In the field of modern construction and industrial manufacturing, color steel plate (also known as color coated steel plate) has become an indispensable building material because of its lightweight, beautiful, corrosion-resistant and construction convenience advantages. For the user, one of the most concerned questions is: color steel plate can be used how long? In this paper, we will analyze the service life of color steel plate from the material composition, using environment, coating type, maintenance way and other dimensions, and explain with different application fields.

1.Definition of color steel plate

Color steel plate is a composite material formed by taking metal steel plate as the base material, covering one or more layers of metal plating and organic coating on its surface, through roller coating, baking and other processes. It integrates the mechanical strength and plasticity of steel, the anti-corrosion property of metal plating layer and the decorative property of coating. 

Main components.

-Substrate:Commonly used cold rolled steel plate, with high strength, but easy to rust, so it must be protected by plating.

-Plating: Commonly hot-dip galvanized or aluminum zinc plating layer, to play the role of anti-corrosion barrier.

-Primer layer: Enhances the adhesion between the coating and the substrate to prevent peeling.

-Topcoat layer:Determine the color, decorative effect and weather resistance of the color steel plate.

Common coating types include.

-PE (polyester coating): cost-effective, suitable for buildings with general requirements for life, outdoor service life of about 5-10 years;

-SMP (Silicon Modified Polyester Coating): better weathering than PE, UV and chalking resistant, life expectancy up to 10-15 years;

-PVDF (Fluorocarbon coating): with excellent UV and chemical resistance, it is widely used in high-end architectural curtain walls and coastal areas, with a life expectancy of more than 20-30 years.

Reference data:GB/T 12754-2019 Coated Steel Sheet for Construction, ASTM A755/A755M all make provisions for the types of color steel plate and life assessment.

 

2. The characteristics of color steel plate

(1) beautiful and practical.

Color steel plate adopts anti-corrosion and weather resistance of polymer film, colorful, full, not only to meet the requirements of people for the building aesthetics, but also has anti-corrosion, heat insulation, heat preservation, flame retardant and other multiple practical performance.

(2) Strong anti-corrosion.

The surface of color steel plate adopts galvanized, baking paint and other processing technology, has good anti-corrosion performance. Even under the harsh environmental conditions, color steel plate can maintain the surface aesthetics and use function.

(3) High safety.

Color steel plate is made of lightweight materials, light weight, easy to install, reducing the load on the building structure and improving the overall safety of the building.

(4) Good sound insulation performance.

Color steel plate is filled with polyurethane and other materials inside, which has good sound insulation and sound-absorbing performance, and can effectively inhibit heat loss and noise pollution and other problems.

 

3.Application scope of color steel plate

(1) Engineering construction

Color steel plate is widely used in engineering construction. It is used as wall, roof, heat insulation material, etc. It has the functions of waterproof, fireproof, sound insulation, etc. It is suitable for all kinds of buildings, such as factory buildings, warehouses, stations, airports, etc. It is also widely used in agriculture and fishery production.

(2) Agriculture and fishery

Color steel plate is also widely used in agriculture and fishery production. It can be used as greenhouses, covering materials of farms, cargo sheds and so on. Color steel plate has good waterproof performance, which can ensure the smooth progress of agriculture and fishery production.

(3) Transportation

As a building material, color steel plate is widely used in the field of transportation. It can be used to build garage, station waiting room, highway guardrail, etc. It has the advantages of fireproof, rainproof, corrosion-resistant and so on.

 

4.Service life range of color steel plate

The service life of color steel plate is not a fixed value, but an interval value. It depends on multiple factors such as material selection, use environment, maintenance level and so on. Overall:

-Ordinary environment (city, inland area): generally can be used for 10-15 years;

-Industrial area or seriously polluted area: the air contains corrosive gases, the life expectancy is shortened to 8-12 years;

-Coastal high salt spray area: if choose aluminum-plated zinc + PVDF coating, the life expectancy can be maintained for more than 20 years;

-Indoor use (ceiling, partition, furniture, etc.): the corrosivity is low, the life expectancy of color steel plate can be more than 30 years.

 

5. The main factors affecting the life of color steel plate

(1) Environmental conditions

Coastal environment: high salt in the air, corrosive;

Industrial environment: SO2 and other polluting gases will accelerate the oxidation of steel plate;

Dry areas: corrosivity is small, the life of the colour steel plate is significantly extended.

(2) Coating quality

Coating thickness: common 20-25μm, the thicker the coating, the better the durability;

Coating type: PVDF > SMP > PE.

(3) Substrate plating weight

Common galvanization amount is Z120~Z275g/m2;

The thicker the coating, the stronger the corrosion resistance.

(4) Processing and construction

Improper cutting during processing will damage the coating and lead to rust at the incision;

Poor sealing during construction and rainwater infiltration will also accelerate corrosion.

(5) Use and maintenance

Regular cleaning of dust, oil and corrosive deposits can prolong the life;

If the local coating is damaged, it should be repaired in time.

 

6. Life performance in different application scenarios

(1) Industrial plant roof and wall

-General use of PE or SMP coating, life expectancy of 10-15 years.

-If PVDF is used, it can reach more than 20 years.

(2) Public buildings

such as airports, gymnasiums, shopping malls curtain wall, commonly used PVDF color steel plate, life expectancy of 25 years or more, and easy to clean and maintain.

(3) Cold storage and clean workshop

using sandwich color steel plate (polyurethane/rock wool), the internal environment is stable, life expectancy 20-30 years.

(4) Transportation

Cargo carriages, high-speed rail car body commonly used wear-resistant color steel plate, life expectancy than ordinary steel plate extended 3-5 times.

(5) Home appliance manufacturing

refrigerator, washing machine shell using VCM laminated color steel plate, indoor environment can be used for more than 30 years.

 

7. How to extend the life of color steel plate

(1) Regular cleaning and inspection:

- Rinse the surface with water or neutral cleaner every half a year to avoid dust, bird droppings accumulation corrosion coating.

- Focus on checking the seams, screws whether water seepage, timely repair.

(2) Avoid mechanical damage:

- Use non-marking tools during installation to prevent scratching the coating.

- Reinforce the plate before the typhoon to reduce the risk of tearing by wind pressure.

(3) Coating maintenance and renovation:

- Spray special anti-corrosion top coat (e.g. acrylic urethane) every 5-8 years, cost 60% lower than replacement.

- Localized corrosion can be repaired by sandpaper sanding and applying antirust primer + top coat.

(4) Optimization of drainage system:

- Ensure that the slope of the roof is ≥5% to avoid accumulation of water leading to soaking and aging of the coating.

- Install eaves gutter to reduce edge corrosion.

(5) Environmental adaptability selection:

- High humidity areas are prioritized to use aluminum zinc-plated substrate + PVDF coating, salt spray resistance is increased by 3 times (ASTM B117 test).

(6) Professional installation and design:

- Adopt hidden screw fixing method to reduce perforation leakage.

- Reserve a gap for thermal expansion and contraction (10mm gap for every 6 meters is recommended).

8. Industry standards and life reference

China standard: “GB/T 2518-2021 continuous hot-dip galvanized steel sheet” requires Z275 coating can be maintained in hot and humid environment for more than 15 years;

Japan and the United States: more than the use of PVDF color steel, life expectancy of an average of more than 25 years;

Europe: part of the high-end curtain wall projects and even require the design of the color steel plate life of more than 30 years.

 

Color steel plate as a modern building and manufacturing industry indispensable important materials, its service life by the coating performance, substrate plating, environmental conditions, processing and construction and post maintenance and other multiple factors. Overall, high-quality color steel plate in reasonable use and scientific maintenance, life can fully meet or even exceed the demand of 20-30 years.

With the continuous development of new coating technology, intelligent manufacturing process and green environmental protection concept, the weather resistance and environmental protection performance of color steel plate will be further enhanced to provide more durable and reliable material guarantee for industrial plants, public buildings, transportation, home appliance manufacturing and many other fields. For users, choosing the right type of product, combined with scientific construction and maintenance, not only can prolong the use cycle of color steel plate, but also significantly reduce long-term operating costs.

In the future, color steel plate will continue to play a more important role in the global construction and industrial market by virtue of its advantages of light weight, high strength, beautiful appearance and durability and reliability, and become one of the key materials to promote industrial upgrading and sustainable development.