Iron gray 501 Baosteel Color Coated Steel Coil, SMP S-HDP livestock farming special AZ150 Baosteel Color Steel Sheet

　　Iron gray 501 Baosteel Color Coated Steel Coil, SMP s-hdp for Animal Husbandry AZ150 Baosteel Color Steel Sheet

　　Common grades of Baosteel's color coated steel plates and their mechanical properties

　　TDC51D+Z (TDC51D+AZ): Suitable for general construction use, with yield strength ranging from 230 to 3300, meeting daily needs for roofs, walls, hoarding, etc. in regular construction sheds.

　　TS280GD+Z (TS280GD+AZ): Yield strength greater than 280MPa, commonly used in roof structures, and meets the requirements for the use of medium and small span arch roofs.

　　TS350GD+Z (TS350GD+Z): Yield strength over 350 MPa, suitable for windy, snowy, ice-snowy climate conditions, large-span arch roof structures; not suitable for stamping.

　　TS550GD+Z (TS550GD+AZ): High-strength structural steel with yield strength exceeding 550 MPa, not suitable for stamping.

　　TDD51D+Z: No specified yield strength; tensile strength ranges between 270-500 MPa, elongation at break exceeds 22%.

　　TDC53D+Z: Yield strength 140-260 MPa, tensile strength 270-380 MPa; suitable for stamping, but not for structural panels used in steel structures like roofs and walls.

　　Baosteel's common coil coated steel grades and their mechanical properties

　　TDC51D+Z (TDC51D+AZ): General-purpose for construction, yielding strength between 230-3300, meeting daily requirements for roof, wall, fence, etc. in ordinary factory buildings.

　　TS280GD+Z (TS280GD+AZ): Yield strength over 280MPa, commonly used in roof structures, meeting the requirements for medium and small span arched roofs.

　　TS350GD+Z (TS350GD+Z): Yield strength exceeding 350 MPa, suitable for climates with strong winds, heavy snowfall, ice and snow, and large-span arch-shaped roofs; not suitable for stamping.

　　TS550GD+Z (TS550GD+AZ): High-strength structural steel with yield strength exceeding 550 MPa; not suitable for stamping use.

　　TDD51D+Z: No specified yield strength; tensile strength ranges between 270-500 MPa, elongation at break exceeds 22%.

　　TDC53D+Z: Yield strength 140-260 MPa, tensile strength 270-380 MPa; suitable for stamping, but not for structural panels used in steel frame roofs and walls.

　　Steel grade

　　In China, when it comes to choosing color-coated steel plates, consumers are less concerned about the steel grades. This is because most domestic color-coated steel plate manufacturers have a limited variety of steel grades, with the majority being DC51 (since the hot-rolled sheets or cold-rolled coils they purchase are essentially of one steel grade). Some manufacturers with galvanized steel lines produce full-hard steel (S550) or high-strength steel (S350, etc.) through heat-treated galvanizing, but this is very challenging as they have no control over the quality and chemical composition of the base material. Consequently, there is poor quality consistency, leading to significant performance fluctuations and deterioration in the quality of the press-formed steel plates.

　　For buildings, the load-bearing capacity (wind load, snow load, construction personnel and machinery), span, and rafter spacing design all depend on the strength of steel plates. For color-coated and galvanized aluminum-zinc steel plates used in building maintenance structures, there are corresponding standards internationally, such as ASTM653 and ASTM792 in the U.S., JISG3302 and JISG3321 in Japan, and EN10215 and EN10147 in Europe. These are categorized by steel type into CQ (Commercial Quality), DQ (General Drawing Quality), HSS (High-Strength Structural Steel), and FH (Full Hard Steel).

　　CQ Standard Commercial Grade

　　Non-ferrous metal smelting plants (such as copper, zinc, aluminum, lead, etc.) pose challenges to the lifespan of colored coated steel plates. However, reasonable material selection, design, and environmental protection investments can ensure or extend the lifespan of colored coated steel plates. Replacing or maintaining them every 10 years should be achievable.

　　DQ is generally used for stamping.

　　Due to the fact that most architectural color steel panels are roll-formed or composite core materials, which do not require high stamping properties, they are rarely used in the construction field (except for some window and door panels).

　　HSS High-Strength Structural Steel

　　HSS steels, compliant with the European standard, can be categorized into 4-5 different grades of strength. However, as standard CQ materials can replace low-strength HSS steels, the most commonly used in the market are grades with yield strengths of 280Mpa and 345Mpa. Baosteel's TSTE28 and TS350GD are examples of these grades. Compared to standard CQ, HSS steel offers several advantages: 1. It has good fire resistance and seismic resistance due to its lower yield strength ratio. 2. It can be used to manufacture large-span arch-shaped plates for thicker steel sheets. 3. For general exterior wall and roof panel designs, it can be made thinner than CQ materials, thereby saving material consumption.

　　FH Full Hard Steel

　　A steel grade that enhances the yield strength of steel plates by controlling the annealing temperature. According to international standards, the yield strength should be ≥550Mpa and the tensile strength ≥570Mpa. This material boasts high strength and low elongation, making it suitable for shallow-profiled forming steel plates, significantly reducing material usage. As a result, countries are competing to research and develop this type of steel. International standards also describe materials with high strength and good elongation. For instance, HSLA (Low Alloy High Strength) steel is produced by adding reinforcing alloy elements during steelmaking. However, due to its high strength, the rolling mill's reduction rate is limited, which is why thinner pre-painted steel sheets used for structural maintenance are rarely made from HSLA steel (another drawback is its high cost).

　　Based on Baosteel's many years of experience in steel grade usage, the guarantee of the finished product's plate shape for color-coated steel plates is closely related to the steel plate's strength grade, the shape of the press-formed steel plate, and the processing equipment.

　　In summary, the more processing steps, the better the panel shape, but slower processing speeds yield better shapes. For corrugated steel panels, shallow wave shapes are superior to high wave shapes. The trend of deteriorating panel shape after strength processing is more pronounced. Another reason for the relatively poor shape of high-strength steel is that many color-coated steel production plants rely solely on lowering the annealing temperature of hot-dip galvanized steel to increase the material's yield strength, which can lead to uneven mechanical properties along the width of the steel plate. This imbalance is caused by the uneven temperature distribution along the entire width of the strip steel, with temperature drops potentially causing some areas to be below the recrystallization annealing temperature of the steel plate.

　　Impact across various regions

　　The selection of color coated steel sheets in different regions primarily considers the local wind and snow loads, as well as corrosion conditions.

　　The wind and snow load primarily concerns the safety factor of the structure. Although it is related to the mechanical properties of the coated steel sheet, it is more concerned with the profile, thickness of the pressed steel sheets, and the connection between them (recommendations for steel material are described in the trend development). Quantitatively describing the corrosion environment of an area is relatively difficult. There are many factors that affect the corrosion of the coated steel sheet.

　　Impact on Different Industries

　　The usage of color-coated steel sheets across various industries can be analyzed from two aspects. Firstly, the outer sheet of color-coated steel sheets, typically, can be selected based on different regions, but the influence of the local environment should also be considered. This includes assessing whether corrosive agents like gases from boiler emissions or dust are deposited on the factory's protective structures. The design should account for factors like the height of the chimney and the predominant wind direction in the area. Additionally, the密封ness of the factory building should be considered; there is a possibility that high-temperature, high-humidity, and corrosive gases may escape from inside the factory, condense on the color-coated steel sheets when they meet cold air outdoors, leading to accelerated localized corrosion—a phenomenon to be avoided. The second aspect involves considering the inner sheet of color-coated steel sheets (double-layer composite steel) or the back paint (single-layer sheet). It's important to note that the inner sheet for roofing is generally more prone to corrosion than the one for walls. If workers can operate in such an environment, the use of color-coated steel sheets is acceptable. However, the quality of the indoor environment or the investment in environmental protection equipment will directly impact the lifespan of the color-coated steel sheets. A few years ago, Baosteel had two end-users in Guangxi, both producing electrolytic aluminum. Their experiences with the lifespan of the color-coated steel sheets varied significantly—one factory had their sheets completely worn through after one year of operation, while the other has been using theirs for over six years.

　　Non-ferrous metal smelting plant

　　Non-ferrous metal smelting plants (copper, zinc, aluminum, lead, etc.) are challenging the lifespan of color coated steel plates. However, the rational selection of materials, design, and environmental protection investments can ensure or extend the lifespan of color coated steel plates. Replacing or maintaining them every 10 years should be achievable.

　　Steel mills, power plants

　　Steel mills and power plants also produce corrosive mediums, but colored coated steel sheets have extensive experience in long-term use.

　　Machinery manufacturing

　　Polyurethane

　　A new type of topcoat developed in recent years boasts excellent comprehensive performance, is quite expensive, and is currently being promoted.

　　Acrylic Acid Resin

　　High performance, expensive, used only in specific fields (such as for containers).

　　Table of Performance Comparison for Different Coatings

　　Resin Type Hardness Bend Resistance Corrosion Resistance Weather Resistance Cost Film Thickness Requirement/um

　　Polyester - Excellent, Good, Good, Good, Excellent - 20

　　Acid Resin - Excellent, Good, Fair, Fair, Poor - 20

　　Silicone-modified Polyester - Good, Fair, Good, Excellent, Good - 20

　　PVC Adhesive - Excellent, Good, Fair, Poor 200

　　PVDF resin - Excellent quality, moderate price, competitive, with minor defects.

　　High-Durability Polyester - Good, Excellent, Good, Excellent, Good, 20

　　When selecting primer, two key factors are crucial: first, the adhesion between the primer, topcoat, and substrate, and second, the primer's contribution to the majority of the coating's corrosion resistance. From this perspective, epoxy resin is a viable option. If flexibility and UV resistance are considered, polyurethane primer can also be chosen.

　　For the backside coating, the correct choice is a two-layer structure if the color-coated steel plate is used as a single sheet, consisting of one layer of backside primer and one layer of backside finish paint. The primer should be the same type as the front, and the finish paint should be a single layer of light color (such as white) polyester. If the color-coated steel plate is used as a composite or sandwich panel, simply apply a layer of epoxy resin that excels in adhesion and corrosion resistance to the backside.

　　Currently, there are still many functional color coated steel plates, such as antibacterial, antistatic, thermal insulation, and self-cleaning types. The development of these products aims to meet specific customer needs, but sometimes it cannot兼顾 other performance aspects of the color coated products. Therefore, when selecting functional color coated steel plates, users must clearly define their true requirements.

　　Coating

　　Many factors should be considered when selecting a coating, including the type of coating, coating thickness, coating color, and sheen. Additionally, requirements for the base paint and backside coating may also need to be considered.

　　Coating

　　Currently, hot-dip galvanized and aluminum-zinc coatings are widely used for architectural colored steel sheets. The thicker the coating, the better its corrosion resistance.

　　Coating thickness primarily affects the cut corrosion performance of color coated steel plates, where cut corrosion is electrochemical in nature. Influencing factors include the pretreatment layer, primer, substrate thickness, and coating thickness. Under normal circumstances, the pretreatment layer and primer are relatively fixed, so the substrate thickness and coating thickness are the main factors affecting cut corrosion performance. Thinner substrates and thicker coatings result in better cut corrosion resistance. Regarding this, there are many studies internationally, and the currently widely accepted standard is the zinc ratio. This is defined as the grams per square meter of coating weight per millimeter of substrate thickness. It is believed that a zinc ratio greater than 100 is a guarantee for effectively preventing cut corrosion of color coated steel plates. For instance, a 0.6mm steel plate would require a coating weight of 60 grams per square meter. Although aluminum-zinc coated sheets have better corrosion resistance than hot-dipped galvanized sheets, the zinc ratio also applies to hot-dip aluminum-zinc coatings in terms of cut corrosion spread.

　　When choosing between hot-dip galvanized and hot-dip aluminum-zinc coatings, it primarily depends on the acidity or alkalinity of the environment in use. Both zinc and aluminum are amphoteric metals, but they exhibit different behaviors in acids and bases. Pure zinc performs better in alkaline mediums than aluminum-zinc alloys. Conversely, in acidic cleaning mediums, the performance is the opposite. Therefore, it is recommended to use aluminum-zinc coated steel in relatively acidic environments, and hot-dip pure zinc coated steel in relatively alkaline environments. Based on experience, materials like wet wood and concrete should not be in prolonged contact with aluminum-zinc coated substrates.

　　Steel grade

　　In China, when it comes to choosing colored steel coil, consumers are less concerned about the type of steel. Most domestic colored steel coil manufacturers have a limited variety of steel types, with DC51 being the most common (since the hot-rolled sheets or cold-rolled coils they purchase are generally of one steel type). Some manufacturers with galvanized steel lines produce full-hard steel (S550) or high-strength steel (S350, etc.) through heat-dip galvanizing and annealing, but this process is very challenging, as they have no control over the quality and chemical composition of the base material. Consequently, the quality stability is poor, leading to significant performance fluctuations and degradation in the quality of the pressed steel sheets.

　　For buildings, the load-bearing capacity (wind load, snow load, construction personnel, and machinery), the span of the building, and the design of the rafter spacing all depend on the strength of the steel plate. For color-coated and galvanized aluminum zinc steel plates used in building maintenance structures, there are corresponding standards internationally. Such as the ASTM653 and ASTM792 in the United States, the JISG3302 and JISG3321 in Japan, and the EN10215 and EN10147 in Europe. Steel grades are categorized into CQ (Commercial Quality), DQ (General Drawing Quality), HSS (High-Strength Structural Steel), and FH (Full Hard).

　　CQ Standard Commercial Grade

　　Non-ferrous metal smelting plants (copper, zinc, aluminum, lead, etc.) challenge the lifespan of color coated steel plates. However, reasonable material selection, design, and environmental protection investments can ensure or extend the service life of color coated steel plates. A replacement or maintenance every 10 years should be achievable.

　　DQ for general stamping use

　　Due to the fact that most architectural color steel panels are roll-formed or composite core materials, they have low requirements for material stamping properties, hence they are rarely used in the construction field (with the exception of some door and window panels).

　　HSS High-Strength Structural Steel

　　HSS steels, compliant with European standards, can be categorized into 4-5 different strength grades. However, due to the ability of ordinary CQ-grade materials to replace low-strength HSS steels, the most commonly used in the market are grades with yield strengths of 280Mpa and 345Mpa. Baosteel's TSTE28 and TS350GD are examples of these two grades. Compared to ordinary CQ, HSS steel offers several advantages: 1. It has good refractory and seismic properties due to its lower yield-to-tensile strength ratio. 2. It can be used to produce large-span arch-shaped plates for thicker steel sheets. 3. For general exterior wall and roof panel profiles, it can be appropriately thinner than CQ materials, thereby saving material consumption.

　　FH Full Hard Steel

　　This type of steel is enhanced by controlling the annealing temperature to increase the yield strength of steel plates. According to international standards, the yield strength should be ≥550Mpa and the tensile strength ≥570Mpa. This material boasts high strength with low elongation, making it suitable for shallow-profiled forming steel plates, significantly reducing material usage. As a result, countries are competing to research and develop this steel type. International standards also describe materials that require high strength and good elongation. For instance, HSLA (high-strength low-alloy) steel is produced by adding reinforcing alloy elements during steelmaking. However, due to its high strength, there are limitations on the reduction rate during rolling in steel mills, which is why thinner pre-painted steel sheets used for structural maintenance are rarely made from HSLA steel (another drawback is its high cost).

　　Based on Baosteel's years of experience in steel grades usage, the guarantee of the finished product's sheet shape of color-coated steel plates is closely related to the steel plate's strength grade, the sheet shape of the formed steel plate, and the processing machinery.

　　In summary, the more processing steps, the better the panel shape, but slower processing speeds lead to better shapes. For corrugated steel sheets, the panel shape of shallow-waved sheets is superior to that of high-waved sheets. The trend of worsened panel shape after strength processing is more pronounced for steel strength. Another reason for the relatively poor panel shape in high-strength steel is that many color-coated steel production plants rely solely on lowering the annealing temperature of hot-dip galvanized steel to increase the material's yield strength, which can result in uneven mechanical properties along the width of the steel sheet. This imbalance is caused by the non-uniform temperature across the entire width of the strip, with a drop in temperature potentially leading to some areas being below the recrystallization annealing temperature of the steel sheet.

　　Impact across various regions

　　The selection of color coated steel plates in different regions primarily considers the local wind and snow loads as well as corrosion environments.

　　The wind and snow load primarily considers the safety factor of the structure. Although it is related to the mechanical properties of the color coated steel plate, it is more related to the profile, thickness of the steel plate, and the connection between plates (recommendations for steel plate materials are described in the trend development). Quantitatively describing the corrosion environment of an area is relatively challenging. There are many factors that affect the corrosion of color coated steel plates.

　　Impact on Various Industries

　　The use of color coated steel plates across various industries can be analyzed from two aspects. Firstly, the exterior panels of color coated steel plates can generally be selected based on different regions, but the influence of the local environment must also be considered. This includes whether corrosive agents, such as gases or dust from boiler emissions, fall onto the factory's protective structures. Design considerations should include the height of the chimney and the primary wind direction in the area. Additionally, the sealing integrity of the factory should be assessed, as high temperature and humidity within the factory, accompanied by corrosive gases, may escape outdoors and condense on the color coated steel plates when encountering cold air, leading to accelerated local corrosion. The second aspect involves considering the interior panels (double-layer composite steel plates) or the backside paint (single-layer plates). It should be noted that the interior panels of the roof are relatively more prone to corrosion than those of the walls. If workers can operate in this environment, the use of color coated steel plates is acceptable. However, the quality of the indoor environment or the investment in environmental protection facilities will directly affect the lifespan of the color coated steel plates. A few years ago, Baosteel had two end-users in Guangxi, both producing electrolytic aluminum. However, the lifespan of their color coated steel plates varied significantly; one factory's plates were completely worn through after one year of operation, while the other has been in use for over six years.

　　Non-ferrous metal smelting plant

　　Non-ferrous metal smelting plants (copper, zinc, aluminum, lead, etc.) challenge the lifespan of color coated steel plates. However, reasonable material selection, design, and environmental protection investments can ensure or extend the service life of color coated steel plates. A replacement or maintenance every 10 years should be achievable.

　　Steel mills, power plants, etc.

　　Steel mills and power plants also produce corrosive media, but colored coated steel plates have long-term usage experience.

　　Machinery manufacturing

　　The mechanical manufacturing industry (including automotive, steam turbines, machine tools, etc.) generally does not negatively impact color-coated corrosion. However, attention should be given to industries with heat treatment furnaces, boilers, etc., which can affect local environments. Poor handling may lead to corrosion of color-coated steel plates, especially at processing damage or cutting edges.

　　Warehouse Logistics

　　This industry is developing rapidly, with a high usage of light steel. It does not corrode color coated steel plates inherently. The selection of color coated steel plates primarily considers the impact of the broader environment. Such projects are usually concentrated in industrially developed and busy traffic areas, which are industrial environments and coastal regions.

　　Commercial and民用 Buildings

　　Aesthetics and durability are the primary considerations for color coated steel sheets. Therefore, the coating's resistance to discoloration, chalking, and the smoothness of the coating surface are quite important. As public and residential buildings are often densely populated and situated in close proximity, the choice of paint typically favors PVDF or HDP, with light colors being more commonly selected.

　　Coated Steel Sheet Processing

　　Roll-forming

　　Roll forming is a common method for producing architectural roof and wall panels from color coated steel sheets. The roll forming machine shapes steel coils into the desired form through a frame equipped with a series of rollers of different shapes. The shapes of the color coated steel sheets vary depending on the strength and elongation of the steel, the characteristics of the paint, the model of the press, and its maintenance condition. To enhance the field performance of the color coated steel sheets, particularly in the area of steel plate deformation, the following usage guidelines should be adhered to:

　　Utilizing a large bend radius design. A large bend radius design allows for deep architectural shape requirements.

　　Rolling design ensures steel plate deformation from center to edge.

　　Rolling design coordinates with steel plate strength, for example: for high-strength steel plates, the same shape deformation may require more passes.

　　Complex shapes should be made from low-strength steel plates to allow for greater design margin.

　　Maintain roller press equipment to ensure proper level and vertical alignment, as well as sufficient gap between the rotating rolls for up and down movement, to prevent coating abrasion and damage to the surface paint during roller cleaning.

　　Utilize a flexible undercoat and topcoat system to enhance the performance of steel plates during bending.

　　Polyurethane

　　A new type of topcoat developed in recent years boasts excellent comprehensive performance, comes with a high price tag, and is currently being promoted.

　　Acrylic Acid Resin

　　High performance, expensive, used only in specific fields (such as for containers).