How do you test for intergranular corrosion?
Streicher Test (ASTM A262 Practice B) Generally used for stainless steel and nickel alloys, the Streicher test involves boiling the specimen in a Ferric Sulfate – Sulfuric Acid solution for 24-120 hours and evaluating the results. The level of corrosion is determined by mass loss.
What is intergranular testing?
Intergranular Corrosion (IGC) or Intergranular Attack (IGA), is an efficient test for screening a material’s corrosion resistance under certain conditions.
What is intergranular corrosion example?
Stainless steels and weld decay sensitization are the best examples of intergranular corrosion. Grain boundaries that are rich in chromium elements will precipitate lead. This makes the boundaries very vulnerable to corrosion attacks in various electrolytes.
What is the mechanism of intergranular corrosion?
Intergranular corrosion is caused by Microsegregation of impurities and alloying elements on the grains boundaries. The driving force of intergranular corrosion is the difference between the Electrode potentials of the grain boundary and the grain itself, which form a galvanic cell in presence of an electrolyte.
Can you see intergranular corrosion?
Intergranular corrosion can lead to catastrophic failure in most process equipment if correct material and proper heat treatment haven’t been used during the fabrication stage. There are many types of corrosion damage, such uniform corrosion and pitting corrosion that people can readily see with the naked eye.
Where is intergranular corrosion found?
the grain boundaries
Intergranular corrosion is localized attack along the grain boundaries, or immediately adjacent to grain boundaries, while the bulk of the grains remain largely unaffected.
What is transgranular and intergranular corrosion?
Intergranular stress corrosion cracking (IGSCC) – Cracks propagate along the grain boundaries. Transgranular stress corrosion cracking (TGSCC) – Cracks run through the individual grains.
Where does intergranular corrosion occur?
Can you repair intergranular corrosion?
Fortunately, heat treatments can often resolve the issue and return the metal’s structure to a near-original state. In some cases, solution-annealing (also known as quench-annealing or solution-quenching) is an effective means of reversing intergranular corrosion damage in austenitic stainless steels.
What is critical pitting temperature?
Critical pitting temperature (CPT) refers to the degree of hotness or coldness of an environment that prompts the onset of pitting and/or crevice corrosion in a metallic substrate. Pitting corrosion is a form of localized corrosion that attacks in the form of spots or pits.