Galvanized aluminum-zinc coil

Product Standard

Domestic standard: Primarily follows GB/T 2518-2019, “Continuous Hot‑Dip Galvanized Steel Sheet and Strip.” This standard specifies the classification, dimensions, external appearance, weight, technical requirements, test methods, inspection rules, packaging, marking, and quality certificates for continuous hot‑dip galvanized steel sheet and strip, and applies to products with a thickness of 2.0 mm or less.
International Standard:
ASTM A653/A653M-23, “Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Electrogalvanized),” applies to commercial‑grade and structural‑grade continuous hot‑dip galvanized steel sheet and strip. It specifies requirements for chemical composition, mechanical properties, dimensions, shape, weight, zinc coating weight, zinc coating adhesion, and zinc coating appearance.
BS EN 10346:2015, “Continuous hot‑dip galvanized flat steel products for cold forming — Technical delivery conditions,” specifies the technical requirements for continuous hot‑dip galvanized sheet and strip, including dimensions, shape, weight, zinc coating mass, zinc coating adhesion, and zinc coating appearance. It is applicable to a wide range of industries, such as construction, automotive, and home appliances.

Intended Use

Construction industry: Used to manufacture corrosion‑resistant roofing panels, roof grilles, steel‑structure purlins (C‑ and Z‑shaped steel), light‑steel framing members, ceiling suspension tracks, and more. It is also suitable for constructing ventilation ducts and exterior architectural finishes, effectively resisting environmental degradation and extending the service life of buildings.
Automotive manufacturing: Primarily used to produce corrosion‑resistant components for passenger cars, such as body structural parts, chassis components, and door frames, thereby enhancing the vehicle’s overall corrosion resistance and safety, and improving its quality and service life.
Home appliance industry: It can be used to manufacture appliance housings, such as those for refrigerators, washing machines, and air conditioners, as well as residential chimneys and kitchenware. Its excellent formability and corrosion resistance meet the aesthetic and durability requirements of home appliance products.
Agriculture, animal husbandry, and fisheries: Used as grain storage and transportation equipment, freezing and processing tools for meat and aquatic products, and aquaculture facilities, it can maintain stable performance in humid and mildly corrosive environments, preventing equipment from rusting and sustaining damage.
Other applications: In commerce, it is primarily used as a storage and transportation container and packaging material; it can also be employed in the manufacture of steel pipes, such as greenhouse pipes, water‑supply pipes, heating pipes, and gas‑transportation pipes; furthermore, it is utilized in the processing of various metal products, including the fabrication of structural components and hardware fittings.

Product Introduction

Galvanized strip steel is produced by coating cold-rolled or hot-rolled, long and narrow steel strips with varying thicknesses of zinc or a zinc alloy.
Production process: First, the full‑coil strip steel is pickled to remove surface contaminants, resulting in a bright, clean surface. It is then subjected to galvanizing via hot‑dip galvanizing, continuous hot‑dip galvanizing, or direct galvanizing. In hot‑dip galvanizing, after pickling, the strip is rinsed in a bath containing an aqueous solution of ammonium chloride, zinc chloride, or a mixture of both, and then transferred to a hot‑dip galvanizing bath. For continuous hot‑dip galvanizing, the strip is rinsed in a similar bath following pickling, passed through a continuous annealing furnace, and then immersed in a galvanizing bath. Direct galvanizing involves passing the pickled strip directly through a continuous annealing furnace before immersing it in a galvanizing bath.
Product features: Hot-dip galvanizing offers advantages such as a uniform coating, strong adhesion, and a long service life. During the process, the steel strip substrate undergoes complex physical and chemical reactions with the molten zinc bath, forming a tightly structured, corrosion‑resistant zinc‑iron alloy layer. This alloy layer is integrally bonded to both the pure zinc layer and the steel strip substrate, resulting in exceptional corrosion resistance. In addition, galvanized steel strip exhibits excellent formability, allowing it to be stamped, bent, welded, and otherwise processed to meet the shaping requirements of various products.

National Standard

GB/T 2518-2019 “Continuous Hot-Dip Galvanized Steel Sheet and Strip” is an important national standard for galvanized strip steel. The following are some of its key provisions:
Dimensions, Shape, and Permissible Deviations: Specifies the nominal thickness and nominal width of galvanized strip steel, as well as the permissible deviations for thickness, width, and length. For example, the allowable deviation in thickness varies depending on the nominal thickness and nominal width, while the allowable deviation in width is governed by specific provisions corresponding to different width ranges.
Technical requirements cover chemical composition, mechanical properties, zinc coating weight, zinc coating adhesion, and surface quality. The chemical composition must comply with relevant standards to ensure the product’s mechanical performance and corrosion resistance; mechanical properties such as tensile strength, yield strength, and elongation must meet specified standards; the zinc coating weight is typically expressed in grams per square meter and shall satisfy applicable requirements to guarantee both corrosion resistance and cost-effectiveness; zinc coating adhesion must conform to standard specifications to prevent delamination during fabrication and service; and surface quality must be smooth, even, and free of visible defects to ensure aesthetic appeal and corrosion resistance.
Test methods: The specific procedures for conducting various performance tests on galvanized strip steel have been clearly defined, including methods for chemical composition analysis, mechanical property testing, determination of zinc coating weight and adhesion, and visual inspection, among others.
Inspection Rules: These rules specify the classification of product inspections, batch‑forming criteria, sampling sizes, and acceptance criteria, thereby ensuring that product quality meets the relevant standards.
Packaging, Marking, and Certificates of Quality: The packaging methods, marking requirements, and the information to be included in certificates of quality for galvanized strip steel have been standardized to facilitate product transportation, storage, and identification, while also providing users with documentation attesting to product quality.