What is ACFM Testing?

Alternating Current Field Measurement or ACFM is an electromagnetic inspection technique that introduces an alternating current into the surface of the component to detect surface-breaking cracks.

The presence of a crack disturbs the electromagnetic field and the return signal is instantaneously converted by advanced mathematical techniques, so that the operator is alerted to the presence of a defect. Immediate defect sizing and recording is a major benefit compared to alternative NDT methods.

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What are the responsibilities of an individual who is certified to ACFM Level 2?

An individual certified to ACFM Level 2 has demonstrated competence to perform NDT according to ACFM procedures. Within the scope of the competence defined on the certificate, Level 2 personnel may be authorised by the employer to:

  • Select the ACFM technique for the test method to be used
  • Define the limitations of application of the testing method
  • Translate NDT codes, standards, specifications and procedures into NDT instructions adapted to the actual working conditions
  • Set up and verify equipment settings
  • Perform and supervise tests
  • Interpret and evaluate results according to applicable standards, codes, specifications or procedures
  • Prepare ACFM written instructions
  • Carry out and supervise all tasks at or below level 2
  • Provide guidance for personnel at or below level 2
  • Report the results of ACFM test

ACFM Level 2 training at IEQS GROUP covers the following


80 hrs of ACFM Level II training covers the following:

General Theory

  • History of electromagnetic testing
  • Terms and definitions used in electromagnetic testing
  • General principles of the ACFM technique
  • Electrical Theory. Further principles of AC theory
  • Equipment – ACFM equipment design and construction

Sector Specific Theory

  • Introduction to the range of available ACFM techniques
  • Types of equipment: Equipment selection and preparation
  • The effect of the ACFM test on the material to be tested
  • Preparation for testing
  • Carrying out the test
  • Post-test procedures reporting
  • Codes, standards and specifications
  • Briefing of remote probe operator
  • Preparation for testing
  • Surface preparation
  • ACFM techniques
  • Safety precautions, fire hazards, electrical safety
  • Conduct of test
  • Test procedure
  • Factors affecting the sensitivity of the ACFM technique
  • Probe and instrument set-up
  • Computer file handling
  • Detectability of defects. General advantages and limitations of the test method with regard to defect detection.
  • Characterisation of defects. Difficulties and limitations
  • Interpretation and reporting
  • Types of discontinuity and their identification
  • Responsibilities for reporting
  • Welding product technology
  • How defects are formed