Short answer
On a coated carbon steel fitting, the coating is part of the resistance to the external environment; it does not replace the base material or the connection geometry. The coating type and test conditions must be evaluated together with the actual field exposure.
Technical explanation
Corrosion can cause material loss; damage to the coating on the outer surface is examined from this perspective. A laboratory test duration given for a coating is not directly a field life in years. Threads, wrench contact areas and clamp zones can see different local conditions. The same color or gloss does not indicate the same coating system. When the material or coating changes, the assembly method and the manufacturer's compatibility information are also checked.
Topic-specific checkpoints
| Item | Description |
|---|---|
| Base material | Carbon steel grade and product |
| Coating | System and manufacturer designation |
| Test | Method; not equal to field life |
| Damage location | Thread, surface, wrench and contact areas |
How to evaluate it in practice
In the quotation, ask for the actual coating system and product material instead of a broad description such as 'galvanized'. If there is a test report, record the test method, the acceptance criterion and which product was tested. State field conditions such as a seaside location or chemical washing separately. Do not repaint a worn coating and treat the assembly as having passed a technical check. If there is corrosion on the sealing surface or the thread, the decision on the part should be made after safe isolation, through a competent assessment.
Original editorial recommendation; not a clause of a standard.
Frequently asked questions
Can salt spray test hours be converted directly into years of service?
There is no general, reliable direct conversion. Test conditions and actual field exposure differ.
Source coverage
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S017
Parker Safety Guide, Publication 4400-B.1 Parker Hannifin · accessed 2026-10-20 PDF page 4; 5.1 Maintenance Programme, 5.2 Visual Inspection, 5.3 Other Inspection and 5.6 Hose Inspection and Failure | PDF page 2; 2.5 Fluid CompatibilityPDF page 2; 2.8 Routing, 2.10 Mechanical Loads and 2.11 Physical DamagePDF page 3; 3.1 Component Inspection, 3.2 Hose and Fitting Assembly and 3.3 Related Accessories | PDF page 2; 2.5 Fluid Compatibility
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S098
Materials of Construction Swagelok · accessed 2026-10-19 Descriptions of corrosion mechanisms and material selection; quantitative limit tables not imported