Description / Abstract:
Introduction
Note: Nothing in this standard supercedes
applicable laws and regulations.
Note: In the event of conflict between the
English and domestic language, the English language shall take
precedence.
Purpose. This standard is an aggressive
characterization of the susceptibility of a plastic component to
Stress Corrosion Cracking. It accomplishes this by exposing it to
different artificial environments with the presence of chlorides.
It requires that an appropriate stress level be imparted on the
component. The tests are not a direct comparison to field exposure
and can only indicate whether the component is susceptible to
attack at the stress level that was induced on it.
The two chlorides identified in this standard are calcium
chloride and zinc chloride. Calcium Chloride is a common chemical
used in de-icing solutions and gravel road dust control. Zinc
Chloride only occurs from a reaction of zinc and other chlorides
(e.g., sodium or calcium).
It is not recommended to directly fasten any plastic component
which is susceptible to chloride stress corrosion cracking directly
to a zinc surface.
Applicability. Testing is recommended for
certain polymers (as defined in Table 1) exposed to the underbody
and lower underhood atmosphere in critical applications. If the
polymer is not identified within the table, GM Materials
Engineering shall be consulted to determine the appropriate
disposition.