The material requirements for the building itself (roof panels and facade panels) can be categorised into safety properties (impact, wind and fire resistance), housing properties (water, thermal and acoustic insulation), durability (resistance to contamination, weathering and retention of appearance), and type of production and processing (economy, ease of processing, ease of maintenance and repair) Safety and longevity are critical for the building's ultimate owner. For design firms, longevity, load-bearing capacity, and appearance are even more important. For the forming process of the walls and roofs of a building, the workability of the colour coated panels (surface hardness, abrasion resistance, shape of the panels and strength of the steel sheets) is preferred.
Of course, the quality of colour-coated mainly depends on the colour-coated steel as it leaves the factory, but the appearance and service life of the final product can also be damaged to varying degrees if the equipment and methods of processing and installation are not appropriate.
Performance indicators of colour coated steel include.
Substrate:Yield strength, tensile strength, elongation Cladding:Coating weight and bonding strength Coating:Colour difference, gloss, T-bend, impact, hardness, powder resistance, moisture resistance and heat resistance. Surface:Surface defects visible to the naked eye. Sheet type:Tolerance, roughness, etc.
High Speed Steel
High Strength Structural Steel:According to the European standard HSS, it can be classified into 4-5 types of steel with different strengths. However, more steel grades with yield strengths of 290 MPa and 345 MPa are used in the market as common CQ grade material has been able to replace low strength HSS. The TS280GD and TS350GD produced by Baosteel are these two types of steel.
Compared with ordinary CQ, HSS has several advantages.
1) Due to its low flexural properties, the steel has good fire resistance and seismic resistance.2) It can be used to fabricate large-span arched panels as compared to thicker steel plates.3) For general exterior wall and roof panels, it can be thinner than CQ material to save material consumption.
Next is the selection of coatings, coatings are considered to ensure the durability and corrosion resistance of the building, different uses can choose different coatings, coatings and thicknesses to meet its service life
1. Plating layer
Commonly used coatings in buildings are hot dip galvanising and hot dip aluminium zinc. For coloured coatings, the areas of application of the two substrates are not very different. In relatively acidic environments, aluminium-zinc substrates are the better choice. For use in humid and alkaline environments, the corrosion resistance of the galvanised substrate cut can be demonstrated. For coating thicknesses, the general requirements on roofing panels and cladding are 180 g/m2 or approx. 26 (um) for hot dip galvanising and 100 g/m2 or approx. 27 um for aluminium zinc plating . When used in heavy industry or in beach environments, there will be a minimum amount of galvanising as the Australian Standard ECCA specification requires a galvanising content of 275 g/m2 or zinc coating (approx. 38 um) and 150 g/m2 for aluminium zinc plating (approx. 40 um).
2. Coating
To meet the user's colour needs and durability requirements. For the processor, it must meet its processing performance. It is therefore necessary to specify the type of coating, the colour and gloss as well as the thickness of the coating when ordering.
Nowadays, the commonly used varieties of top coatings for steel coil coating are polyester (PE), polyurethane (PU), silicone-modified polyester (SMP), fluorocarbon (PVDF), and high-weathering polyester (HDP), and the varieties of primer and backing varieties are epoxy (EP), polyester (PE), and polyurethane (PU).