FIELD OF THE INVENTION
The invention relates to a reference block for phased array ultrasonic testing of
MIAB (Magnetically Impelled Arc Butt) welded tube butt joint. More particularly,
the invention relates to a device for measuring efficiency of an ultrasonic testing
equipment and probe combination.
BACKGROUND OF THE INVENTION
Ultrasonic testing is a well-established non-destructive testing method for
evaluating the quality of raw material and welded products like tube to tube butt
welded components. MIAB is a solid phase welding process where an arc is
struck between the two tubes being joined and the arc is rotated all round the
circumference. After sufficient heating has been done on the surface two tubes
are butted against each other and an upsetting force is applied. This expels the
liquid and semi solid metal along with oxides that had been produced by the heat
of the arc thereby the fresh oxide free surfaces are brought into contact against
each other and pressure applied. This allows two tubes to join together. The
probable defects expected in MIAB weld are the lack of bonding between the

two tube inclusive of oxides and foreign materials. In the case of UT, the lack of
fusion generally takes place in a vertical plane which is very difficult to detect.
Additionally, the high axial mechanical force brings the two surfaces into very
close contact that leads to a situation where ultrasound signal does not get
reflected from the areas of defect due to lack of bonding.
US5837880 discloses an ultrasonic calibration block which performs all the
functions of an IIW block, but not representing the defects if existing in the job.
US5163027 describes a calibration block to generate a look-up table of standard
waveform amplitudes.
JP2007057414 describes an ultrasonic calibration block with ceramic embedded
welded sample to act as reference block in respect of defects on (ceramic
rectangular body).

US2009282895 describes a mechanical device holding the probes to achieve
optimal alignment on the sensors with a specimen. By determining the
mechanical tolerance-induced offset between the beam direction of the
ultrasound transducers and the ideal beam directions, the defects are detected.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a device for measuring
efficiency of an ultrasonic testing equipment and probe combination, which
further acts as means for setting the amplifier gain used as a reference reflector.
Another object of the invention is to propose a device for measuring efficiency of
an ultrasonic testing equipment and probe combination, which formed of
material which is identical to that of the job.
A still another object of the invention is to propose a device for measuring
efficiency of an ultrasonic testing equipment and probe combination, which is
configured with a reflector with surface similar to the actual defect.

Yet another object of the invention is to propose a device for measuring
efficiency of an ultrasonic testing equipment and probe combination, in which
the specific size of the surface of the natural defect is used as a reference.
A further object of the invention is to propose a device for measuring efficiency
of an ultrasonic testing equipment and probe combination, in which the natural
defect of specific size at a specified bonding region, is used as the reference .
A still further object of the invention is to propose a device for measuring
efficiency of an ultrasonic testing equipment and probe combination, which
identifies natural defects.
These and other objects are 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 for measuring efficiency of an ultrasonic
testing equipment and probe combination, comprising: a single block having a
projected face, with equivalent weld defect, at the interface between two
materials bonded, with the block being produced by a material identical to the
material of the job-piece is comprised of and with required size of the reflector.
The surface of the block constitutes a true representative of the job. The
material of the device is required to have the same heat treatment, geometrical,
metallurgical and acoustic properties as that of the job under test.

The present invention relates to a device for setting amplifier gain and sensitivity
of ultrasonic testing equipment.
The present invention incorporates a flat bottom hole and a side drilled hole to
represent natural defects.
According to the invention, a reference for Phased array ultrasonic testing is set
in a device consisting of two tubes joined together by MIAB welding process with
a plurality of holes in the form of flat bottom hole ranging between 0.8 to 1.50
mm in axial direction to simulate lack of bonding of different size. A plurality of
side holes with corresponding hole sizes is configured in radial direction
representing inclusion/pore of different size drilled in the weld region.
The device ensures that the surface of the reflector is similar to the actual
defect, and that the area of the reflector is equal to area of natural defect used
as reference. According to the invention a natural defect of specific size is used
as reference at a specified bonding region.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows an embodiment of the device according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The device comprises a single block produced by welding of a first tube (A) and
a second tube (B) with a fusion face (3) using material identical to that of the job
material used for MIAB welding. The first tube (A) having at least one each flat
bottom hole (1) and side drilled hole (2). The device has the same heat
treatment, geometrical, metallurgical and acoustic properties as that of the job
under test.
The UT probe (not shown) is initially set on the top surface of the first tube (A)
of the device and the UT probe (not shown) is moved forward and backward till
an echo from the reference reflector (1) i.e. flat bottom hole size 1.0 is
maximized. Then the gain control is adjusted to bring the echo height to 40%.
The amplifier gain setting is used as a reference for further testing of the job.

WE CLAIM:
1. A device for setting the calibration sensitivity level of an ultrasonic testing
equipment and probe combination, comprising :
- a first tube welded with a second tube with a fusion face to form a single
block;
- the first tube comprises at least one flat bottom hole acting as a
reference reflector, and at least one side hole, the ultrasonic testing probe
initially disposed on the surface of the first tube and moved backward and
forward till an echo from the reference reflector is maximized, the gain control
being subsequently adjusted to bring the echo height to 40%, characterized in
that the device is configured with identical material including associated
mechanical properties that of the job under test.

A device for setting the calibration sensitivity level of an ultrasonic testing
equipment and probe combination, comprising :a first tube welded with a second
tube with a fusion face to form a single block; the first tube comprises at least
one flat bottom hole acting as a reference reflector, and at least one side hole,
the ultrasonic testing probe initially disposed on the surface of the first tube and
moved backward and forward till an echo from the reference reflector is
maximized, the gain control being subsequently adjusted to bring the echo
height to 40%, characterized in that the device is configured with identical
material including associated mechanical properties that of the job under test