Neutral salt spray test — Results of an international interlaboratory test and conclusions for practical application (Edition 1, 2026)

Abstract
The objective of this document is to conduct a neutral salt spray test in accordance with ISO 9227. The test is a proven method for assessing the corrosion protection of coatings of components such as bolts. For this reason, two coating variants were chosen for conducting the tests on hexagon bolts with a size of M6 × 50. The bolts were examined at specified points in time and the time of occurrence of grey veil, white rust and red rust was documented. The corrosivity of the salt spray was determined by means of two methods and also documented in an evaluation form. These two methods are the assessment of the mass loss of an uncoated steel panel as specified in ISO 9227 as well as the determination of the time until appearance of red rust on hot-dip galvanized steel panels in accordance with ISO 4042 and ISO 10683.

The processing steps are specified in detail in a manual that was provided to the test participants. If followed precisely, these instructions allow for a comparative analysis of the results from the individual labs and make it possible to determine the reproducibility of the salt spray test. Another objective is to compare the two methods used to determine the corrosivity of the salt spray in order to establish the suitability of these methods by comparing the corrosion assessment results obtained for the bolts. In addition, the normative operating parameters (temperature in the test cabinet, collection rate, pH and density or NaCl concentration of the solution collected) were documented for every inspection date in order to ascertain whether there is any correlation with the results of the corrosion assessment performed on the bolts.

General information
Status : Published
Publication date : 2026-02
Stage : International Standard published
Edition : 1
Number of pages : 38

All standards

ISO/IEC 29167-10:2026

ISO 29061-1:2026

ISO/IEC 23090-28:2026

ISO 1825:2026

ISO/TR 25326:2026

ISO/TR 4550:2026

ISO/TR 19852:2026

ISO 15883-6:2026

ISO 20500-5:2026

ISO 4029:2026

ISO/IEC 18000-65:2026

ISO 12940-1:2026