From towering steel structures at construction sites to the gleaming exteriors of automobiles and everyday household appliances, one material plays a pivotal role—galvanized steel coils. But how do different countries regulate this essential material? What unique properties do various coatings impart? This article delves into the international standards, coating types, and applications of galvanized steel coils, offering a comprehensive understanding of this critical industrial material.

As a vital anti-corrosion material, the quality and performance of galvanized steel coils directly impact the longevity and safety of downstream products. Consequently, nations worldwide have established standards governing key parameters such as steel grades, dimensional ranges, coating compositions, and coating thicknesses. These standards not only ensure product quality but also facilitate smooth international trade.

Galvanized steel coils are primarily classified based on the following key characteristics:

• Application Fields: Depending on their use, galvanized steel coils can be categorized into types suited for cold forming, profile manufacturing, and steel structure fabrication. Different applications demand varying performance characteristics such as strength, ductility, and surface quality.
• Coating Composition: The anti-corrosion properties of galvanized steel coils largely depend on their surface coatings. Common coating materials include pure zinc (Z), zinc-iron alloy (ZF), zinc-aluminum alloy (ZA), aluminum-zinc alloy (AZ), and zinc-magnesium alloy. Each composition offers distinct corrosion resistance and suitability for specific environments.
• Coating Thickness/Weight: Coating thickness or weight is a critical indicator of a coil's anti-corrosion capability. Generally, thicker coatings provide better protection but also affect cost and processing performance.

The European standard EN 10346 and its Ukrainian counterpart DSTU EN 10346 serve as key references for galvanized steel coil production. These standards encompass multiple coating types, including:

• Zinc Coating (Z): The most traditional method, achieved by immersing steel strips in a molten zinc bath containing at least 99% zinc. The zinc layer forms a protective barrier against corrosive elements.
• Zinc-Iron Alloy Coating (ZF): Created through annealing after zinc immersion, this coating contains 8-12% iron. It offers superior adhesion to the base steel and enhanced resistance to delamination and pitting.
• Zinc-Aluminum Alloy Coating (ZA): With approximately 5% aluminum and trace rare-earth metals, this coating improves formability and corrosion resistance compared to pure zinc.
• Aluminum-Zinc Alloy Coating (AZ): Comprising 55% aluminum, 1.6% silicon, and the remainder zinc, this blend combines aluminum's dense oxide layer with zinc's sacrificial protection.
• Aluminum-Silicon Alloy Coating (AS): Containing 8-11% silicon, this coating excels in high-temperature resistance (up to 650°C) and chemical corrosion protection.

The standards categorize steel grades as follows:

• Low-Carbon Steels for Cold Forming (DX51D–DX57D): Classified by cold-forming performance, from bending quality (DX51D) to extra-deep drawing (DX57D).
• Structural Steels (S220GD–S550GD): Arranged by increasing yield strength (Rp0.2), used for light-gauge structural profiles.
• High-Strength Steels for Cold Forming (HX160YD, etc.): Also graded by yield strength, with prefixes indicating processing methods.
• Multiphase Steels (HDT450F, etc.): Sorted by minimum tensile strength (Rm0.2), with suffixes denoting microstructures like ferritic-bainitic (F) or dual-phase (X).

Coating weights under EN 10346 are expressed in grams per square meter (g/m²) for both sides combined. Minimum weights range from 100–600 g/m² depending on the coating type. The standard also classifies products by:

• Surface Quality: Original (A), improved (B), or premium (C) for decorative coatings.
• Surface Treatment: Chemical passivation (C), oiling (O), or combined methods.
• Surface Finish: Regular spangle (N) or minimized spangle (M).

Geometric dimensions and tolerances comply with EN 10143 standards.

The primary American standard for galvanized steel coils includes steel types such as:

• Commercial steel (CS types A–C)
• Forming steel (FS types A–B)
• High-strength low-alloy steel (HSLAS)
• Solution-hardened steel (SHS)

Coating weights range from 90–1,100 g/m² across grades G01–G360 (imperial) or Z001–Z1100 (metric). Dimensional tolerances follow ASTM A924/A924M.

Key standards in Commonwealth of Independent States countries include:

• GOST 14918: Covers cold-rolled galvanized sheets/coils for profiling, packaging, and metal goods. Classifications include:
  • Drawing capability: Normal, deep, or extra-deep
  • Coating thickness grades: Enhanced (570–855 g/m²), Class 1 (258–570 g/m²), or Class 2 (142.5–258 g/m²)
• GOST R 52246: Applies to low-carbon galvanized coils with zinc or zinc-iron coatings for profiled products. Specifications cover:
  • Application codes (01–06, 220–350)
  • Manufacturing precision levels
  • Coating weights (60–600 grades)
  • Surface finishes (regular/minimized spangle, iron-zinc)

Products under these standards range from 0.3–4.5 mm in thickness and 500–1,800 mm in width, with dimensional tolerances following GOST 19903/19904.