Logic NDT Solutions Ltd offers three major professional oilfield services, they include:
Magnetic Particle Inspection
Magnetic Particle Inspection is an investigative inspection technique used for finding surface/near surface defects in ferromagnetic material.
Magnetic Particle testing is a versatile inspection method used for field and shop applications.
How it Works
Magnetic particle testing works by magnetizing a ferromagnetic specimen using a magnet or special magnetizing equipment. If the specimen has a discontinuity, the magnetic field flowing through the specimen is interrupted, and leakage field occurs.
The specialist applies finely milled iron particles coated with a dye pigment to the specimen. These are attracted to leakage fields and cluster to form an indication directly over the discontinuity. The indication is detected visually under proper lighting conditions.
Basic Procedures for Performing Magnetic Particle Testing
The basic procedure that is followed to perform magnetic particle testing consists of the following:
- Pre-cleaning of component
- Introduction of Magnetic field
- Application of magnetic media
- Interpretation of magnetic particle indications
It is essential for the particles to have an unimpeded path for migration to both strong and weak leakage fields.Therefore, the component in question should be clean and dry before beginning the inspection process. The presence of oil, grease or scale may compromise the inspection.
The introduction of the magnetic field is done in some ways including the use of a permanent magnet, passing electrical current through the specimen or a coil of wire around the part or through a central conductor running near the part.
Types of Magnetic Fields Used For Magnetic Particle Inspection
Establishing two types of magnetic fields within the specimen is possible. These are a longitudinal magnetic field that runs parallel to the long axis of the part or a circular magnetic field that runs circumferentially around the perimeter.
Longitudinal Magnetic Fields
Longitudinal magnetic fields are produced using a magnetic coil or a permanent magnet called a magnetic particle yoke.
Circular Magnetic Fields
We produce Circular magnetic fields by passing current through the part or by placing the part in a strong circular magnetic field.
Magnetic particle inspection can use either wet or dry magnetic media.
Although The dry method is more portable, the wet method is generally more sensitive since the liquid carrier gives the magnetic particles additional mobility.
The Importance of a Skilled Inspector In The Process Of Magnetic Particle Inspection
A skilled inspector must interpret indications formed after applying the magnetic field. This requires the individual to distinguish between relevant and irrelevant indications.
- Can detect both surface and near-subsurface indications.
- Can inspect parts with irregular shapes easily.
- Pre-cleaning is not as critical as for some other inspection methods.
- A fast method of inspection and indications are visible directly on the specimen surface.
- Considered low cost compared to other NDT techniques.
- Very portable inspection.
Liquid Penetrant Inspection
This is an inspection technique based on the properties of capillary action, or the phenomenon of a liquid rising or climbing when confined to a small opening due to surface wetting properties of the liquid.
We use Penetrant testing to find surface breaking discontinuities on relatively smooth, nonporous surfaces.
Basic Procedures for Liquid Penetrant Inspection
The basic procedure necessary for carrying out Liquid Penetrant Inspection consist of the following:
Rolled Products: Penetrant identifies anomalies. (cracks, seams or laminations)
Castings: cold shuts, hot tears, porosity, blow holes or shrinkage, Forgings: Illuminating cracks, laps or external bursts.
Welds: To identify cracks, porosity, undercut, overlap, lack of fusion or lack of penetration.
Rotary Shouldered Threaded Drilling Tools: To identify cracks, corrosion pitting, mechanical damages on outside diameters, or inside diameters, and internal/external washing from fluid erosion.
Two Types of Liquid Penetrant Inspection
There are two main types of Penetrant, Fluorescent or Visible. Within each method, there are several methods including water washable, postemulsifiable-lipophilic, solvent removal and postemulsifiable-hyperdrophilic.
There are six main steps involved with penetrant testing:
- Application of Penetrant Material.
- Dwell Time/Penetrant Removal.
- Developer Application
- Post Clean.
Advantages of Liquid Penetrant Inspection
The main advantages of Penetrant Testing are:
- Relatively easy to use
- Used on a wide range of material types
- Large areas or large volumes of parts/material can be inspected rapidly and at low cost
- Easily inspect Parts with complex geometries
- Indications are produced directly on the surface of the part providing a visual image of the anomaly
- Using Aerosol spray cans make equipment very portable
A partial list of these certifications/techniques includes American Petroleum Institute (API), SNT-TC-1A, and DS-1 (TH Hill) Standards.
This is a visual inspection technique to multiple industries.
All NDT techniques are based on interpreting visual anomalies to determine test specimen soundness as detailed by the code or specifications to which the test is performed.
However, specific industries require a variety of visual inspection certifications to inspect their specific equipment.
A partial list of these certifications/techniques includes; American Petroleum Institute (API), SNT-TC-1A, ASNT, CGSB, and DS-1 (TH Hill) Standards.