FIELD OF THE INVENTION
The present invention relates to a device to determine the critical characteristics
of an ultrasonic probe. In particular, the invention relates to a device to
determine skew angle, resolution, probe index, sensitivity and beam spread of an
angle beam probe. More particularly, the invention relates to a device to
determine the skew angle and probe angle of an angle beam probe
corresponding to the changes in skew angle and probe angle due to wear and
tear of the probe.
BACKGROUND OF THE INVENTION
Ultrasound testing is one of the non-destructive testing method for evaluating
the quality of welded components. The probability of detection of defect depends
on the perpendicularity between a sound beam from the probe and the reflecting
surface of the defect in the weldment. The wear and tear of the probe causes
change in the refracted angle of the sound beam including the skew angle. This
change in the refracted angle and skew angle negatively influence the accuracy
of detection of the defect. The new device can be used to find out the change in
probe angle and skew angle of the probe. By knowing the skew angle, the sound
beam can be directed to have a perpendicular incidence with the defects at
predefined orientation.

US 5837880 teaches an ultrasonic calibration block which although is capable to
perform all the functions of an IIW block, but not accurately representing an
expected defect in the job. However, this prior art fails to detect the defects
expected in a welded component.
US 6938457 discloses a calibration block to calibrate ultrasonic transducer
comprising a guide surface and an angle gauge supported relative to the guide
surface. It can be used to determine the skew angle of the probe. However, this
prior art does not allow to determine the actual probe angle, resolution, probe
index, beam spread.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a device to determine skew
angle of the probe to calculate an accurate swiveling angle for scanning of
welded components.
Another object of the invention is to propose a device to determine skew angle
of the probe which can be used to make inline scanning.

A still another object of the invention is to propose a device to determine actual
angle of the probe to estimate the defect detecting capability of the probe based
on the orientation of defect.
Yet another object of the invention is to propose a device to determine skew
angle of the probe which can also be used to check the resolution of an angle
beam probe.
A still further object of the invention is to propose a device to determine skew
angle of the probe to calculate an accurate a swiveling angle for scanning of
welded components which is capable to locate the depth of the defect accurately
by finding out the actual angle of the probe.
A still further object of the invention is to propose a device to determine skew
angle of the probe to calculate an accurate a swiveling angle for scanning of
welded components which defines the beam spread of the probe.

These and other objects and advantages of the invention will be apparent from
the ensuring description.
At the outset of the description, which follows, it is to be understood that the
ensuring description only illustrates a particular form of this invention. However,
such a particular form is only an exemplary embodiment and the teaching of the
invention is not intended to be taken restrictively.
SUMMARY OF THE INVENTION
Accordingly, there is provided a device to determine the skew angle and probe
angle of an angle beam probe corresponding to the changes in skew angle and
probe angle due to wear and tear of the probe. The skew angle is found using a
curvature slot which gives a substantially accurate reflection without interference
from corner reflections. Apart from the angle of the probe, other associated
critical characteristics of the probe for example, resolution, sensitivity, probe
index, beam spread can also be determined using this device. This device can be
used to characterize the probe by finding the critical parameters.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1 - shows an embodiment of the device according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
As shown in figure 1, the device comprises a single block having a curvature of
90 to 110 mm with a slot of 7.5 to 8.5 mm depth in the curvature. This curvature
can be used to determine the skew angle of the probe. The slot is used to give
good reflection without any corner reflection. By knowing the skew angle, the
swiveling angle can be fixed during weld scanning is such that the swiveling
angle is greater than the actual skew angle of the probe. The points 45, 60 and
70 degrees can be used to find out the angle of the probe. The points along with
minor divisions can be used to ensure the actual angle of the probe which
depends on the wear and tear of probe surface. The holes H1, H2 and H3 can be
used to find the resolution capability of the probe. The beam profile of the probe
can be drawn by using these holes H1, H2, H3) which is present at different
depths from the surface of the welded components.

WE CLAIM :
1. A device to determine the skew angle and probe angle of an angle beam
probe corresponding to the changes in skew angle and probe angle due to
wear and tear of the probe, comprising :
- a single block having a curvature between 90 to 100 mm with a slot
having a depth between 7.5 to 8.5 mm in the curvature, the slot allowing
fixing of the skew angle of the probe due to provision of a substantial
accurate reflection without any corner reflection;
- the skew angle determined allows a substantially accurate swiveling angle
of the probe during the weld scanning of the welding component;
- the actual angle of the probe subsequent to the wear and tear of the
probe along the points of 45, 60 and 70 degrees including the minor
deviations;

resolution capability of the probe is determined based on change in the
dimension of holes (H1, H2, H3) due to wear and tear; and
the beam profile of the probe is allowed to be determined by applying the
values of the holes which is present at different depths from the surface
of the welding components.

ABSTRACT

The invention relates to a device to determine the skew angle and probe angle
of an angle beam probe corresponding to the changes in skew angle and probe
angle due to wear and tear of the probe, comprising : a single block having a
curvature between 90 to 100 mm with a slot having a depth between 7.5 to 8.5
mm in the curvature, the slot allowing fixing of the skew angle of the probe due
to provision of a substantial accurate reflection without any corner reflection; the
skew angle determined allows a substantially accurate swiveling angle of the
probe during the weld scanning of the welding component; the actual angle of
the probe subsequent to the wear and tear of the probe along the points of 45,
60 and 70 degrees including the minor deviations; resolution capability of the
probe is determined based on change in the dimension of holes (H1, H2, H3) due
to wear and tear; and the beam profile of the probe is allowed to be determined
by applying the values of the holes which is present at different depths from the
surface of the welding components.