1.What are the differences in the production processes of different substrates?
Cold-rolled substrate: Made from hot-rolled steel sheets, cold-rolled (rolled at room temperature), annealed, and smoothed, with no surface coating.
Hot-dip galvanized substrate: Used as a base material, cold-rolled steel sheets are dip-coated in a high-temperature molten zinc bath (hot-dip galvanizing), resulting in a pure zinc coating (Zn layer).
Hot-dip galvanized substrate: Used as a base material, cold-rolled steel sheets are dip-coated in a high-temperature molten zinc bath to form a pure zinc coating (Zn layer).
2.What are the differences in core processes for different substrate types?
Cold-rolled substrate: Low cost, a basic substrate; smooth and flat surface, suitable for subsequent color coating; poor corrosion resistance (no coating protection), prone to rust.
Hot-dip galvanized substrate: Strong coating adhesion, customizable zinc thickness (commonly 30-275g/㎡); superior corrosion resistance to cold-rolled substrate, capable of withstanding mildly humid and dusty outdoor environments; and cost-effective, making it one of the most popular substrates.
Hot-dip aluminum-zinc substrate: The corrosion resistance is far superior to hot-dip galvanizing (3-5 times that of pure zinc layer) because aluminum can form a dense oxide film that isolates air and moisture; it has good high temperature resistance (can withstand short-term high temperatures of 300℃) and is not easily discolored by high temperatures; the coating has high hardness and is more scratch-resistant and impact-resistant.
3.What other special substrate types are there?
Cold-rolled galvanized iron alloy substrates: This treatment, called "iron alloying," is applied to hot-dip galvanizing, transforming the coating from pure zinc to a zinc-iron alloy (such as a Zn-Fe alloy). This provides enhanced adhesion and weldability, making it suitable for industrial equipment housings requiring welding.
Stainless steel substrates: Based on stainless steels such as 304 and 201, the surface is directly color-coated. While highly corrosion-resistant, this approach is costly and limited to applications requiring high corrosion and cleanliness requirements (such as walls in food processing plants and pharmaceutical workshops).
Aluminum substrates: Based on aluminum alloy sheet, they are lightweight (with a density only one-third that of steel) and corrosion-resistant, making them suitable for applications requiring minimal weight (such as portable prefabricated buildings and temporary exhibition stands). However, their strength is relatively low, requiring a supporting structure.
4.What are the core considerations for substrate selection?
Corrosiveness of the operating environment: Choose hot-dip galvanized substrates for coastal/humid areas, cold-rolled substrates for dry indoor environments, and hot-dip galvanized substrates for ordinary outdoor environments.
Cost budget: Cold-rolled substrates < hot-dip galvanized substrates < hot-dip galvanized substrates < stainless steel/aluminum substrates. A balance between performance and cost is required.
Post-processing requirements: Choose galvanized iron alloy substrates for welding, aluminum substrates for lightweighting, and hot-dip galvanized/hot-dip galvanized substrates for high strength.
5.Which type of color-coated corrugated board is more suitable for the construction industry?
In the construction industry, the choice of substrate for color-coated corrugated boards must focus on the three core requirements of weather resistance, durability, and cost adaptability of the building scene. Combined with the performance differences of different substrates, the mainstream choices are concentrated on hot-dip galvanized substrates and hot-dip aluminum-zinc substrates, which cover the vast majority of building application scenarios.