Intergranular Corrosion (IGC) Testing Services

Discover the world of intergranular corrosion (IGC) testing services and how important it is to protect the integrity of materials.

Talk to an Expert

TRUSTED BY

Precision-driven testing for dimensional accuracy and compliance

Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation
Results and Deliverables

Overview

Testing for intergranular corrosion (IGC) assesses the susceptibility of metallic materials, especially nickel-based alloys and stainless steels, to corrosion at grain boundaries. This type of corrosion occurs when the grain boundary regions differ chemically from the bulk material, usually due to carbide precipitation, sensitisation, incorrect heat treatment, or welding.

IGC can significantly impair structural integrity and mechanical strength without causing noticeable surface damage. Therefore, in sectors including oil and gas, chemical processing, power generation, and aerospace, standardised IGC testing is crucial for quality assurance, material certification, weld assessment, and failure analysis. Manufacturers can avoid early failures and ensure long-term material performance with IGC testing services, which provide standardised, trustworthy assessments using globally accepted techniques.

Scope, Applications, and Benefits

Scope

IGC testing defines methods to determine the susceptibility of stainless steels and corrosion-resistant alloys to grain boundary attack under controlled chemical environments. Standards such as ASTM A262 (for austenitic stainless steels), ASTM A923 (for duplex stainless steels), and ASTM G28 (for nickel alloys) provide procedures to assess sensitization and intergranular attack through chemical exposure and metallographic examination.

Applications

Material qualification for corrosion-resistant alloys
Weld procedure qualification and heat treatment validation
Quality control of stainless steel components
Failure analysis of corroded parts
Verification of solution annealing effectiveness
Assessment of sensitization after fabrication

Benefits

Detect susceptibility to intergranular attack
Ensure compliance with ASTM and industry specifications
Validate proper heat treatment and welding procedures
Prevent unexpected material failure in corrosive environments
Support certification and regulatory requirements
Enhance the reliability of critical components

Test Process

Specimen Preparation & Exposure

Machine, polish, clean, and immerse specimens per ASTM under controlled conditions.

Mechanical or Weight Loss Evaluation

Perform bend tests (where applicable) to detect grain boundary cracking or measure mass loss to determine corrosion rate.

Metallographic Examination

Prepare cross-sections and examine under an optical microscope to assess intergranular attack depth and morphology.

Interpretation & Reporting

Classify the material as acceptable or susceptible based on the relevant standard acceptance criteria and issue a detailed report.

Technical Specifications

Parameter	Details
Material Types	Austenitic SS, Duplex SS, Nickel Alloys
Test Environment	Specific acid solutions per standard requirement
Temperature Range	Typically, boiling conditions depending on the method
Exposure Duration	15 minutes to 120 hours (depending on practice)
Evaluation Method	Microscopic examination, bend test, or weight loss measurement

Instrumentation Used for Testing

Boiling test apparatus with temperature control
Acid-resistant test vessels and condensers
Precision analytical balance for weight loss measurements
Metallographic sample preparation equipment (cutting, mounting, polishing)
Optical microscope for grain boundary evaluation
Digital imaging systems for documentation
Fume hood and chemical safety systems

Results and Deliverables

Pass/Fail Classification as per applicable ASTM standard
Degree of Intergranular Attack (IGA) measurement
Corrosion Rate (when applicable)
Microstructural images showing the grain boundary condition
Bend test observations (cracking or fissures)
Detailed test report including test method, exposure conditions, and compliance statement