Galvanized Steel Acceptance Specifications and Standards
① Appearance Inspection: The surface of galvanized steel shall be smooth and uniform in color, free from visible defects such as zinc lumps, peeling, or missed coating. Taking a galvanized steel pipe as an example, carefully observe its surface. If localized areas are found without zinc coating, this constitutes missed coating, which is non-compliant; if raised bumps are observed, these are zinc lumps, also non-compliant.
② Zinc Coating Thickness Inspection: Different types and uses of galvanized steel have varying requirements for zinc coating thickness. For instance, galvanized angle steel for construction must achieve a specified average zinc coating thickness according to relevant standards. Professional tools such as magnetic thickness gauges are generally used for measurement. Multiple measurement points should be selected at different locations on the angle steel to ensure the data is accurate and reliable. If the measured thickness falls below the standard requirement, the corrosion resistance performance of the galvanized steel may be inadequate.
③ Adhesion Test: The zinc coating must exhibit good adhesion to the steel substrate. The grid test method can be employed: use a sharp blade to etch a grid of specific dimensions on the galvanized steel surface, apply adhesive tape, and then rapidly peel it off. Observe whether the zinc coating within the grid area shows signs of detachment. If the detachment area is excessive, it indicates poor adhesion of the zinc coating. In practical use, this could lead to zinc coating peeling, compromising the protective effect of the steel.
④ Dimensional Deviation Inspection: The dimensions of galvanized steel must comply with design requirements and relevant standard specifications. Taking galvanized steel sheet as an example, its thickness, width, length, etc., all have permissible deviation ranges. Use measuring tools such as calipers and micrometers to measure the sheet thickness multiple times at different locations, ensuring thickness deviations remain within the standard permissible range. For width and length, suitable measuring tools must also be used. If dimensional deviations exceed the specified range, it may affect the installation and use of the steel in engineering applications.
As a steel foreign trade company with more than a decade of industry experience, GNEE STEEL continuously optimizes its product lines and service processes, focusing on the production and processing of galvanized steel sheets, galvanized steel coils and other steel products. Currently, the team has more than 200 members and its service network covers more than 160 countries.
