Cyclic Corrosion Test — ASTM G85 / SAE J2334 / VDA 233-102

What Is Cyclic Corrosion?

The cyclic corrosion test is an accelerated corrosion test in which wetting, drying, humidity, and sometimes low-temperature stages are applied in cycles instead of continuous salt fog. It gives results closer to the actual atmospheric corrosion mechanism.

Purpose of Cyclic Corrosion

The purpose is to assess the effect of wet-dry transitions, which continuous salt fog does not represent, and to provide better correlation with field behaviour.

Which Products Is Cyclic Corrosion Applied To?

Automotive body and chassis components
Painted and coated sheet metal parts
Fasteners
Outdoor building components

In Which Sectors Is Cyclic Corrosion Used?

AutomotiveElectric VehicleBatteryPlasticsRubber

Standards Related to Cyclic Corrosion

ASTM G85modified salt fog (cyclic) test test
SAE J2334cyclic laboratory corrosion testing test
VDA 233-102cyclic corrosion testing in automotive test
ISO 16701cyclic corrosion test test
ASTM D5894

Cyclic Corrosion Conditions

Cycle structure: The order and duration of the wetting, drying and moisture stages defined in the specification
Solution: Dilute electrolyte or NaCl solution according to specification
Temperature: It varies depending on the stage; some specifications include a low temperature phase
Number of cycles: Defined in specification (e.g. 30, 60, 90 cycles)

Equipment for Cyclic Corrosion

Programmable cyclic corrosion chamber
Solution preparation and spray system
Humidity and temperature control system
Data logging system

Sample Requirements for Cyclic Corrosion

Generally at least three specimens
Pre-damage by scribe or stone-chip impact may be applied per the specification
Cut edges must be masked
The coating system and thickness must be recorded

Duration of Cyclic Corrosion

Depends on the number of cycles. One cycle typically takes 8 – 24 hours; a 60-cycle programme takes weeks.

Cyclic Corrosion Procedure

1Samples are prepared and pre-damage applied if required.
2The cycle programme from the specification is loaded into the chamber.
3Wetting, drying and humidity stages are run in sequence.
4Interim observations are made at defined cycle intervals.
5Once the programme is complete, samples are washed and evaluated.

Cyclic Corrosion Acceptance Criteria

The acceptance criterion is defined in the specification; usually given as maximum corrosion spread around the scribe or maximum under-film corrosion width.

Evaluation of Results

Scribe spread, blistering and base-metal corrosion are measured. Cyclic results are not comparable with continuous salt spray.

Cyclic Corrosion Report

Applied standard and cycle programme
Solution composition and stage durations
Number of cycles and interim observations
Corrosion spread measurements
Photographs

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

Automotive OEM corrosion specifications (VDA, SAE)

Otomotiv Testleri — What Does This Testing Field Cover?

The section below describes the field that the Cyclic Corrosion test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Automotive testing shows that a component keeps working under conditions representing the loads it will meet over the life of the vehicle. A vehicle is not a single product but an ENVIRONMENT: vibration, temperature cycling, salt water, stone impact, electrical transients and electromagnetic noise are all present at the same time and for years.

What distinguishes this family is that VEHICLE MANUFACTURER SPECIFICATIONS sit on top of the standards. ISO and SAE publications establish the common ground; but Volkswagen, BMW, Ford, Stellantis, Toyota and Renault define different severity levels, additional tests and different acceptance criteria in their own specifications. For a component, the phrase "complies with automotive standards" is not sufficient on its own; which manufacturer's specification, and which revision of it, must be answered.

The family carries three separate processes together and they are often confused. Homologation covers the type approvals a vehicle needs to enter traffic and runs under state authority. Supplier approval means passing the vehicle manufacturer's own quality and testing requirements and is a commercial relationship. The third is design verification: the engineering team demonstrating that its own design meets its targets.

At component level the test plan is built around the LOCATION OF USE. A module in the engine bay and a module in the boot do not go through the same temperature and vibration profile; a component inside a door and one in the roof console do not see the same water and dust exposure. The ISO 16750 series is the common framework for this location-based approach.

The shift to electric vehicles has reshaped the field. High-voltage safety, insulation coordination, battery safety, charging interface conformity and the electromagnetic behaviour of high-voltage components have been added to the classical automotive test set. In a quiet vehicle, acoustic and vibration expectations have changed too; sounds once masked by the combustion engine are now audible.

The quality system side cannot be separated from testing in this field. A manufacturer under IATF 16949 presents test results in the PPAP file; measurement system analysis, process capability study and the control plan stand around the test report. A single good result is not enough — the process must be shown to be able to repeat it.

Method groups in this field

Environmental and climatic
Temperature cycling, thermal shock, damp heat, salt spray, dust and water ingress (IP), solar radiation. Severity levels vary with the mounting location.
Mechanical
Sine and random vibration, shock, mechanical loads, fastener torque and durability cycles.
Electrical
Supply voltage variations, transients (ISO 7637), reverse polarity, overvoltage, short circuit and sleep current measurements.
EMC
Component emissions (CISPR 25), radiated and conducted immunity (ISO 11452 series), electrostatic discharge (ISO 10605).
Materials and emissions
Odour, fogging and VOC emissions from interior materials; flammability; UV ageing; coating durability and stone impact.
Functional safety and cyber security
Functional safety evidence under ISO 26262 and cyber security engineering under ISO/SAE 21434; these are tied to regulation through UNECE R155 and R156.

Commonly confused in this field

An automotive report without a specification reference is not accepted in the supply chain; which OEM specification and revision was applied must be stated.
Type approval and supplier approval are different processes. A component with E-Mark approval is not thereby considered to have passed the OEM's own acceptance tests.
A result obtained on a prototype does not carry over to series production; PPAP is done with series production parts.
On the EMC side, measuring emissions alone is incomplete; immunity is a separate body of work and is more critical in a vehicle.
On electric vehicle components, high-voltage safety is a distinct competence; classical 12 V test infrastructure is not sufficient.

Which decisions these results support

Supplier component approval and the PPAP file
UNECE type approval and E-Mark marking
Design verification and durability evidence
Root cause analysis of field complaints and warranty returns
Assessing the impact of a design or supplier change

Related Tests

Frequently Asked Questions About Cyclic Corrosion

Why is the cyclic corrosion test preferred?

Continuous salt spray does not include wet-dry transitions and can mispredict field behaviour for some coating systems. Because cyclic tests include a drying stage, they correlate better with actual atmospheric corrosion.