Magnetic Particles Testing (MT) Level I & II

Magnetic Particle Testing (MT) Level I & II Course

The Magnetic Particle Testing (MT) Level I & II Course is designed to provide training in one of the most common non-destructive testing (NDT) methods used to detect surface and near-surface discontinuities in ferromagnetic materials. Magnetic Particle Testing uses a magnetic field to reveal flaws such as cracks, seams, and laps in materials like steel and iron.

Course Objectives:

Level I:

• Understand the basic principles of Magnetic Particle Testing (MT).
• Learn to perform magnetic particle inspection by applying the magnetic field and particles.
• Develop the ability to identify and classify indications under supervision.
• Acquire practical knowledge of magnetic particle application, detecting surface and near-surface defects.

Level II:

• Gain advanced knowledge of magnetic field characteristics and particle application methods.
• Learn how to interpret and evaluate indications for defect type, size, and severity.
• Qualify to supervise Level I personnel and independently perform MT inspections, ensuring compliance with standards.
• Prepare detailed inspection reports based on MT results.

Key Components of the Course:

1- Introduction to Magnetic Particle Testing (MT)

• Principles of MT: Understanding how magnetic fields interact with ferromagnetic materials.
• The concept of flux leakage: When a magnetic field is applied to a material, surface and near-surface defects cause interruptions in the magnetic field, creating flux leakage that can be detected with magnetic particles.
• Advantages of MT over other NDT methods for detecting surface and near-surface flaws.

2- Materials Used in MT

• Ferromagnetic materials: Only materials that can be magnetized (such as iron, nickel, and cobalt) can be inspected using MT.
• Types of magnetic particles used in the test:
  • Dry particles: Used in dusty environments or for rough surfaces.
  • Wet particles: Suspended in a liquid, providing better coverage and sensitivity.
• Visible particles: Provide color contrast under white light.
• Fluorescent particles: Provide high contrast under UV (black) light.

3- Magnetic Field Generation and Application

• Methods of magnetization:
  • Direct magnetization: Current is passed directly through the part, creating a magnetic field.
  • Indirect magnetization: A magnetic field is induced by an external coil or yoke without current flowing through the part.
• How to apply the magnetic field:
  • Longitudinal magnetization: Magnetic field runs parallel to the long axis of the component.
  • Circular magnetization: Magnetic field encircles the component.
• Understanding field direction and strength for detecting different defect orientations.

4- Types of Defects Detected by MT

• Surface and near-surface defects detected by MT include:
  • Cracks: Fatigue, thermal, or stress cracks.
  • Seams: Longitudinal defects from metal rolling processes.
  • Laps: Folding of metal material during the manufacturing process.
  • Inclusions: Non-metallic materials trapped within the metal.
• Understanding the relationship between magnetic field orientation and defect detection: defects perpendicular to the magnetic field produce stronger flux leakage and are easier to detect.

5- MT Techniques and Process (Level I)

• Step-by-step process of MT inspection:
  1. Surface preparation: Ensure the surface is clean and free from debris to allow proper detection.
  2. Magnetic field application: Apply the magnetic field using an appropriate magnetization technique.
  3. Particle application: Apply magnetic particles either as a dry powder or in a liquid suspension.
  4. Inspect for indications: Under proper lighting, visually inspect for indications where particles accumulate around flux leakage areas.
  5. Demagnetization: After the inspection, remove the residual magnetic field from the material to avoid interference with future operations.

6- Interpretation and Evaluation of Indications (Level II)

• Evaluating indications:
  • Relevant indications: Indications caused by actual defects such as cracks or inclusions.
  • Non-relevant indications: Indications caused by geometry changes, edges, or other factors that do not represent defects.
  • False indications: Unintended indications due to excessive particle accumulation or improper cleaning.
• Indication classification:
  • Characterizing defects based on size, shape, and location.
  • Determining whether the defect is surface-breaking or subsurface.

7- Equipment Used in MT

• Magnetizing equipment:
  • Yokes: Portable magnetization devices used for small parts and localized testing.
  • Prods: Electrodes used to introduce a direct current for larger or more complex parts.
  • Coils: Used to generate a circular magnetic field around the part.
  • Benches: Fixed equipment used in high-production environments for magnetizing and inspecting larger components.
• Inspection tools: UV lights for fluorescent particles, light meters for ensuring proper inspection conditions, and gauss meters for measuring the magnetic field strength.

8- Standards and Codes for MT

• Key standards and codes for performing and evaluating Magnetic Particle Testing, including:
  • ASME Section V: Nondestructive testing standards for MT.
  • ASTM E1444: Standard practice for magnetic particle testing.
  • AWS D1.1: Structural welding code covering MT of welded joints.
  • ISO 9934: International standard for magnetic particle testing.
• Acceptance criteria: Understanding acceptable defect limits for different industries and components.

9- Advanced MT Techniques (Level II)

• Multi-directional magnetization: Using different magnetization directions to detect complex defects.
• Wet particle suspension: More advanced application techniques to ensure thorough coverage and detection.
• Continuous and residual methods: Continuous magnetization during particle application versus residual magnetization after removing the magnetic field.

10 – Reporting and Documentation (Level II)

• How to prepare detailed inspection reports documenting:
  • Test procedure: Method of magnetization, particle type, and magnetizing current.
  • Indications found: Location, size, and nature of detected defects.
  • Recommendations: Repairs or further investigation needed based on defect severity.

11- Practical Applications and Hands-on Training

• Hands-on practice: Performing MT inspections on various test components and materials.
• Proper use of magnetizing equipment, applying particles, and interpreting indications.
• Practical exams: Performing MT inspections following written procedures and interpreting defect indications.

Target Audience:

• NDT Technicians: Seeking to specialize in Magnetic Particle Testing for quality control and defect detection.
• Weld Inspectors: Inspecting welded joints for surface and subsurface defects.
• Quality Control Inspectors: Responsible for ensuring material integrity using MT.
• Engineers and Supervisors: Overseeing MT inspections and analyzing results in production or maintenance environments.

Certification:

• Level I Certification: Certified to perform MT inspections under supervision after completing training and practical exams.
• Level II Certification: Certified to independently conduct MT inspections, supervise Level I personnel, and prepare inspection reports after advanced training and practical exams.