When using stainless and duplex steels, ASTM G48 is widely used to ensure the quality of the material and resistance to pitting and crevice corrosion. ASTM G 48 is a relatively severe test, but lack of definition in the standard can lead to variation of data. We follow a standard practice we have developed to minimize these variations and provide consistent data. However, the G48 test is meant for ranking only and not as designed for determining a corrosion rate over time.
ASTM G48 Methods A-F: Which test do I need?
Pitting and crevice corrosion are common corrosion modes for stainless steels; the G48 standard includes 6 separate methods, begging the question: which one do you need? The answer is: it depends. There are several factors that can influence the selection of methods; we can help you with this part of the process as well. The available pitting and crevice testing methods include:
Method A—Ferric chloride pitting test.
Method B—Ferric chloride crevice test.
Method C—Critical pitting temperature test for nickel-base and chromium-bearing alloys.
Method D—Critical crevice temperature test for nickel-base and chromium-bearing alloys.
Method E—Critical pitting temperature test for stainless steels.
Method F—Critical crevice temperature test for stainless steels.
The ASTM G 48 Standard:
The ASTM G 48 Standard is entitled “Standard Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chloride Solution” and is widely used to analyze stainless, duplex, and nickel-based alloys.