Even the most durable or permanent items can at some point deteriorate. That doesn’t mean these qualities should be ignored. However, the ability to remain unchanged is a property that should be discerned and actively endeavored to maintain. ASTM B117-18: Standard Practice for Operating Salt Spray (Fog) Apparatus provides guidelines for an apparatus that is helpful in discerning corrosion resistance information.
What is Corrosion?
Corrosion is the decay of a material due to the chemical reaction with its environment. When a significant number of atoms on a metallic surface are oxidized, general corrosion occurs. The most familiar corrosion product of iron is rust.
What Are the Effects of Corrosion?
Corrosion can compromise the safety of human life. Numerous tragedies have resulted due to corrosion. For example, in 2017, a ride collapsed at an Ohio state fair, killing one and injuring seven others. The manufacturer cited corrosion as the reason for ride failure. In 1983, the Mianus River Bridge collapsed, killing three people and seriously injuring others. The bridge was only 25 years old at the time. Investigations found that the support pins in the bridge had corroded.
Corrosion can also be expensive. A NACE International study conducted from 1999 to 2001 found that corrosion directly cost the US $276 billion annually. This of course does not take into account the indirect cost of corrosion. According to the same NACE study, the indirect cost was conservatively estimated to be a total of $552 billion. Clearly, corrosion demands consideration.
What is the Standard Practice for Operating Salt Spray (Fog) Apparatus?
ASTM B117-18 covers the apparatus, procedure, and guidelines to create and sustain the salt spray (fog) test environment. It is important to note that the standard does not prescribe the interpretation of the results. It also does not prescribe the exposure periods to be used for the specific products or the type of test specimen.
ASTM B117-18 delivers a controlled corrosive environment that can be used to gather information on relative corrosion resistance for metal specimens and coated metals exposed in a fixed test chamber.
The referenced documents in ASTM B117-18 include:
- ASTM B368: Test Method for Copper-Accelerated Acetic Acid-Salt Spray (Fog) Testing (CASS Test)
- ASTM D609: Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish, Conversion Coatings, and Related Coating Products
- ASTM D1193: Specification for Reagent Water
- ASTM D1654: Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments
- ASTM E70: Test Method for pH of Aqueous Solutions With the Glass Electrode
- ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method G85 Practice for Modified Salt Spray (Fog) Testing
ASTM B117-18: Standard Practice for Operating Salt Spray (Fog) Apparatus is available on the ANSI Webstore.