After over two years service in the 'snow belt', class 12.8 bolts in GM 'A' car rear suspensions began to fail, leading to the recall of 6.4 million cars. Analysis of the failures showed that the cause was corrosion induced hydrogen assisted cracking. The long delay before failure resulted from a decarburized surface through which corrosion had to penetrate before a crack could propagate. The fracture morphology of the field failures was duplicated in laboratory salt spray tests. This type of testing also showed that hardness was the principal factor affecting durability in a corrosive environment. (Wassmann)
Delayed fracture of class 12.8 bolts in automotive rear suspensions
Verspaeteter Bruch von Bolzen der Gueteklasse 12.8 in Hinterradaufhaengungen von Automobilen
SAE-Papers ; 1-6
1982
6 Seiten, 7 Bilder, 6 Quellen
Aufsatz (Konferenz)
Englisch
Delayed Fracture of Class 12.8 Bolts in Automotive Rear Suspensions
Kraftfahrwesen | 1982
|Engineering Index Backfile | 1923
Nissan's twist on rear suspensions
Online Contents | 1994