GM 9540P-2010 ACCELERATED CORROSION TEST.pdf

GENERAL MOTORS ENGINEERING STANDARDS Materials and Processes- Procedures
ACCELERATED CORROSIONTEST
GM9540P
SUPERCEDED
Do Not Use on New Programs; Replaced by GMW14872
1 SCOPE. This procedure describes an accelerated labo-
durations C and D or any modified tcst arc to bc used for vali-
ratory corrosion test method to evaluate assemblies and dation and dcvclopmcnt purposes
componcnts. The test procedure prorides a combination of 1.1]he test method is comprised of 1 25%(0.9 sodium
cyclic conditions( salt solution, various temperatures, humid
chloride 0.1%/ calcium chloride and 0.25% sodium bicarbon
ity, and ambient environmen to accelerate metallic corrosion. a) salt mist applications coupled. with high temperature and
he proccdurc is affective for cvahuating a varicty of corrosion high humidity and moderately high temperature dry off. It
mechanisms, such as gencral, galvanic, crevice ctc. The tcst requires a 16 h work day or an automatic cling test chamber
duration can be individually tail
orcd to achiev anv (csitcd
lcvcl of corrosion cxposurc
IMPORTANT: Enginccring drawings and matcrial specifica-
tions that reference this test procedure must specify the test
duration, (A, B, C. or D)or the number of test cycles as indi
Also, synergistic cffects uc to temperature, mcchanical and cated in Iable 1.(Example. Gm95401'iest uration B )In
electrical cycling can be comprehended by this test. See
addition, the criteria for making pass/fail determinations must
Appendix A for typical modifications
be specitied. Test durations A and B3 can be used for quality
conttol and validation proccdutcs as approprate. Longcr test
NOIL: Iest durations
A and B can be used as both QC tests durations(C and 1))and tcsts involving modifications are to be
and validation tests depending on the purposc of the test. T'est used for vaidation purposes on
TABLE 1-CYCLES(APPROXIMATE) FOR TARGET MASS LOSS
Test D
B
D
Tcst Mcthod
8 Cycles
16 Cycles
40 Cycles
80 Cycles
muons Rc
TABLE 2-MASS LOSS TARGET RANGES, mg"(AT THE END OF TEST
Initial Coupon Thickness
Test Duration
Inin
B
C
D
828-1228
496-1896
3210-3810
6038-663
1/16
874-1274
1574-1974
3378-3978
3.18
965-1375
1731-2131
3712-4.312
6957-7557
6.35
1/4
1147-1547
2043-2443
4379-4979
8178-8778
Th m l a h t rion u m li n Ta 1 ab and aa h t an st ou n
Modifications to the test may or may not attain equivalent levels of mass loss
NOTF 1: A cycle is made up of the daily events or test inputs 3 EQUIPMENT AND TEST MATERIAL. 3.1 THST
prescribed in I'ablc 4. A cycle normally requires 1 day to com- l QUIPMIENI
plete. The test duration is dictated by the number of test cycles
3. 1. 1 Fog I lumidity Cabinet. The humidity cabinet shall be
as specifed by GM44651 and 'Iable
Water foo or visible
NOTE 2 A phasc is made up of a predetermined number Of
rater droplets on parts-continuous after equilibrium is
cycles, 8 cycles constitute 1 phase
rcachcd
NO; 3: he coupon mass loss aues shoun in able 2 are 3. 1.2 Salt Mist plication. The salt mist solution shall be
used to verify that the correct amount of corrosion has been
produced by the test
or cxample,