The EN ISO 9934-1:2016 is an international standard that specifies the method for magnetic particle testing of ferromagnetic materials. This non-destructive testing technique is commonly used in various industries, such as manufacturing, aerospace, automotive, and oil and gas, to detect surface and subsurface defects in components and structures.
The Principles of EN ISO 9934-1:2016
This standard involves applying a magnetic field to the material being tested and then magnetic particles onto the surface. These particles will be attracted to areas with magnetic flux leakage caused by defects, making them visible to inspectors. The particles, which can be either dry or wet suspended in a liquid carrier, are applied either by spraying or by immersing the test object into the suspension.
Equipment and Procedure
To perform magnetic particle testing according to EN ISO 9934-1:2016, several pieces of equipment are required. This includes a magnetizing device, magnetic particles, and suitable lighting conditions. The inspection procedure involves four main steps:
Magnetization: A magnetic field is applied to the component either by using a permanent magnet, electromagnetic yoke, or special coils.
Particle Application: Magnetic particles are applied to the test object's surface while the magnetic field is maintained.
Inspection: Inspectors examine the surface for indications of defects, which appear as brightly colored accumulations of particles.
Demagnetization: After the inspection, the residual magnetic field is removed from the component to prevent any interference in subsequent operations.
The Benefits and Limitations
Magnetic particle testing offers several advantages. It is a relatively quick and cost-effective method to identify defects on the surface and just below the surface of ferromagnetic materials. It can detect both surface-breaking and subsurface defects, such as cracks, porosity, laps, seams, and inclusions. Additionally, it has high sensitivity and can be used on a wide range of shapes and sizes of test objects.
However, EN ISO 9934-1:2016 also has some limitations. It requires direct contact with the surface being tested, making it unsuitable for components with complex geometries or hard-to-reach areas. Magnetic particle testing can only be applied to ferromagnetic materials, excluding non-magnetic metals and non-metallic materials. Furthermore, the inspection results are qualitative and require skilled technicians for accurate interpretation.
Nina She