Applications

Applications

Below you will find a general outline of the capabilities of some common nondestructive testing methods. This is intended as brief summary of each discipline's capabilities.

We have about 60 years of combined NDT experience at JWJ and with those years, we have seen and solved scores of difficult applications. If you have and questions about your application, please email sales@jwjndt.com or call us. This service is of no charge to you.

ULTRASONICS

Measures thickness, velocity, or detects internal defects and variations, such as cracks, lack of fusion, delaminations, lack of bond.

Applications include, wrought metals, welds, brazed joints, adhesive or bonded joints, non-metallic materials, in-service parts.

Advantages		Disadvantages

Most sensitive to cracks		Couplant required
Immediate results		Complex, or small parts may be difficult to check
Automation possible		Reference standards required
Permanent record capability		Trained operators for manual inspections
Portable		Special Probes
High penetration capability		Surface condition

RADIOGRAPHY

Measures or detects, internal defects and variations, porosity, inclusions, cracks, lack of fusion, corrosion, geometry variation, density changes, misassembled, and misaligned.

Advantages		Disadvantages

Permanent records		Radiation hazard
Portable		Expensive
Geometry variation do not effect direction of radiation beam		Trained operators needed
		Linear defect may be missed
		Depth of defect not indicated
		Access needed to at least two sides of the part

EDDY CURRENT

Measures or detects surface and subsurface cracks and seams, alloy content, heat treatment variations, wall and coating thickness, crack depth, conductivity, and permeability.

Advantages		Disadvantages

High speed		Conductive material only
Low cost		Shallow depth of penetration
Automation possible for symmetrical parts		Reference standards required
Permanent record capability
No couplant required
No probe contact required

LIQUID PENETRANT

Measures or detects defects open to the surface of parts such as cracks, porosity, seams, laps, through wall leaks.

Advantages		Disadvantages

Low cost		Defect must be open to the surface
Portable		Parts must be cleaned before and after testing
Indications may be further examined		Surface films, such as coatings, scale, and smeared metal visually may mask defects

MAGNETIC PARTICLE

Measures or detects surface and qualified subsurface defects, cracks, seams, porosity, inclusions, and very sensitive for locating small tight cracks.

Advantages		Disadvantages

Low cost		Ferromagnetic materials only
Portable		Alignment of magnetic field is critical
Subsurface defects		Demagnetization required after the test
		Surface coatings can mask defects
		Pre and post cleaning necessary
		Messy

INFRARED THERMOGRAPHY

Measures or detects, hot spots, heat transfer, temperature ranges, temperature monitoring, and electrical assemblies.

Advantages		Disadvantages

Permanent record or thermal picture		Expensive
Remote sensing		Reference standards required
Portable		Poor resolution on thick sections

last updated July 09, 2008