on stainless steel’s surface provides good corrosion resistance; however, it has the drawback of being susceptible to salt corrosion. Meanwhile, the protective coating of SuperDyma’s surface protects it against salt damage. SuperDyma is significantly superior in situations where “red rust resistance” is critical.

Aluminum also offers a corrosion-resistant quality from the formed protective film on its surface. Galvalume steel sheet with a layer of 55% aluminum also displays equal efficacy. The downside is that alkali resistance is a problem for aluminum.

Galvalume steel sheets erode fast in an alkaline environment with a high pH, while SuperDyma is less susceptible to corrosion, remains almost intact, and maintains its excellent quality in alkaline settings. 

Ordinary metallic-coated steel sheets exhibit fast corrosion over a duration of 100 hours when immersed in an alkaline solution with a strong pH level of 12.5. On the other hand, SuperDyma remains stable and maintains minimal corrosion after 300 hours.

Excellent quality characteristics

SuperDyma possesses superb qualities ensuring that the steel products are of high quality even with reduced cost.

Highly rust resistant

SuperDyma’s corrosion resistance is excellent not only on flat surfaces but also on cut-edge surfaces. Alkali resistance is also exceptional. The addition of Al, Mg, and Si to the traditional zinc coating improves SuperDyma’s corrosion resistance. Silicon, when mixed with magnesium, has a strong anti-corrosion effect.

Exceptional weldability and paintability

SuperDyma has excellent coating adhesion and can endure rigorous fabrication procedures. The coating is firm, so it also provides outstanding scratch resistance. Thus, high-quality finishing with fewer scratches is achieved after steel fabrication.

Cost and time-efficient

In terms of value analysis, SuperDyma is remarkable. Manufacturing cost is highly reduced because the after-coating and post-painting process are not required. Faster delivery time is also anticipated. In addition, SuperDyma can be used to replace stainless and aluminum steel products.

In the production process of galvanized steel strip, it has gone through very rigorous procedures and multiple production processes. Now I will introduce the production process of galvanized steel strip.

The first step is to use the pickling process to clean and decontaminate the surface of the strip. Because the dirt and rust that usually exist on the surface of the strip may not be cleaned up, it may affect the galvanizing work on the surface. Generally, the whole coil of strip steel is uncoiled after pickling, and then cleaned to make the surface clean and tidy.

The second step is to mill the strip to the desired thickness and smooth the surface. After the rolling is completed, the next step is to galvanize it. The galvanizing work is actually very simple, just put it in a hot dip aqueduct, control the time and temperature, and you can get a smooth and uniform coating. Finally, put it into storage and you are done. The thickness of the galvanized layer is not fixed, and can be processed according to the different needs of customers.

Uses of Galvanized Steel Strip

Galvanized steel strip as a new material. The principle is that the surface of the steel plate is plated with a layer of zinc, which uses the physical properties of zinc to play a role in anti-corrosion. As a new material, galvanized steel strip is the most widely used in construction and light industry, accounting for about two-fifths of the total application.

In addition, galvanized strip steel is widely used in daily life as a kind of anti-corrosion treated steel. Just because of different uses and different processing forms, we may not have noticed, such as the ventilation ducts of buildings, and some electrical surfaces, after beautification treatment, are usually used in places we cannot see, such as the back cover of refrigerators, etc. Wait.

Can galvanized steel strip be stored outdoors?

Galvanized steel strip is the technology of coating the steel strip with a layer of zinc through high temperature and chemical process. Compared with ordinary steel, galvanized strip steel has many advantages, such as strong corrosion resistance, long service life, more rust resistance and so on.

Galvanized steel strip cannot withstand the sun for a long time. It needs a dry environment, but remember not to be exposed to sunlight for a long time. Long-term exposure will cause the zinc on the surface of the galvanized strip to fall off, thereby reducing the life. If it is placed outdoors for a long time, it will not only be exposed to the sun, but also may be attacked by heavy rain and lightning. For galvanized strip steel, long-term wind and rain will corrode it, which is not good for it.

Quality Control of Galvanized Steel Strip

If galvanized steel strip is often used in an acidic environment, it needs to be processed with an acid solution when the product is processed. And some processing machinery parts are made of strip steel, which can prevent parts from being corroded. After the product is produced, in order to judge whether the quality of the product meets the standard, it is necessary to carry out a series of inspection work on the product:

1. When testing, we must first check the appearance of the product, check whether the surface color of the product is bright, and then check the appearance size of the product to see if it meets the requirements.

2. The thickness of the coating film on the surface of the product can be measured with accurate measuring equipment. When measuring, the distance between the measuring part and the equipment should be less than 3 mm, and the interval between the products should be about the same. point and calculate their average.

3. After the production is completed, the product must be tested for the quantity of the product, and the experimental items and experimental methods used must comply with the regulations. Products made from galvanized strip are used in many processing industries and their role is irreplaceable. The quality of the galvanizing process directly affects the use of the product. Galvanized strip is processed from high-quality steel. Galvanizing density or galvanizing uniformity directly affects its performance.

How to Choose Galvanized Steel Strip

The first question is to see the thickness, width and length of the strip to be purchased, and then whether the galvanized strip to be purchased has flowers, and the requirements for the zinc layer. Finally, for its oiling situation, oiling is divided into light oiling and heavy oiling. There may also be environmental requirements for galvanized strip.

For galvanized strip, the quality of its quality mainly depends on the material and heat treatment of the strip, as well as the amount of zinc applied to hot-dip galvanizing. , 120 grams, at present, the weight of zinc in many factories is only about 40 grams, and the weight of zinc directly affects the anti-corrosion ability.

For the galvanized strip steel with poor quality, there are cracks on the surface, which are mostly caused by cracks and poor annealing, and the material is too hard.

The coating structure includes two coats and one bake, two coats and two bakes, etc. The maintenance-free service life can be 10-30 years depending on the ambient atmosphere.

The main production process of the common two-coating and two-baking type continuous color coating unit is uncoiler – stitching machine – pressing roller – tensioning machine – Uncoiling Looper – Alkaline Degreasing – Cleaning – Drying – Passivation – Drying – Beginning Coating – initial coating and drying – topcoat fine coating – topcoat drying – air cooling and cooling – winding work Set – rewinder – (the next roll is packed and put into storage).

The coating structure of the double-sided two-coated and two-baked color-coated steel plate is shown in the above picture

The upper surface is coated with two layers of paint, and the lower surface is coated with a layer of color-coated steel plate, as shown in the picture above (this kind of back paint is generally not suitable for front use)

Pre-Painted Steel Sheet is a product made of cold-rolled steel sheet, electro-galvanized steel sheet, hot-dip galvanized steel sheet, or galvanized steel sheet after surface degreasing, phosphating, and chromate treatment, and then coated with organic paint and baked. . The commonly used coatings for color-coated steel plates are polyester (PE), followed by silicon-modified polyester (SMP), PVDF, etc. The coating structure is divided into two coatings and one baking and two coatings and two baking. The thickness of the coating is generally 20- 25μ, backside is 8-10μ.

Construction

Color-coated steel coils are mainly used in construction projects. After being processed into corrugated boards or sandwich panels, they are mainly used in industrial buildings such as industrial plants and warehouses. Civil buildings are mainly used in roofs, gutters, and siding.

Home appliances

Generally, electro-galvanized and cold plates are used as the substrate and are commonly used in refrigerator casings or large air conditioner casings, freezers, refrigerators, washing machine casings, etc.