Cyclic corrosion testing of materials and components in automotive construction

Introduction

A specification created jointly by the automotive, steel and aluminium industries.

Developed to provide a standard for the cyclic corrosion testing of new materials and coatings within the automotive industry, the intention is that this test will eventually replace the older VDA 621-415 test.

The function of the standard is to provide an accelerated test process for the assessment of corrosion behaviour of components and of corrosion protection provided by coatings.

The test is especially suitable for assessment of the corrosion creep around defects in coatings, for example flanged areas or gaps and unpainted surfaces

Conditions

Test specimens are placed in an enclosed chamber that includes equipment for cooling, heating and for pressure compensation, and positioned at an angle of 65° to 75° to the horizontal with the side to be tested uppermost. The salt spray phase is performed with a 1% solution of sodium chloride, (pH 6.5 to 7.1) and falls out onto the specimens at a rate of 2.0 to 4.0ml/80cm²/hour.

Method

The test duration is to be determined on a case by case basis depending on the time required to draw conclusions on the corrosion behaviour. 

A full test cycle lasts 7 days and consists of:

• 3 times = 24 hours cycle A without freezing phase, with 3 hours salt spray phase
• 3 times = 24 hours cycle B without freezing phase, without salt spray including assessment of samples
• 1 time = 24 hours cycle C with freezing phase, without salt spray.

The typical test duration is six full test cycles. (6 Weeks)

Typical Application

This method generates reproducible patterns which directly compare with the results obtained in a real world automotive environment, especially for steel, galvanised steel and aluminium.

If you would like further information please call our experienced team on 01827 318040 or email sales@ascott-analytical.com