I. Definition and Overview

Colour Steel Plates

 

Colour steel plates are steel plates with an organic coating. This organic coating can be applied to the surface of the steel plates through processes such as roller coating and spraying. Its main purposes are to improve the corrosion resistance of the steel plates and endow them with a rich variety of colours. Coating materials usually include polyester, silicon-modified polyester, polyvinylidene fluoride (PVDF), etc. Polyester coatings have good weather resistance and decorative properties and are relatively affordable in price. PVDF coatings, on the other hand, possess more excellent weather resistance, corrosion resistance and self-cleaning properties and are often used in occasions with high requirements for durability.

Wave Plate

 

A wave plate refers to a colour steel plate with a wavy shape. This wavy shape is formed by processing flat colour steel plates through special forming equipment. The wavy shape not only increases the strength and stiffness of the colour steel plates, enabling them to better withstand external forces acting on walls and roofs, such as wind forces and snow loads, but also has good drainage performance. For wave plates used on roofs, their wavy shape helps rainwater or snow to slide off quickly, reducing the damage caused by water accumulation to the roof structure.

For Wall And Roof Use

 

Colour steel plates (wave plates) used for walls and roofs are commonly used materials in the construction field. In terms of walls, they can serve as the enclosure structure of exterior walls, playing the roles of decoration and heat preservation. For roofs, they can form a waterproof layer to protect the interior of buildings from natural factors such as rainwater and sunlight. Meanwhile, due to their rich colours, they can be selected according to the requirements of architectural design to enhance the aesthetics of buildings.

II. Chemical Composition and Performance Characteristics

Chemical Composition (Mainly of the Substrate)

 

The substrate of colour steel plates is usually cold-rolled steel plates or galvanized steel plates. The main chemical components of cold-rolled steel plates include carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), etc. The carbon content is generally between 0.05% and 0.15%. It is a key element that affects the strength of steel. The silicon content is approximately between 0.05% and 0.30% and can improve the strength and antioxidant properties of steel. The manganese content is between 0.20% and 0.50% and can enhance the toughness and cold working performance of steel. Phosphorus and sulfur are impurity elements. The phosphorus content generally does not exceed 0.04%. Excessive phosphorus will lead to cold brittleness. The sulfur content does not exceed 0.04%. High sulfur content will cause hot brittleness. Galvanized steel plates form a zinc layer on the surface of cold-rolled steel plates through hot-dip galvanizing or electro-galvanizing methods. The main component of the zinc layer is zinc (Zn), and the existence of the zinc layer greatly improves the corrosion resistance of the steel plates.

Performance Characteristics

 

Mechanical Properties

 

Yield Strength: For colour steel plates with ordinary cold-rolled substrates, the yield strength is generally between 180 MPa and 300 MPa. The yield strength determines the load at which the colour steel plates will undergo obvious plastic deformation, which is very important for the stability of wall and roof structures when they are subjected to external forces such as wind loads and self-weight.

Tensile Strength: The tensile strength is usually between 270 MPa and 420 MPa, reflecting the ability of the colour steel plates to resist tensile fracture. When the roof is subjected to strong wind uplift forces or the wall is subjected to lateral thrust forces, sufficient tensile strength can prevent the colour steel plates from being torn.

Increased Stiffness and Strength (Wavy Shape): Compared with the flat plate structure, the flexural stiffness and strength of wavy colour steel plates are significantly improved. This enhanced performance enables them to withstand larger vertical and horizontal loads, such as the snow load on the roof and the wind load on the wall.

 

Surface Properties

 

Corrosion Resistance: The organic coating of colour steel plates is the key to their corrosion resistance. Different coating materials have different corrosion resistance properties. Polyester coatings can provide relatively good protection in general environments, while PVDF coatings can still maintain good corrosion resistance under harsh climatic conditions (such as acid rain and high salt fog environments near the sea). Meanwhile, the zinc layer of the galvanized substrate itself also plays a sacrificial anode protection role for the internal steel plate, that is, when the zinc layer is corroded, zinc will be consumed preferentially to protect the main body of the steel plate.

Colour Performance and Decorativeness: Rich colours are a major feature of colour steel plates. A variety of colour options can be provided according to architectural styles and customer needs. Moreover, the glossiness, colour stability and other properties of the coating are also important. High-quality coatings have relatively small colour changes after long-term exposure to sunlight and rain, and can maintain the consistency of the appearance of buildings.

 

Heat Preservation and Insulation Properties
Colour steel plates used for walls and roofs can improve their heat preservation and insulation performance by adding thermal insulation materials inside. Common thermal insulation materials include expanded polystyrene foam (EPS), polyurethane foam (PU), etc. These thermal insulation materials filled in the interlayer of the colour steel plates can effectively reduce the heat transfer between the inside and outside of buildings and reduce energy consumption.

 

Waterproof Performance (Mainly for Roofs)
Wave plates used for roofs have good waterproof performance due to their shape and surface coating. Rainwater can slide off quickly on the wavy surface, and the coating can prevent rainwater from penetrating into the interior of the steel plates, thus protecting the interior of buildings from rainwater damage.

III. Application Fields and Manufacturing Processes

Application Fields

 

Industrial Buildings: They are widely used in industrial buildings such as factories and warehouses. As wall and roof materials, they can quickly build building structures, and their corrosion resistance and wear resistance can meet the requirements of industrial environments. For example, in the construction of steel mill workshops, colour steel plates (wave plates) can withstand the high temperature, dust and a certain degree of chemical corrosion in the workshop.

Civil Buildings: They are used for non-load-bearing exterior walls and roofs of residential buildings, commercial buildings, etc. In some light steel structure residences, colour steel plate (wave plate) walls can serve as exterior facade decorative materials while playing a heat preservation role. In scenarios such as roof gardens of commercial buildings, they can serve as waterproof layers and decorative layers.

Temporary Buildings: Such as temporary office areas on construction sites and prefabricated houses. The easy installation and recyclable characteristics of colour steel plates (wave plates) make them ideal materials for temporary buildings. They can quickly build temporary residences or workplaces, and can be disassembled and used in other places after the project is completed.

Manufacturing Processes

 

Substrate Preparation
If it is a cold-rolled substrate, first, the steelmaking and hot rolling processes are carried out. The steel billet is heated and rolled to obtain hot-rolled steel plates, and then pickled to remove the oxide scale, and then cold-rolled by a cold rolling mill to the required thickness. If it is a galvanized substrate, on the basis of cold-rolled steel plates, a zinc layer is formed on the surface through hot-dip galvanizing or electro-galvanizing processes. In hot-dip galvanizing, the steel plate is immersed in molten zinc to make the zinc layer adhere evenly. In electro-galvanizing, zinc is deposited on the surface of the steel plate through an electrolytic method.

 

 

 

 

 

Grade	(wt%)Chemical Composition(wt%)
	C	Si	Mi	P	S	Cr	Ni	Mo	Cu	As	Sb
12Cr2Mo1R(H)	≤0.15	≤0.15	0.30-0.60	≤0.010	≤0.010	2.0-2.5	≤0.20	0.90-1.10	≤0.20	≤0.016	≤0.003

 

 

 

Coating Process
The main coating processes include roller coating and spraying. Roller coating evenly applies the coating to the surface of the steel plate through rollers. This method results in a uniform coating thickness and high production efficiency. Spraying uses a spray gun to spray the coating onto the surface of the steel plate, which is suitable for situations with special requirements for the appearance of the coating (such as imitating stone textures). After coating, the steel plate needs to be cured in a curing furnace to make the coating firmly adhere to the surface of the steel plate. The curing temperature and time depend on factors such as the type and thickness of the coating.

 

Forming Process (Wave Plate)
The flat steel plate coated with the coating is processed through forming equipment. There are a series of rolls in the forming equipment. By adjusting the shape and spacing of the rolls, the flat steel plate can be pressed into a wavy shape. During the forming process, parameters such as pressure and speed need to be controlled to ensure the shape accuracy and surface quality of the wave plate.

 

 

 

 

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We take pride in our ability to provide custom solutions for our customers' unique needs.
We analyze and compare the previous products and the current technical situation of our Colour Steel Plates (Wave Plate) For Wall And Roof Use, and develop new technical specifications and processes.
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