Introduction To Ultrasonic Testing (UT)

Ultrasonic test instruments have been used in industrial applications for more than sixty years. Since the 1940s, the laws of physics that govern the propagation of high frequency sound waves through solid materials have been used to detect hidden cracks, voids, porosity, and other internal discontinuities in metals, composites, plastics, and ceramics, as well as to measure thickness and analyze material properties.

Conventional UT Basic Theory

Sound waves are simply organized mechanical vibrations traveling through a medium. These waves will travel through a given medium at a specific speed or velocity, in a predictable direction, and when they encounter a boundary with a different medium they will be reflected or transmitted according to simple rules.

3

0 2 4 6 8 10

crack echo

back surface echo

initial pulse

Oscilloscope, or flaw detector screen

plate

crack

Piezoelectric Transducer

Conventional UT Basic Theory

4

Conventional UT Probe Configuration

With a conventional UT probe, a single piezoelectric element converts an electrical signal into a mechanical vibration.

Source: NDT Resource Center

(www.ndt-ed.org)

Phased Array Ultrasonic Testing (PAUT)

What we see in Medical Ultrasonic Test

What is the Difference in Medical Ultrasonogram and Phased Array Ultrasonic Test?

Nothing Special, Both are Phased Array Ultrasonic Test

Medical Industrial

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Phased Array Probe Configuration

• Essentially, a phased-array probe is a long conventional probe

cut into many small elements, which are individually excited.

Phased Array Probe Configuration

• It is like having many small conventional UT probes integrated inside a single probe.

…

128 elements !

How Does Phased Array Work?

Angle beam covers from angle 40o to 70o with 1o angle increment.

Phased Array Angle Coverage

30˚

Olympus OmniScan SX Phased Array Equipment

A-Scan, S-Scan and C-Scan

A-Scan

S-Scan

C-Scan

S-Scan

C-Scan

A-Scan

Weld Overlay System

Full weld overlay system that enables to visualize the relative position of indications in relation to the weld geometry. Easily Configure the Weld Geometry in the equipment. Such as type of weld joint, weld preparation angle, bevel height, bevel width, root gap, root face, thickness of the specimen etc.

Defect Positioning

Defect Positioning

Image sizing cursors available for X2 – X1 and/or Y2 – Y1 indication sizing

•Defect can be accurately sized•X-direction i.e. defect length•Y-direction i.e. defect depth

Defect Sizing

Phased Array C-Scan:Report with complete information

Immediate report from the equipment can be transferable through pen drive.

Phased Array Ultrasonic Test Application

Ship Welding Power Plant Gas Pipe Weld

Gas Field Pipe Line Weld Power Plant Boiler Tube

Phased Array Ultrasonic Test Application

Steel Structure Weld Small Boiler Weld Inspection

Comparison of RT and PAUT

Radiography – Practical Problems 1. Radiation safety 2. Licensing 3. Disruption to work area 4. Chemical wastes 5. Large volumes of film 6. Film storage and deterioration 7. Subjective interpretation 8. Relatively slow inspection 9. RT cannot size in vertical plane 10.RT poor at detecting planar

defects.

PAUT vs. RT

1. Phased Array Ultrasonic Testing (PAUT) potentially offers solutions to ECA

2. Capability of vertical sizing 3. Better detection of critical planar defects 4. Inspections tailored to weld profile and

defects 5. Generally PAUT has better detection than

RT, especially for cracks 6. Many trials performed globally7. Overall results support PAUT as better

quality inspections.

Economics of PAUT vs. RT

1. Higher licensing costs for RT 2. Major headaches in shipping and storing

isotopes 3. Higher cost in waste disposal, storage etc.4. Cheaper PAUT Inspection Cost5. No film cost in PAUT6. No chemical cost in PAUT7. No production interruption in PAUT.

Root Crack

Radiography

Phased Array Image

Sample Comparison of RT vs. PAUT

Porosity

Radiography

Phased Array Image

Sample Comparison of RT vs. PAUT

Inclusion

Radiography

Phased Array Image

Sample Comparison of RT vs. PAUT

Lack of Root Fusion

Radiography

Phased Array Image

Sample Comparison of RT vs. PAUT

Concave of Root

Radiography

Phased Array Image

Sample Comparison of RT vs. PAUT

PAUT vs. RT Advantages

PAUT vs. RT Advantages

1. Many functional advantages from switching from RT to PAUT.

2. No radiation 3. No licensing 4. No chemical wastes 5. Less subjective data interpretation 6. Minimizes data storage problems 7. Minimizes materials handling issues 8. Minimizes production disruptions 9. Better detection of planar defects 10.Can size in vertical plane for ECA 11.Lower reject rates 12.Fast and cost effective

PAUT Code Updates

Codes

1. ASME Code Case N- 659-2 permits Phased Array Ultrasonic Testing (PAUT) for Replacement of RT with PAUT for feeder tubes in nuclear reactor.

2. ASME CC 2541 Permits Phased Array Ultrasonic Testing (PAUT) in Section V, Article 4.

3. ASME CC 2235-9 permits UT in lieu of RT in Section VIII, Divisions 1 and 2.

4. ASME CC 2557 permits PAUT S-Scan in Section V, Article 4.

5. ASTM has published three Standard Practices: 2491, 2700, 2904

6. ISO, Chinese, Japanese working on PAUT codes.