ASTM B117 salt spray tests are carried out to obtain corrosion resistance information for specimens of metals and coated metals exposed to salt fog in a test chamber for a certain period of time (for further information please visit the page Standards at  www.astm.org).

In this particular case, the test was performed to determine to what extend the use of BoltShield® metal caps can help to prevent corrosion on bolts and nuts, rather than to test the corrosion resistance of caps, bolts and nuts themselves as metal parts. This test provides a comparison, in terms of corrosion, between bolts and nuts protected by BoltShield® caps and unprotected ones. Time of exposure to salt fog: 600 hours. Several combinations of bolted joints protected with BoltShield® caps have been tested.

After 600 hours of exposure of the specimens to salt fog, results document that bolts and nuts protected with BoltShield® caps show marginal corrosion only, as it can be seen in the picture above.

At the left: ASTM A193 B7 1" stud bolt + A194 gr 2H nut that remained exposed to salt fog throughout 600 hours. Both the bolt and the nut are completely corroded. At the end of the test, it was very difficult to unscrew the nut from the bolt.
At the right: ASTM A193 B7 1" stud bolt + A194 gr 2H nut that were protected by a BoltShield® cap TD Type. Here you can see that there is only marginal corrosion. The official Test Report along with all photographic attachments, dated May 22nd 2014, released by the technical laboratory that performed the test is available upon request.