Ultrasonic flaw detector Beijing TIME High Technology TUD360

Sampling frequency reach up to 160MHz
Color TFT LCD display
Memory up to 1024 A scanned images, parameters and 64000 thickness values
32 detecting channels are available with separated detecting parameters and DAC curve in every channel
Equipped with gate setting and alarming function
Two scanning modes: A scan and B scan
Auto gain and manual B scanning
USB 1.1,fullspeed communication port available
Can be connected with PC to print out result
Pulser voltage adjustable

Accessories

Normal beam, Angle beam, dual crystal and immersion –  focused & non focused probes.

Sub-miniature, miniature, normal and large crystal sizes.

Wide range of frequencies.

Can be custom made.

Wide range of standard calibration blocks as:

ASTM, ASME, BS, DIN, AWS, IS.

Made of steel and aluminum.

Each block with serial number and test certificate.

Can be custom made.

Small pocket size.

Metric-English conversion.

Auto calibration.

Wide range of probes.

Big LCD display.

Microprocessor based.

DIGISCAN DS-322

• Touch Weather protected industrial housing
• Easy to use direct access to all function
• Small compact size, light weight
• Colour TFT display with excellent visibility
• Fast update rate
• High speed digitiser
• Parabolic DAC curves
• Reference echo pattern at background
• Echo fill/unfill option for better visibility
• Through coating thickness measurement
• Auto / Selectable PRF
• Surface mount micro component technology
• Direct interface to printer
• EECOWIN software for PC connectivity
• Affordable

NDT Career Development Tips

The success of any Nondestructive testing (NDT) methods and procedures depends upon the knowledge, skill, and experience of the NDT personnel involved in the profession. The person(s) responsible for detection, interpretation and evaluation of indications, such as Ultrasonic testing, Radiographic testing, or Magnetic particle testing, must be qualified and certified to specific industry or other acceptable government or industry standards such as American Society for Non destructive Testing (ASNT) Personnel Qualification and Certification as per SNT-TC-1A or Indian Society for Nondestructive testing (ISNT) for different levels like Level I (1), II (2), III (3) or any other Internationally recognized personnel qualification training and certification. The person should be familiar with the respective NDT inspection test method/s, know the potential types of discontinuities peculiar to the material, and be familiar with their effect on the structural integrity of the part.

Inspection personnel should know where discontinuities occur or can be expected to exist and what effect they can have on the service life of the component or assembly. Misinterpretation and/or improper evaluation of discontinuities or improper performance of inspection tests can result in serviceable parts being rejected and defective parts being accepted. NDT personnel should be familiar with the detection of discontinuities such as: corrosion, inherent discontinuities, primary processing discontinuities, secondary processing or finishing, in-service discontinuities and codes, standards, specifications pertaining to the NDT.

It is with the interest in learning the skills and practicing, one can become a more professional NDT inspector/technician. More than just having the knowledge got in the training courses, it is important to learn the things with patience during NDT inspection and regularly practice the inspection/test methods to understand and develop the skills independently for a successful NDT career.

by Ravi Kumar T

Snells Law, Refraction and Reflection

Like light, when an incident ultrasonic wave encounters an interface to an adjacent material of a different velocity, at an angle other than normal to the surface, then both reflected and refracted waves are produced.

Understanding refraction and how ultrasonic energy is refracted is especially important when using angle probes or the immersion technique. It is also the foundation formula behind the calculations used to determine a materials first and second critical angles.

First Critical Angle

Before the angle of incidence reaches the first critical angle, both longitudinal and shear waves exist in the part being inspected. The first critical angle is said to have been reached when the longitudinal wave no longer exists within the part, that is, when the longitudinal wave is refracted to greater or equal than 90°, leaving only a shear wave remaining in the part.

Second Critical Angle

The second critical angle occurs when the angle of incidence is at such an angle that the remaing shear wave within the part is refracted out of the part. At this angle, when the refracted shear wave is at 90° a surface wave is created on the part surface

Formula

The relationship between the angle of the incident and refracted sound waves is descibed by the following formula:

Sin(A1)/V1 = Sin(A2)/V2

Where

A1 = The incident sound wave angle in degrees
V1 = The acoustic velocity of the incident material in metres per second
A2 = The refracted sound wave angle in degrees
V2 = The acoustic velocity of the refracted material in metres per second

By simple arrangment the formula may be changed to find any one of the values, provided that the other three unknown values are supplied.

E.g. To find the refracted angle, given the incident angle and velocity and the refracted material velocity the equation is rearranged as below:

V2 * (Sin(A1)/V1) = Sin(A2)

Getting the inverse of the answer, that is the inverse of Sin(A2) will return the angle in degrees of the refracted angle.

by Michael K Penn

Ultrasonic Test Equipment

The ultrasonic test equipment is used to provide information on the uniformity of concrete, cavities, cracks and defects. The ultrasonic test equipment is based on the pulse velocity method. It is recommended to measure the distance (path length) between the transducers as accurately as possible before the testing. The standard measuring procedure is:

* Apply the couplant. It is very important to ensure adequate acoustic coupling of the transducers to the surface under test. A thin layer of couplant should be applied to the transducers and the test surface. In some cases it may be necessary to prepare the surface by smoothing it.

* Position the transducers. Three transducer arrangements are commonly used:

1. The direct arrangement

2. Semi-direct arrangement

3. Indirect or surface arrangement

* Wherever possible it is recommended to use the direct arrangement as this ensures the maximum signal transmission between the transducers. The semi-direct arrangement is less sensitive than the direct, but more sensitive than the indirect arrangement. The path length is the distance between the centers of each transducer. The indirect method is particularly useful for determining crack depth, surface quality or in the case when only one surface is accessible.

* Perform the measurement

* Save the result

For compound measurements and uniformity testing a test grid should be drawn on the surface. Rebars affect the ultrasonic measurements as the signal will travel faster through the rebar than through the concrete. The location of rebars should be determined and ultrasonic tests should be positioned so as to avoid them. The British Standard 1881 Part 203 gives information on the effect of rebars on the expected results.

by Carla Fijnvandraat