General Information - NOVOTEST UD3701 Operation Manual

Operation manual
Ultrasonic Flaw Detector NOVOTEST UD3701
Correct and effective use of flaw detector requires obligatory availability:
 Technical characteristics of flaw detector comply with requirements of test tasks;
 Relevant quality-control procedures;
 Well-qualified operator.
Present OM gives operator only instructions about intended use of the device. It does not give
understanding about influencing factors while testing and basic principal of ultrasonic.
Ultrasonic
Operator must be familiar with basic principal of theory about propagation of ultrasonic waves,
including understanding of sound velocity, damping, echo and reflected signal, limitations and
boarders for sound beam, etc.
Study
Operator must complete relevant training courses for correct use of flaw detector, getting clear
understanding about general principal of ultrasonic testing and practical skills for testing the particular
kind of products.
Testing
For correct ultrasonic testing operator must have quality-control procedure for this particular
product and must know special requirements for ultrasonic testing: aims of testing, choice of
appropriative testing device (method of scanning), choice of the probe, determination of known testing
conditions in materials of such kind, choice of reflector with minimal surface, cutting-off level, etc.
Evaluation of defect area
There are two main methods of evaluation of defect area.
1. By defect boarders:
If the diameter of sound beam is less than defect area, then it can be used for determination of
defect boarders. The less is beam diameter, the more accuracy in determination of defect
boarders. And vice versa, when the beam is rather wide, then determined boarders could be
quit differ from real ones.
2. By amplitude of echo-signal:
If the beam radius is more than defect area, then defect area is evaluated by the next way:
maximal echo-signal amplitude of the defect is compared to maximal amplitude of artificial
reflector in a special test block. Usually, echo-signal amplitude of the real defect is less than
amplitude of artificial reflector with the same area. This is because of not the exact
perpendicular position of the real defect to the probe beam and irregular shape of defect
surface, and it should be taken into account when testing.
Quality-testing procedures
User must know and understand quality-testing procedures, which are worked out for relevant
products.
Thickness measurement
Thickness measurement by ultrasonic – is a result of mathematical multiplication of ultrasonic
velocity in material and impulse passing time. Flaw detector allows to get the precise time value for
ultrasonic waves. The correct velocity setting depends on operator.
Sound velocity
Accuracy for thickness measurement and for defect position evaluation basically depends on the
correct setting of ultrasonic velocity in the material. Velocity depends on material physical
characteristics and its temperature.
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GENERAL INFORMATION