Magnetic Particle Testing (MPI)

Magnetic Particle Testing (MPI)

TTIS Ventures Pvt. Ltd. performs Dry Powder, Wet Visible and Wet Fluorescent Magnetic Particle testing inspection services to find surface/near-surface defects in ferromagnetic material.

Our certified technicians can perform these tests on-site as well in our lab. In magnetic particle testing, technicians magnetize the test piece made of ferromagnetic material and apply fine iron powder coated with a dye pigment to it. The particles cluster around discontinuities in the test piece allowing for visual detection under proper lighting conditions.

This technique requires a skilled technician to distinguish between relevant and irrelevant indications. Our well trained and experienced experts can perform every step of the process, including pre-cleaning and surface preparation, magnetic field introduction, media application, and interpretation of the resulting indications as well as post cleaning of the test piece and de-magnetization if necessary.

Types of Magnetic Particle Testing are:

  • Dry Powder Magnetic Particle Testing

  • Wet Visible Magnetic Particle Testing

  • Wet Fluorescent Magnetic Particle Testing (WFMPI)

Liquid Penetrant Inspection

Liquid penetrant inspection or dye penetrant testing is based on the properties capillary action on the surface of materials where liquids to rise when confined to a small opening or channels. A liquid with dye in it is applied to the test surfaces and the excess then wiped off. The surface it then analyzed for surface discontinuities or anomalies. TTIS Ventures Private Limited perform penetrant testing for a variety of industries for components with a wide range of shapes, sizes, and materials, including Metals, Composites , Glass, Ceramics, Rubber and Plastics.

TTIS Ventures Private Limited uses multiples forms of penetrant inspections to find defects in rolled products, castings, forgings, and welds:

  • Visible Liquid Penetrant Testing.

  • Fluorescent Liquid Penetrant Testing.

  • Solvent Removal Liquid Penetrant Testing

  • Water washable Liquid Penetrant Testing

Our certified inspection technicians take into consideration all variables while selecting the penetrant method based on sensitivity levels, job and site conditions.

TTIS Ventures Private Limited uses penetrant testing to inspect:

  • Rolled Products: Anomalies such as cracks, seams, or laminations

  • Castings: Cold shuts, hot tears, porosity, blow holes, or shrinkage

  • Forgings: Cracks, laps, or external bursts

  • Welds: Cracks, porosity, undercut, overlap, lack of fusion, or lack of penetration

Penetrant Testing Inspection Benefits

The main advantages of penetrant testing include:

  • Relatively easy to perform

  • Highly-sensitive to small discontinuities

  • Applications for a wide range of materials

  • Large areas or large volumes of parts/material can be inspected rapidly and at low cost

  • Parts with complex geometries can be inspected with ease

Holiday Testing

At TTIS Ventures Private Limited we provide holiday testing which is a non-destructive test method applied on protective coatings to detect unacceptable discontinuities such as pinholes and voids. Holiday testing involves checking an electric circuit to see if current flows to complete the circuit. This testing is used to find coating film discontinuities that are not readily visible.

A holiday test is usually performed on tank interiors, chemical storage vessels and buried structures because of the importance of maintaining adequate coating protection in aggressive service environments. A holiday test is also known as a continuity test.

A holiday test is performed with a holiday detector, which is an electrical device used to determine the location of a gap or void in the coating. There are various techniques and tools available for holiday detection. Coatings applied to concrete substrates can also be tested for discontinuities using either a low-voltage or a high-voltage holiday detector, depending on the coating thickness.
A low-voltage holiday test is used when the coating system is less than 500 microns (20 mils) thick. A high-voltage holiday test is used when the coating system is thicker.

Ferrite content Analysis

Ferrite content analysis is a fast, inexpensive, and accurate way to measure delta ferrite content in austenitic and duplex stainless steels. Proper ferrite content provides a balance between ductility, toughness, corrosion resistance and crack prevention. Heat, pressure and caustic environments require materials and welds with very high metallurgical integrity. A correct ferrite measurement can help to avoid both solidification cracking and corrosion in stainless steel welds, pipes, plates, pressure vessels and petrochemical components. The delta ferrite percentage or number allows a technical assessment of material corrosion susceptibility, mechanical properties, service suitability, and service reliability.

To perform properly ferrite testing, both a minimum material thickness and a minimum specimen size are required. Test results are interpreted in accordance with current specifications and/or customer requirements.

TTIS Ventures Private Limited performs Ferrite Testing to

  1. Austenitic stainless steel/Duplex stainless steels

  2. Welds (tubing, etc.)

  3. Normal construction steel with Austenitic chrome alloy steel welded cladding (Ex. Boilers, vessels, etc.)

  4. Weldments, Castings, Forgings, Weld Overlays, Wrought materials

  5. Weld materials

  6. Butt/fillet welds

  7. Category A-D welds

  8. Stainless weld overlays on non-ferrous interfaces

  9. In-service and in-construction components

Advantages

  1. Rapid and accurate analysis

  2. Highly portable digital technology

  3. Variable calibration in both Ferrite Number (FN) and % Ferrite (FN) using AWS Standards

  4. Testing instrument meets all requirements of ANSI/AWS A4.2 and DIN EN ISO 8249

  5. Calibration is traceable to internationally approved IIW secondary calibration standards

Limitations

  1. Not recommended where the material is at temperatures greater than approximately 125 °F

  2. Surface preparation is very important for test accuracy

  3. Both a minimum material thickness and size are required

  4. Shape of the test piece may have a negative effect on the results obtained. Correction calculations can be performed in some instances.

Surface Roughness

Surface Roughness is a measurement of vertical deviations on the surface of a sample in its ideal form. Depending on the size of these deviations the surface will either be rough or smooth. A very rough surface will interact differently with other materials and usually wear more quickly due to the coefficient of friction. This may be undesirable when a contact between two parts must be smooth. However, manufacturing a very fine surface is more costly. The application of the parts and their interactions to surface condition will ultimately determine the desired surface roughness. Roughness is often a good predictor of the performance of a mechanical component, since irregularities on the surface may form nucleation sites for cracks or corrosion. On the other hand, roughness may promote adhesion.
At TTIS Ventures Private Limited we use a tool known as a profilometer to measure the deviations in surface texture. A diamond-tipped stylus runs over the surface of the material reacting with variations in surface texture. When a variation is measured high or low, the profilometer reports the variant data. After scanning, the surface will be given a rating in roughness per the specification requested.