ASTM B117 Salt Spray Test Procedure

ASTM B117 describes the apparatus, procedure, and conditions required for the salt spray (fog) testing environment. The practice provides a controlled corrosive environment that has been utilized to produce relative corrosion resistance information for specimens of metals and coated metals exposed in a given test chamber.

ASTM B117 Salt Spray Test Procedure

In ASTM B117 testing, the apparatus for the salt spray (fog) exposure includes a fog chamber, a salt solution reservoir, a supply of suitably conditioned compressed air, one or more atomizing nozzles, specimen supports, heating provision for the chamber, and control mechanisms.

Prior to testing, paint or nonmetallic coated specimens should not be cleaned or handled excessively. If it is desired to determine the development of corrosion from an abraded area in the paint, a scratch or scribed line is made through the coating with a sharp instrument to expose the underlying metal. Each specimen shall be placed to permit unencumbered exposure to the salt spray fog. Care should be taken to avoid the dripping of salt solution from one specimen to another.

The salt solution shall be prepared by dissolving 5±1 parts by mass of NaCl in 95 parts of water. The pH of the salt solution shall be such that when atomized at 35°C the collected solution will be in the pH range from 6.5 to 7.2. The exposure zone of the salt spray chamber shall be maintained at 35±2°C.

Unless otherwise specified in the specifications covering the material or product being tested, the test shall be continuous for the entire duration of the test period. The period of exposure shall be as designated by the specification covering the material or product being tested.

Unless otherwise specified in the specifications covering the material or product being tested, specimens shall be treated as follows at the end of the test: the specimen shall be carefully removed. Specimens may be gently washed or dipped in clean running water not warmer than 38°C to remove salt deposits from their surface and then immediately dried. A careful and immediate examination shall be made as required by the specification covering the material or product being tested.

Industrial application

1.  Paint and Coatings

2.  Automotive

3.  Aerospace

4.  Military applications