ISO 9934 Non-Destructive Testing - Magnetic Particle Testing

The “ISO 9934 Non-destructive testing - Magnetic particle testing” standard, published by the International Organization for Standardization (ISO), consists of the following sub-sections published under the same title:

• The standard “ISO 9934-1 Part 1: General principles” describes the general principles for magnetic particle testing of ferromagnetic materials. Magnetic particle testing is primarily applicable for detecting discontinuities on the surface, especially cracks. It can also detect discontinuities just below the surface, but its sensitivity decreases rapidly with depth.

This standard specifies the surface preparation of the part to be tested, the magnetization techniques, the requirements and application of the testing medium, and the recording and interpretation of the results. Acceptance criteria are not defined. Additional requirements for magnetic particle testing of specific products are defined in the product standards.

The ISO 9934-1 standard plays a significant role in industries where structural integrity and safety are critical, including aerospace, automotive manufacturing, oil and gas, railways, shipbuilding, power generation, and heavy engineering.

Magnetic particle testing is a non-destructive testing technique used to detect discontinuities such as:

• Cracks
• seams
• Cold sources
• Overlays
• Lack of integration in the sources.
• Fatigue defects

This method works by magnetizing a ferromagnetic component and applying fine magnetic particles to its surface. When discontinuities interrupt the magnetic field, runaway fields are created. Magnetic particles accumulate around these runaway fields, forming visible signs of defects.

Magnetic particle testing is particularly effective because,

• It's fast
• It is relatively inexpensive.
• It is extremely susceptible to surface cracks.
• Suitable for complex geometries.
• Applicable during production or maintenance inspections.

However, it only works with ferromagnetic materials such as carbon steels, low-alloy steels, iron, and some nickel or cobalt alloys.

The ISO 9934-1 standard defines the general principles and requirements for conducting magnetic particle testing. This standard covers the following:

• Surface preparation requirements
• Magnetization techniques
• Selection and application of magnetic particles.
• Viewing conditions
• Evaluation and interpretation of indicators.
• Documentation and reporting
• Personnel qualifications
• Security requirements

This standard does not define acceptance criteria for defects. Instead, acceptance limits are determined by product standards, customer specifications, or industry codes. This standard also no longer applies to the magnetization method.

• The ISO 9934-2 Part 2: Detection Media standard describes the key properties of magnetic particle test products (including magnetic inks, powders, carrier liquids, and contrast-enhancing dyes) and methods for controlling these properties.

This standard is a significant international standard in the field of non-destructive testing. It focuses on the requirements and characteristics of sensing media used in magnetic particle testing.

Magnetic particle testing is commonly used to detect surface and near-surface discontinuities in ferromagnetic materials. The effectiveness of this testing method largely depends on the quality and performance of the sensing media used during the inspection.

The ISO 9934-2 standard specifies technical requirements for magnetic particles, carrier fluids, contrast aids, and performance testing to ensure reliable and repeatable inspection results.

In magnetic particle testing, a ferromagnetic component is magnetized to create a magnetic field. If a crack or discontinuity exists, magnetic flux leakage occurs in the defect area. Detection media are then applied to the surface. Magnetic particles gather around the leakage area, creating visible markers that inspectors can assess. The accuracy and reliability of the inspection largely depend on:

• Particle size
• Particle mobility
• Magnetic properties
• Visibility under audit conditions
• Stability of suspensions
• Compatibility with the surface being inspected

This standard provides standardized requirements for controlling these factors. This standard specifies the requirements for:

• Magnetic particles
• Carrier fluids
• Contrast dyes
• Fluorescent materials
• Testing and verification methods
• Performance characteristics of sensing environments

This standard applies to both dry magnetic particle systems and wet magnetic particle suspensions.

The ISO 9934-2 standard categorizes sensing media into several main types.

• Dry magnetic particles: Dry particles, in powder form, are applied directly to the test surface. Their properties are as follows:
  • Suitable for rough surfaces.
  • It is effective for field investigations.
  • It is generally used in large structures.
  • It can operate at high temperatures.
• Wet magnetic particle suspensions: Wet systems suspend magnetic particles in a liquid carrier. Carrier liquids may include:
  • Water-based suspensions
  • Oil-based suspensions
• Visible detection environments: Visible particles are examined under white light. These particles are typically black, red, and gray. Contrasting dyes are often used to improve visibility on dark surfaces.
• Fluorescent sensing media: Fluorescent particles contain pigments that glow under ultraviolet (UV-A) light. These systems offer the following:
  • Very high sensitivity
  • Improved visibility of subtle discontinuities.
  • Improved inspection reliability in critical applications.

• Portable or transportable equipment
• Fixed installations
• Specialized test systems consisting of a series of processing stations forming a pipeline, for the continuous testing of components.

This standard also describes magnetization, demagnetization, lighting, measurement, and monitoring equipment. It specifies the characteristics to be provided by the equipment supplier, the minimum requirements for the application, and the method of measuring specific parameters. Where applicable, measurement and calibration requirements and in-service checks are also specified.

This standard is an international standard specifying the equipment requirements for magnetic particle testing, one of the most commonly applied nondestructive testing methods for detecting surface and near-surface discontinuities in ferromagnetic materials.

Magnetic particle testing is widely used in industries such as aerospace, automotive manufacturing, oil and gas, power generation, railways, shipbuilding, and heavy engineering. The reliability of this inspection method depends not only on proper procedures and qualified personnel but also on the quality and performance of the inspection equipment.

In short, the ISO 9934-3 standard specifies the technical requirements for magnetic particle testing equipment to ensure consistent, safe, and effective inspections. Magnetic particle testing is used to detect cracks and discontinuities in ferromagnetic materials. This process includes:

• Magnetization of the particle to be tested
• Application of magnetic particles to the surface.
• Observation of particle accumulations originating from magnetic flux leakage fields.

Defects such as cracks interrupt the magnetic field and create leakage areas that attract magnetic particles, producing visible signs. The effectiveness of this method largely depends on the following:

• Sufficient magnetization
• Appropriate particle application
• Suitable lighting conditions
• Reliable equipment performance

The ISO 9934-3 standard focuses specifically on the equipment required to meet these conditions.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the ISO 9934 standard.