Corrosion testing & evaluation

TWI has dedicated laboratories for electrochemical and direct exposure small scale tests, larger facilities for testing specimens under load in sweet conditions, seawater (including CP), plus laboratories for H 2S sour service testing. Evaluation of materials corrosion behaviour is undertaken by relevant techniques covering rapid electrochemical testing and longer term direct exposure tests in simulated environments. Testing is in accordance with internationally recognised standards or developed by our experts in conjunction with client requirements as part of our corrosion services. Testing capabilities include:

Hydrogen cracking

  • Electrochemical evaluation of materials and coatings

  • Salt spray ranking assessment

  • Testing of materials under load and with cathodic protection in seawater including corrosion fatigue.

  • Weld corrosion testing to assess weld metal, HAZ and parent material with 12-channel electrochemical weld tester for monitoring up to 12 different weldments in parallel. Monitoring of the individual weldment regions over extended periods by AC & DC test methods, plus laboratory cells and low flow conditions.

  • Sour and Sweet service testing for the oil & gas sector at ambient pressure or at elevated pressure and temperature in autoclaves (200 bar and 200°C) with constant and variable loads (corrosion fatigue, SSRT and ripple loading all in H 2S/CO 2 etc).

  • Hydrogen autoclave for the study of hydrogen disbondment of weld overlays and cladding, materials embrittlement and hydrogen attack for the petrochemical, chemicals and power generation sectors.

Standard test methods are also employed for routine assessments in accordance with the recognised standards for sensitisation, CPT, CCT etc. Testing of components may also involve electrochemical studies and long-term testing in purpose designed configurations.

TWI undertakes all studies according to strict confidentiality and can test materials using recognised standards (ISO, ASTM, NACE etc) or specifically designed procedures using the following techniques:

Creep testing rigs
  • Testing under load
    • Testing configurations include: tensile, 4-point bent beam, U-bend, smooth or pre-notched geometries etc as appropriate
    • Constant load (dead-weight) ambient and elevated pressure testing
    • Slow strain rate testing (SSRT)
    • Ripple load testing
    • Corrosion fatigue (including tests in H 2S)
  • Simulated service environments
    • Sour service
    • Sweet service testing
    • Brines
    • Seawater (natural or artificial)
    • Hydrogen atmosphere at pressure
  • Electrochemical testing
    • 12-Channel ACM Weld Tester for preferential weldment corrosion
    • Crevice-free cells (Flushed port/Avesta Cells)
    • Purpose designed test cells including multiple sample test environments
    • DC and AC techniques for metals and coatings
    • Critical Pitting Temperature, (CPT) and Critical Crevice Temperature, (CCT), testing
    • Long-term exposure testing with LPR, galvanic current, potential monitoring and AC Impedance measurement
 Electrochemical testing laboratory

Analytical facilities

A full range of analytical equipment is available to assess samples and specimens including SEM with EDX, EPMA, X-ray diffraction and OES, Hydrogen analysis, FT-IR with ATR, DSC etc for material chemical analysis of metals, welds and plastics.

To discuss your specific needs contact our Corrosion Team.

Corrosion Services Copyright © 2003 TWI Ltd

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