This document discusses three types of ultrasonic scanning methods - A-scan, B-scan, and C-scan. A-scan displays the amplitude of received ultrasound signals as a function of time. B-scan produces a two-dimensional cross-sectional image by moving the transducer along an object. C-scan creates a planar two-dimensional image of internal structures without dismantling parts. Applications of these methods include thickness measurement, defect detection in welds, analyzing cracks in metals and welds, and locating flaws inside engine components.

1. A B C SCAN
DISPLAYS
NAME:MICHEAL BERDINANTH M
REG.NO:3122 22 5001 071
Date:18/02/2023 Sec:6
BRANCH:CSE
Engineering Physics
Subject code : UPH2176
Assignment –II

2. ULTRASONIC SCANNING METHODS
- A,B AND C SCAN DISPLAYS
In the Ultrasonic scanning methods, the principle,
construction and working is the same as
that of the Ultrasonic flaw detector. Here, it is based on the position of the transducer and the
output displayed in the CRO screen, we can classiy the scanning methods into three types:
A-scan
B-scan
C-scan
All these three modes of scanning are obtained with respect to the pulses of
Ultrasound transmitted into and received from the specimen.
The three modes are explained below.

3. A-Scan Presentation
*It displays the amount of received ultrasonic energy as a function of time.
*The relative amount of received energy is plotted along the vertical axis and the
elapsed time is displayed along the horizontal axis. The reflected sound waves
from the different reflectors have different amplitudes according to the nature of
the reflectors. Hence, the A-scan is called the amplitude-modulated scan.
Echo Amplitude Vs Time:
 Large initial pulse at interface.
 Small flaw echo(for flaws
smaller than sound beam).
 Large back reflection.
Applications:
• A-scan is primarily used for measuring the thickness of materials, detecting
defects in welds, and measuring distances.
• In medical applications, A-scans are used to assess ocular biometry for
intraocular lens calculation, corneal thickness measurement, and to detect
retinal detachment.

4.  A-scan gives engineers an efficient way to assess pipe flaws in underwater
pipelines.
 In addition to underwater applications, A-scan testing has proven useful in
making sure metallic pipes for drinking water transmission and other fluid
transmissions.

5. B-Scan Presentation
B-scan, also known as a Brightness scan, is a two-dimensional imaging technique
that displays the internal structures of an object in a cross-sectional view. B-scans
are created by moving the transducer along a linear path over the object being
scanned. The advantage of this type of presentation (B-Scan) is that both the
length of the flaw and its depth below the surface is revealed.
Applications:
 B-scan machine is to inspect
surfaces of metals where there
can be cavities or defects in
them.
 B-scan machines is used in
inspecting welds or cracks in
vessels which is under pressure,
such as a boiler.

6.  Other main application that uses these machines is inspections on aircraft
wings or fuselages.
These three applications (and many others) use B scan radiography due to its
ability to produce high-quality images at high speeds and with great accuracy,
making it superior to most other inspection methods.

7. C-Scan Presentation
C-scan, also known as a Color scan, is a two-dimensional imaging technique that
displays the internal structures of an object in a planar view. C-scan technology is
designed for examining industrial parts without having to dismantle them. In the
C-Scan front and back surface reflections are not used, instead, the reflection from
the flaw is the only one that is projected

8. Applications:
 The main application of a C-scan or XRD scan in an NDT process is to
analyze cracks that are not visible to the naked eye.
 It finds cracks on welds and can also locate them inside components such as
engine blocks, cylinder heads, valves, etc.
 In Nickel alloys, it finds the flaws like inclusions or porosity in castings made
by sand molds which are generally very difficult to detect with conventional
radiography techniques