Cyclic Corrosion Testing for Automotive Manufacturers
JASO M 609-91, published in 1991, is a widely-used standard for testing automotive steel and coatings for corrosion resistance. Developed by the Japanese Automotive Standards Organization (JASO), this test method was one the first wave of automotive cyclic corrosion tests. The test puts cold-rolled, hot-rolled, and coated steel sheets through rigorous cycles of salt spray, drying, and wetting phases with rapid transitions to accelerate corrosion and deliver reliable performance data.
A major revision to JASO M 609-91, including drastically different test cycles, was published in 2024. Q-Lab will soon offer guidance and content related to this significant development in Japanese automotive testing.
Test Parameters
The test conditions used in JASO M 609-91 are designed to simulate the corrosive environment that automotive applications will face. The test cycle lasts 8 hours and consists of three steps:
- Salt Fog (2 hours)
- Temperature: 35 °C
- Concentration of salt: 5% NaCl (conforms to JIS Z 2371)
- Drying (4 hours)
- Temperature: 60 °C
- Relative humidity: 20-30% RH
- Wetting (2 hours)
- Temperature: 50 °C
- Relative humidity: 95% RH
For in-depth information on the test conditions of JASO M 609-91, customers may log into their Q-Portal account.
Transition Times for JASO M 609-91
Notably, JASO M 609-91 specifies relatively short transition times between the fog, dry, and wet phases. The transitions between Fog and Dry, and between Wet and Fog, must be completed within 30 minutes. The transition between Dry and Wet is allotted only 15 minutes. The standard's authors intended these fast transition times as a technique to mitigate variability between tests, at a time when relative humidity control in corrosion test chambers was not available.
These demanding, rapid transition times require the use of the Q-FOG CRH tester's Rapid Ramp Heater accessory, which was designed specifically to meet the conditions of this test. For in-depth information on the test conditions of JASO M 609-91, customers may log into their Q-Portal account.
Why Test for JASO M 609-91
Automotive companies use JASO M 609-91 because it delivers fast results on potential corrosion resistance failures that can be compared to decades of historical laboratory test data. Although modern corrosion tests may offer more realistic testing conditions with controlled relative humidity, JASO M 609-91 represented a breakthrough in its time, combining Fog, Dry, and Wet conditions into a single cyclic test tailored to automotive manufacturers. For companies looking to qualify and supply to major Japanese automakers, performance of JASO M 609-91 is critical.
Pros and Cons of JASO M 609-91
- Cyclic testing
- JASO M 609-91 includes salt fog, dry, and humid phases, simulating real-world conditions changes much better than simple continuous salt spray or wet/dry techniques.
- Industry Recognized Test Method
- This test method is widely accepted by many major automotive manufacturers, and is a requirement for many Japanese OEMs as well as their global suppliers
- Comprehensive Testing
- JASO M 609-91 tests for multiple failure modes (not just uniform corrosion)
- Evaluates both substrate and coating performance
- Lack of controlled RH
- Although JASO M 609-91's concept of minimizing transition times to improve repeatability was admirable at the time, modern test chambers and cycles offer much greater consistency with relative humidity control.
- The rapid, uncontrolled transitions in JASO M 690-91 result in materials spending very little time at intermediate RH values, where actual products in fact spend most of their life.
- Performance difficulty
- The very rapid transitions of this test make it very difficult for most test chambers to perform. Fortunately, the Q-FOG CRH with Rapid Ramp Heater has the power to effect fast changes between steps.
How Q-Lab Can Help
Q-FOG Cyclic Corrosion Test Chambers
The Q-FOG CRH model tester with Rapid Ramp Heater is specially designed to deliver the rapid step transitions called for in JASO M 609-91 and other related automotive testing standards.
Testing Services
Q-Lab offers a full range of ISO 17025 accredited laboratory testing services in our fully-equipped laboratories in Florida and Germany. We can perform everything from simple salt spray testing to modern automotive cyclic corrosion tests. Laboratory corrosion testing can be used for quality control, material certification, durability studies, and independent third-party verification.
Q-PANEL Standard Test Substrates
Q Lab’s CX-series mass-loss corrosion coupons ensure repeatability and reproducibility when performing laboratory corrosion testing. Although not required in JASO M 609-91, they can give some indication of repeatability of test performance.
More JASO M 609-91 Resources
Standards Tool
Review setup and performance information on key international and OEM test standards from ASTM, ISO, SAE, JIS, GB, and more.
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