Overview
ISO 1460:2020 specifies a standardized method for the gravimetric determination of the mass per unit area of hot dip galvanized coatings on ferrous materials. This international standard applies primarily to ferrous components with surfaces that have easily measurable areas, ensuring precise quality control in corrosion protection practices. By accurately assessing the mass of zinc coatings, manufacturers and inspectors can verify coating performance, durability, and compliance with industry requirements.
Key Topics
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Scope and Application
The standard targets hot dip galvanized ferrous materials where accurate surface area measurement is feasible. For complex or heavy samples that do not meet procedural criteria, alternative methods are recommended.
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Principle
The mass loss of a galvanized sample after dissolving the zinc coating with an inhibited acid solution reflects the coating mass. The sample is weighed before and after zinc removal to calculate mass per unit area.
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Stripping Solution
The solution consists of hexamethylenetetramine dissolved in concentrated hydrochloric acid, diluted with distilled water. It enables controlled dissolution of the zinc coating without damaging the base metal.
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Sampling and Preparation
Samples are degreased with organic solvents that do not attack the zinc coating, dried, and weighed with a precision better than 1% relative to the expected coating mass.
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Procedure
The galvanized sample is fully immersed in the stripping solution at room temperature until gas evolution ceases, indicating full coating dissolution. Following rinsing, drying, and possible brushing, the sample is reweighed, and surface area measurements are performed with an accuracy of 1%.
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Calculation of Mass per Unit Area
The mass per unit area (grams per square metre) is calculated by the difference in sample mass before and after zinc dissolution divided by the surface area:
[
\rho_A = \frac{(m_1 - m_2) \times 10^6}{A}
]
where (m_1) and (m_2) are masses before and after stripping and (A) is the surface area in square millimeters. Special formulas are provided for steel wire coatings.
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Reproducibility
The method demonstrates a reproducibility of about ±5%, accounting for variability between operators and testing conditions.
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Reporting Requirements
Test reports should include sample information, calculation methods, coating mass per unit area, any procedural deviations, observations, and test dates, referencing ISO 1460 for clarity.
Applications
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Quality Control in Galvanizing Plants
Enables manufacturers to verify coating thickness and uniformity for hot dip galvanized steel products such as wires, sheets, and structural components.
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Corrosion Protection Assessment
Ensures coatings meet protective mass standards critical for corrosion resistance in automotive, construction, and industrial applications.
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Product Specification Compliance
Allows buyers and suppliers to confirm coatings comply with technical and contractual specifications for galvanized ferrous materials.
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Research and Development
Supports the evaluation of new galvanizing processes and materials through precise coating mass measurements.
Related Standards
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ISO/TC 107
Technical committee responsible for metallic and inorganic coatings including hot-dip galvanizing processes.
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ISO 1461
Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods.
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EN 10240
Specification for hot dip galvanized coatings on fabricated iron and steel articles in Europe, often used complementary to ISO 1460.
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ISO 2178
Measurement of coating thickness by magnetic methods, sometimes used alongside gravimetric procedures for coating assessment.
Keywords: ISO 1460, hot dip galvanized coatings, gravimetric determination, mass per unit area, ferrous materials, zinc coating measurement, corrosion protection, galvanized steel testing, coating thickness standards.
