Oxalic Acid Test
Rapid screening by oxalic acid etching.
Overview
Detect susceptibility to IGC from processing or composition
Intergranular corrosion testing evaluates deterioration at grain boundaries—often due to carbide precipitation—so you can qualify material batches and confirm heat-treatment effectiveness across stainless-steel families.
ISO/IEC 17025:2017 accredited practices and reporting.
Austenitic stainless steels
ASTM A262 – Five intergranular corrosion methods
Applicable to austenitic grades; used for rapid screening of batches for susceptibility to IGC. The practice contains five unique tests.
Streicher Test
Corrosion test per practice B.
Huey Test
Multi-boil nitric acid exposure.
Strauss Test
Bend/exposure per practice E.
Copper Sulphate Test
Alternate medium with copper sulphate.
Ferritic stainless steels
ASTM A763 – Practices W, X, Y, Z
Detects susceptibility to intergranular attack in ferritic stainless steels; includes oxalic acid etch, ferritic sulfuric acid, copper sulphate–50% sulfuric acid, and copper sulfate–16% sulfuric acid tests, with microscopic examination (≈40×) and bend evaluations where specified.
Oxalic acid etch
Structure/attack indication via etching.
Ferritic sulfuric acid
Immersion test; microscopic exam ~40×.
CuSO₄ – 50% H₂SO₄
Copper sulphate + sulfuric acid procedure.
CuSO₄ – 16% H₂SO₄
Alternate concentration test; exam & bends.
“Test methods for qualifying ferritic stainless-steel products by detecting
susceptibility to intergranular corrosion (IGC).”
Duplex stainless steels
ASTM A923 – Intermetallic phases & heat treatment
Used to detect the presence of intermetallic phases in duplex stainless steels that can significantly affect corrosion resistance; supports verification of heat-treatment effectiveness.
Benefits
Why this testing matters
Material qualification
Screen batches and verify processing windows across stainless-steel families.
Performance assurance
Demonstrate compliance with industry requirements before deployment.
Actionable reporting
Clear acceptance criteria, micrographs, and decisions for QA/QC.
Get in touch
Talk to an expert
Send grade (Austenitic/Ferritic/Duplex), prior heat-treatment, and target practice. We’ll confirm specimen prep, exposure, and acceptance criteria.