Galvanized Color Coated Coil: Corrosion-Resistant, Colorfast, Roofing/Wall/Decoration

Price Negotiable

Price: 400-700 USD/Ton

MOQ: 1 Ton

Delivery Time: 7 - 15 Days

Brand: ZHONGQIANG

Product Description

Service Life & Selection Guide of Color Coated Steel Sheets

I. Service Life of Color Coated Steel Sheets

The service life of color coated steel sheets mainly depends on three core factors: base plate material, coating process and service environment. The typical service life ranges are as follows:

Ordinary Civil Grade

The base plate is cold-rolled steel sheet with single/ thin coating, suitable for temporary buildings (e.g., construction site prefabricated houses).

Service life: 5–10 years. Coating fading and rusting are prone to occur.
Industrial Standard Grade

The base plate is hot-dip galvanized/galvalume steel sheet, with polyester (PE) or silicone-modified polyester (SMP) coating. It is applicable to workshops and warehouses.

Service life: 10–20 years. It has moderate weather resistance and is suitable for dry or slightly corrosive environments.
High-end Weather-resistant Grade

The base plate is galvalume steel sheet (zinc-aluminum content ≥55%) with polyvinylidene fluoride (PVDF) coating. It is designed for coastal areas, highly corrosive industrial zones or high-end building exterior walls.

Service life: 20–30 years. It boasts excellent UV resistance, acid-alkali resistance and salt spray resistance.

Supplementary Note: The service environment is crucial. Coastal high-salt-spray areas, industrial zones with acid-alkali exhaust gas, and humid rainy regions will accelerate plate corrosion, shortening the service life by 30%–50%. By contrast, dry inland areas can extend the service life.

II. Selection Method of Color Coated Steel Sheets

Screen by demand priority and focus on the following 5 key points:

Clarify the Service Scenario

Temporary buildings (prefabricated houses): Choose ordinary cold-rolled base plate + PE coating for cost-effectiveness.
Industrial workshops/warehouses: Opt for hot-dip galvanized base plate (zinc coating weight ≥80g/㎡) + SMP coating to balance cost and durability.
Coastal/highly corrosive environments: Select galvalume base plate + PVDF coating. Ensure the coating thickness is ≥25μm and fluorine content is ≥70%.

Verify Base Plate Quality

Prioritize hot-dip galvanized/galvalume base plates and avoid cold-galvanized ones (prone to rusting).
Check the zinc coating weight: ≥60g/㎡ for civil use, ≥80g/㎡ for industrial use, and ≥120g/㎡ for coastal areas.

Distinguish Coating Processes

Coating Type	Advantages	Applicable Scenarios
PE (Polyester)	Rich color options, low cost	Civil buildings in dry inland areas
SMP (Silicone-modified Polyester)	Better chalking resistance and weather resistance than PE	Industrial workshops
PVDF (Polyvinylidene Fluoride)	Excellent corrosion resistance, UV resistance and scrub resistance	Coastal/highly corrosive/high-end buildings

Inspect Appearance and Details

Surface: The coating should be uniform without bubbles, scratches or missed coating areas, and the color should be consistent.
Edges: The cutting surface should be burr-free, and the base plate should be free from oxidation and rust.
Certification: Prefer products with ISO 9001 certification and SGS salt spray test report to ensure qualified coating adhesion.

Match Plate Profile and Thickness

For roofing: Choose plates with wave height ≥30mm to enhance load-bearing capacity and drainage performance, with base plate thickness ≥0.4mm.
For wall cladding: Flat or small-wave profile plates are acceptable, with base plate thickness ranging from 0.3mm to 0.4mm.