ULTRASONIC TESTING METHOD OF WHEEL
[Technical Field]
1000 11
The present invention relates to an ultrasonic testing method of
detecting a flaw in a rim portion by transmitting ultrasonic waves from
an array probe to a flange-side rim face of a wheel. Particularly, the
present invention relates to an ultrasonic testing method that reduces
intensity of a shape echo of surface texture of the flange-side rim face so
as to distinguish a flaw echo.
[Background Art]
[00021
There has been known a conventional ultrasonic testing method
that transmits ultrasonic waves from an array probe having transduces
linearly arranged through a flange-side rim face of a wheel such as a
railway wheel so as to detect a flaw in a rim portion of the wheel (in the
rim portion, one of two side faces vertical to a shaft of the wheel, on which
a flange is formed, is referred to as a "flange-side rim face" in the present .
specification). In this method, ultrasonic testing is carried out with the
array probe opposite to the flange-side rim face while rotating the wheel
in the circumferential direction. Generally, when flaw detection is
carried out while rotating the wheel, an angle between the transducer
alignment direction (also referred to as a "longitudinal direction",
hereinafter) of the array probe and the radial direction of the wheel is set
to be 0" when viewed in the axial direction so as to secure a greater area
of a region where the ultrasonic waves enter the surface of the wheel (also
I referred to as a "incident region", hereinafter).
Unfortunately, in this ultrasonic testing, the array probe receives
an echo reflected from a shape having surface texture roughness of the
flange-side rim face, etc. (hereinafter referred to as a "shape echo of the
surface texture"); and therefore, if a flaw exists in the vicinity of the
flange-side rim face, and if intensity of the flaw echo of this flaw is equal
to or less than intensity of the shape echo of the surface texture, it is
difficult to detect this flaw. Hence, it has been desired to reduce the
intensity of the shape echo of the surface texture of the flange-side rim
face.
[00031
In the ultrasonic testing using the array probe, there has been
known a method that determines an incidence angle of ultrasonic waves
to an object to be detected so as to prevent shape echoes from a region
other than a flaw detection region from returning to the array probe (see
Patent Literature 1, for example). Unfortunately, this method cannot
reduce intensity of a shape echo returning from the surface texture of the
object to be detected opposite to the transducer face of the array probe.
[Citation List]
[Patent Literature]
[00041
[Patent Literature 11 JP2007-933 11A
[Summary of Invention]
[Technical Problem]
[00051
An object of the present invention, which has been made in order to
solve the problems according to the conventional art, is to provide an
ultrasonic testing method of detecting a flaw in a rim portion by
transmitting ultrasonic waves from an 'array probe to a flange-side rim
face of a wheel, and capable of reducing intensity of a shape echo of
surface texture of the flange-side rim face, thereby distinguishing a flaw
echo.
[Solution to Problem]
[0006]
In order to solve the aforementioned probleins, the present
inventors have conducted various enthusiastic studies, and as a result,
have obtained the following findings.
The surface texture of the flange-side rim face of the wheel includes
a number of fine cutting tooth traces caused by a cutting tool at the time
of machining the surface, and the cutting tooth traces are formed in a
circumferential shape around a shaft of the wheel. Because the angle
between the transducer alignment direction of the array probe and the
radial direction of the wheel (this angle is also referred to as a "probe
setting angle", hereinafter) is 0" when viewed in the axial direction, the
ultrasonic waves transmitted from the array probe in the radial direction
of the wheel are reflected on the cutting tooth traces vertically
intersecting the radial direction of the wheel, and return to the array
probe as the shape echo of the surface texture. Hence, it is difficult to
distinguish a flaw echo returning from the vicinity of the flange-side rim
face from a shape echo of the surface texture of the flange-side rim face
(the surface texture of the flange-side rim face is also referred to simply
as a "surface texture", hereinafter).
[00071
To address this difficulty, it has been studied whether or not it is
feasible to distinguish the flaw echo returning from the vicinity of the
flange-side rim face from the shape echo of the surface texture by tilting
the probe setting angle to a degree in which no shape echo of the cutting
tooth trace returns to the array probe, and a probe setting angle for
attaining such a distinction has been found.
[00081
The present invention has been accomplished based on the result of
the above studies by the present inventors. That is, in order to solve the.
aforementioned problems, the present invention provides an ultrasonic
testing method of detecting a flaw in a rim portion of a wheel by
transmitting ultrasonic waves from an array probe to a flange-side rim
face of the wheel, the ultrasonic testing method comprising: disposing a
transducer face of the array probe to face the flange-side rim face; setting
an angle between a transducer alignment direction of the array probe and
a radial direction of the wheel to be 20 to 60" when viewed in an axial
direction of the wheel; and detecting a flaw by the array probe in which
the angle is set.
[00091
According to the present invention, the angle between the
transducer alignment direction of the array probe and the radial direction
of the wheel when viewed in the axial direction of the wheel, that is, the
probe setting angle is set to be 20" or more, and thereby allowing the
shape echo of the surface texture of the flange-side rim face to hardly
return to the array probe. Accordingly, the intensity of the shape echo of
the surface texture is likely to become less than the intensity of the flaw
echo, so that the flaw echo from the vicinity of the flange-side rim face
can be more easily distinguished from the shape echo of the surface
texture.
Because of the probe setting angle of 60" or less, the area of the
incident region at the time of detecting a flaw while rotating the wheel
becomes 112 or more of that at the probe setting angle of 0°, and the area
of the incident region is not so much decreased.
Accordingly, by setting the probe setting angle to be 20 to 60°, it is
possible to carry out the flaw detection with reduced intensity of the
shape echo of the surface texture.
100 101
Some wheels may include ring grooves for soundproofing. The
ring groove is formed in the outward radial direction from an inner face of
the rim portion around its entire circumference.
In such a wheel, if the probe setting angle is 0°, the ultrasonic
waves transmitted in the inward radial direction of the wheel are
reflected on the ring groove vertically intersecting the radial direction of
the wheel, and likely to return to the array probe; and therefore, it is
difficult to distinguish the flaw echo returning from the vicinity of the
ring groove from the shape echo of the ring groove.
It was found that at the probe setting angle of 20 to 60°, the shape
echo of the ring groove hardly returns to the array probe, and thus the
intensity of the shape echo of the ring groove is likely to become less than
that of the flaw echo. Hence, it becomes easier to distinguish the flaw
echo returning from the vicinity of the ring groove from the shape echo of
the ring groove.
Accordingly, in order to detect a flaw existing in two different
regions in the vicinity of the surface texture and in the vicinity of the ring
groove, this flaw can be accurately detected with a single array probe by
simply setting the probe setting angle to be 20 to 60°, which reduces the
intensities of the shape echoes of the surface texture and of the ring
groove.
[oo 111
At the probe setting angle of 0°, a shape echo of a throat face
located between the surface of the flange portion and a wheel tread (face
of the rim portion to be in contact with a rail) is likely to return to the
array probe; and therefore, it is difficult to distinguish the flaw echo
returning from the vicinity of the throat face from the shape echo of the
throat face. To address this difficulty, it has been studied whether or not
it is feasible to distinguish the flaw echo returning from the vicinity of the
throat face from the shape echo of the throat face by tilting the probe
setting angle to a degree in which no shape echo of the throat face returns
to the array probe, and as a result, it was found that the probe setting
angle is preferably set to be 40 to' 60".
In the wheel having no ring groove, in order to detect a flaw
existing in two different regions in the vicinity of the flange-side rim face
and in the vicinity of the throat face, this flaw can be accurately detected
with a single array probe by simply setting the probe setting angle to be.
40 to 60°, which reduces the intensities of the shape echoes of the surface
texture of the flange-side rim face and of the throat face.
In the wheel having the ring groove, in order to detect a flaw
existing in three different regions in the vicinity of the flange-side rim
face, in the vicinity of the ring groove, and in the vicinity of the throat
face, this flaw can be accurately detected with a single array probe by
simply setting the probe setting angle to be 40 to 60°, which reduces the
intensities of the shape echoes of the surface texture of the flange-side
rim face, of the ring groove, and of the throat face, respectively.
[Advantageous Effect of Invention]
[oo 121
According to the present invention, in the ultrasonic testing method
of detecting a flaw in the rim portion by transmitting ultrasonic waves
from the array probe to the flange-side rim face of the wheel, it is possible
to reduce intensity of the shape echo of the surface texture of the flangeside
rim face, and thereby distinguishing the flaw echo.
[Brief Description of Drawings]
[OO 131
Figure 1 is a cross sectional drawing in a radial direction of a wheel
showing an example of the wheel to which an ultrasonic testing method
according to an embodiment of the present invention is applied.
Figures 2A and 2B are drawings explaining an example of an
ultrasonic testing apparatus used in the ultrasonic testing method; -
Figure 2A is a schematic drawing of the ultrasonic testing apparatus, and
Figure 2B is a schematic drawing of an array probe included in the
ultrasonic testing apparatus.
Figure 3 is a perspective view showing an arrangement position of
the array probe in a conventional ultrasonic testing method.
Figures 4A and 4B show a B-scope in flaw detection at a probe
setting angle of 0"; Figure 4A is a photograph of the B-scope, and Figure
4B is a schematic drawing of the B-scope.
Figures 5A and 5B are drawings showing propagation paths of
ultrasonic waves transmitted to a flange-side rim face; Figure 5A is a
cross sectional drawing in a radial direction of the propagation paths
when viewed in a circumferential direction of the wheel, and Figure 5B is
a plan view of the propagation paths when viewed in an axial direction of
the wheel.
Figure 6 is a perspective view showing an arrangement position of
the array probe in the ultrasonic testing method according to the
embodiment of the present invention.
Figure 7 is a plane view of the propagation paths of ultrasonic
waves when viewed in the axial direction of the wheel.
Figure 8 is a drawing showing comparison of each intensity of shape
echoes of a surface texture, of a ring groove, and of a throat face with
intensity of a flaw echo of an artificial flaw formed in a rim portion, using
various probe setting angles.
[Description of Embodiment]
[0014]
Hereinafter, an ultrasonic testing method according to an
embodiment of the present invention will be described with reference to
accompanying drawings. In the ultrasonic testing method according to
the present embodiment, a flaw in a rim portion is detected by
transmitting ultrasonic waves onto a flange-side rim face of a wheel.
Figure 1 is a cross sectional drawing in a radial direction of a wheel
showing an example of the wheel to which an ultrasonic testing method
according to the present embodiment is applied.
A wheel 1 is a railway wheel, and includes a boss 11 at its center,
and a rim portion 12 at the circumference of the wheel. The rim portion
12 includes a flange portion 13 projecting in the outer circumferential
direction and a wheel tread 14 to be in contact with a rail, both of which
extend around the entire outer circumference of the wheel. In the
- . - . .-
present specification, a portion located between the surface of the flange
portion 13 and the wheel tread 14 is referred to as a throat face 15. In
the rim portion 12, one of two side faces vertical to a shaft of the wheel 1,
on which the flange portion 13 is formed, is referred to as a flange-side
rim face 16.
LOO 151
The wheel 1 may include a ring groove 17 for soundproofing, and
may include no ring groove 17 in some cases, and Fig 1 shows the wheel 1
including the ring groove 17 as an example of the wheel 1. The ring
groove 17 is formed in the outward radial direction from the inner face of
the rim portion 12 around the entire circumference.
[0016]
Figures 2A and 2B are drawings explaining an example of an
ultrasonic testing apparatus used in the ultrasonic testing method
according to the present embodiment; Figure 2A is a schematic drawing
of the ultrasonic testing apparatus, and Figure 2B is a schematic drawing
of an array probe included in the ultrasonic testing apparatus.
The ultrasonic testing apparatus 2 includes the array probe 3
disposed to face the flange-side rim face 16 of the wheel 1. The
ultrasonic testing apparatus 2 also includes an array flaw detector 4
having a function of transmitting transmission-reception control signals
to the array probe 3 etc., and also amplifying signals received from the
array probe 3, a personal computer 5 having a function of setting various
parameters for the array flaw detector 4, and receiving signals from the
array flaw detector 4 so as to generate images such as an A-scope image
and a B-scope image, etc., and a control panel 7 for supplying rotation
signals and others to a rotary driving section 6 described below.
The ultrasonic testing apparatus 2 further includes the rotary
driving section 6 for supporting a bottom of the wheel 1 with its shaft
horizontal, and also rotating the wheel 1 for the purpose of detecting
flaws in the entire circumference of the rim portion 12, and a tank 8 for
soaking the wheel 1 and the array probe 3 in water. The array probe 3
includes multiple transducers 32 linearly arranged, and a face of the
array probe 3 where ultrasonic waves are transmitted from the
transducers 32 is referred to as a transducer face 31.
[OO 171
An example of the ultrasonic testing method using the
aforementioned ultrasonic testing apparatus 2 will be described,
hereinafter.
In order to carry out the ultrasonic testing, the transducer face 31
of the array probe 3 is disposed to face the flange-side rim face 16, and
the tank 8 is filled with water as a coupling medium so that the wheel 1.
and the array probe 3 are soaked in the water. Oil or the like may also
be used as the coupling medium. Flaw detecting conditions, such as
intensity of the ultrasonic waves transmitted from the array probe 3 and
scanning speed, etc., are set in the personal computer 5, and the flaw
detecting conditions are converted into the transmission-reception control
signals by the array flaw detector 4, and then transmitted to the array
probe 3. The array probe 3 transmits the ultrasonic waves through the
flange-side rim face 16 into the rim portion 12, and transmits signals
corresponding to echo signals received from the rim portion 12 to the
array flaw detector 4. The array flaw detector 4 amplifies the received
signals from the array probe 3, and then transmits the signals to the
personal computer 5, and the personal computer 5 displays images such
as an A-scope image and a B-scope image. The personal computer 5
transmits rotation signals to the rotary driving section 6 via the control
panel 7 so as to rotate the wheel 1. In this manner, the flaw detection in
the rim portion 12 is carried out in the circumferential direction.
[0018]
The transmission and reception of the ultrasonic waves from the
array probe 3 are carried out, for example, by linear scanning (in the
linear scanning, a certain number of the transducers 32 included in the
array probe 3 are defined as a single transmission unit, and in
transmission of the ultrasonic waves per transmission unit, the ultrasonic
wave from each transducer 32 is transmitted in parallel with each other,
or each transducer 32 transmits the ultrasonic wave at different timing
so as to concentrate the ultrasonic wave transmitted from each
transducer 32 at one point. In this state, the array probe 3 is controlled
by the transmission-reception control signals from the array flaw detector
4 such that the transmission unit sequentially shifts in the alignment
direction of the transducers 32, and thereby performing parallel scanning
with the ultrasonic waves); or by steering scanning (in the steering
scanning, a certain number of the transducers 32 included in the array
probe 3 are defined as a single transmission unit, and in transmission of
the ultrasonic waves per transmission unit, the ultrasonic wave from
each transducer 32 is transmitted in parallel with each other, or the
ultrasonic wave is transmitted from each transducer 32 at different
timing so as to concentrate the ultrasonic wave transmitted from each
transducer 32 at one point. In this state, the exit angle is varied, and
thereby performing the scanning).
[00191
The ultrasonic testing method according to the present invention
has a feature in the arrangement position of the array probe 3, and thus
the arrangement position of the array probe 3 will be described below.
Conventionally, in general, for the purpose of securing a greater area
where the incident region passes at the time of detecting a flaw while the
wheel is being rotated, the angle (probe setting angle) between the
transducer alignment direction (longitudinal direction) of the array probe
3 and the radial direction of the wheel is set to be 0" when viewed in the
axial direction.
Figure 3 is a perspective view showing an arrangement position of
the array probe in a conventional ultrasonic testing method.
Fig. 3 shows only a part of the wheel 1.
The incident region extends in the radial direction.
Figures 4A and 4B show a B-scope in flaw detection at a probe
setting angle of 0"; Figure 4A is a photograph of the B-scope, and Figure
4B is a schematic drawing of the B-scope. In both the figures, the lateral
axis represents the propagation time of the ultrasonic wave, and the
vertical axis represents the scanning position of the ultrasonic wave.
Specifically, the lateral axis indicates a depth position from the flangeside
rim face 16, and the vertical axis indicates a position in the radial
direction in the flange-side rim face 16. In Figure 4, the shape of the rim
portion is indicated by solid lines.
[00201
In the rim portion 12 imaged by this B-scope, such an artificial flaw
of a flat-bottomed hole of 1 mm cp is formed that vertically extends from a
rim face opposite to the flange-side rim face 16 toward the flange-side rim
face 16. A distance from the flange-side rim face 16 to a front end of the
artificial flaw is 50 mm, and an echo of the front end of the artificial flaw
(flaw echo) is detected by the B-scope.
In the B-scope, a surface echo of the flange-side rim face 16 appears
in the vicinity of the flange-side rim face 16. The shape echo of the
surface texture' appears in a region from the flange-side rim face 16 to a
portion deeper than the surface echo. If the front end of the artificial
flaw is formed in a region where this shape echo of the surface texture
appears, and if the intensity of the flaw echo of this artificial flaw is equal
to or less than the intensity of the shape echo of the surface texture, it is
difficult to detect this artificial flaw.
A shape echo of the ring groove 17 appears at a position of the ring
groove 17, and also at a position deeper than the ring groove 17, and a
shape echo of the throat face 15 appears in the vicinity of the throat face
15. If the artificial flaw is formed in regions where the shape echoes of
the ring groove 17 and of the throat face 15 appear, and if the intensity of
the flaw echo of this artificial flaw is equal to or less than each intensity
. ..
of the shape echoes of the ring groove 17 and of the throat face 15, it is
difficult to detect this artificial flaw.
[00211
Figures 5A and 5B are drawings showing propagation paths of
ultrasonic waves transmitted to the flange-side rim face 16; Figure 5A is
a cross sectional drawing in a radial direction of the propagation paths
when viewed in a circumferential direction of the wheel 1, and Figure 5B
is a plan view of the propagation paths when viewed in an axial direction
of the wheel 1.
Each propagation path viewed in the circumferential direction of
the wheel 1 will be described with reference to Figure 5A.
The surface texture of the flange-side rim face 16 of the wheel
includes a number of fine cutting tooth traces generated by a cutting tool
at the time of machining the surface, and the cutting tooth traces are
formed in a circumferential shape around the shaft of the wheel.
Ultrasonic waves U1 obliquely transmitted from the transducers 32
across the flange-side rim face 16 in the inward radial direction are
reflected in the inward radial direction if the flange-side rim face 16 is
flat. The flange-side rim face 16, however, has a number of fine rough
cutting tooth traces in the radial direction. Hence, part of the ultrasonic
waves is reflected on the flange-side rim face 16, and returns to the
transducers 32 when viewed in the circumferential direction of the wheel
1. Part of ultrasonic waves U2 that is obliquely transmitted from the
transducers 32 across the flange-side rim face 16 in the outward radial
direction is also reflected on the flange-side rim face 16, and returns to
the transducers 32 when viewed in the circumferential direction of the
wheel 1.
100221
Each propagation path viewed in the axial direction of the wheel 1
will be described with reference to Figure 5B. In Figure 5B, only several
cutting tool traces are shown as a matter of convenience.
Because of the probe setting angle of 0°, ultrasonic waves U3 from
the transducers 32 are vertically reflected on the cutting tool traces, and
return to the transducers 32. If the flange-side rim face 16 has a rough
surface in the circumferential direction, the ultrasonic waves are
dispersedly reflected on the flange-side rim face 16 in the circumferential
direction; but the flange-side rim face 16 includes the cutting tool traces
that make the surface smooth in the circumferential direction, which are
generated by the cutting tool at the time of machining the surface, and
thus many of the ultrasonic waves return to the transducers 32 when
viewed in the axial direction of the wheel 1.
[00231
As described above, part of the ultrasonic waves transmitted from
the array probe 3 returns to the array probe 3 when viewed in both the
circumferential direction and the axial direction of the wheel 1.
Consequently, part of the ultrasonic waves transmitted from the array
probe 3 is reflected on the surface texture, and returns to the array probe
3, which appears in the B scope as the shape echo of the surface texture.
Such a shape echo of the surface texture that returns to the array
probe 3 is not resulted from an echo of the ultrasonic waves transmitted
and received in the approximately vertical direction, but resulted from an
echo of the ultrasonic. waves obliquely transmitted and received across
the flange-side rim face 16 by the transducers 32, and thus this echo has
a longer propagation time than that of the surface echo of the flange-side
rim face 16 (the surface echo of the flange-side rim face 16 is formed by
ultrasonic waves transmitted and received in the approximately vertical
direction across the flange-side rim face 16). Hence, in the B-scope, the
shape echo of the surface texture appears even at a deeper position than
the surface echo of the flange-side rim face 16. Consequently, it is
difficult to detect a flaw existing at a position where the shape echo of the
surface texture appears in the B-scope.
lo0241
Because of the prqbe setting angle of 0°, ultrasonic waves U4 and
U5 from the transducers 32 are vertically reflected on the throat face 15
and on the ring groove 17, respectively, and return to the transducers 32.
Hence, the shape echoes of the throat face 15 and the ring groove 17
appear in the B scope. Consequently, it is difficult to detect a flaw
existing at positions where the shape echoes df the throat face 15 and of
the ring groove 17 appear in the B-scope.
[00251
In the present embodiment, the ultrasonic testing is carried out
using the probe setting angle of more than 0".
Figure 6 is a perspective view showing an arrangement position of
the array probe. Only part of the wheel 1 is shown. The incident region
is oblique relative to the radial direction. Figure 7 is a plane view of the
propagation paths of ultrasonic waves when viewed in the axial direction
of the wheel 1.
In the case of the probe setting angle of more than 0°, the
propagation path of the ultrasonic waves viewed in the circumferential
direction of the wheel 1 is the same as that at the probe setting angle of
0°, and as similar to the case described with reference to Figure 5A, part
of the ultrasonic waves transmitted from the transducers 32 in the
inward and outward radial directions is reflected on the flange-side rim
face 16, and returns to the transducers 32.
In the propagation path of the ultrasonic waves viewed in the axial
direction of the wheel 1, since the probe setting angle is more than 0" as
shown in Figure 7, ultrasonic waves U6 transmitted from the transducers
32 in the inward radial direction are reflected on the cutting tool traces,
and thereafter hardly return to the transducers 32. Ultrasonic waves
U7 transmitted from the transducers 32 in the outward radial direction
are reflected on the cutting tool traces, and thereafter hardly return to
the transducers 32, either.
Because of the probe setting angle of more than 0°, ultrasonic
waves U8 transmitted from the transducers 32 to the throat face 15 are
reflected on the throat face 15, and thereafter hardly return to the
transducers 32. Similarly, ultrasonic waves U9 transmitted from the
transducers 32 to the ring groove 17 are reflected on the ring groove 17,
and thereafter hardly return to the transducers 32.
[0026]
Figure 8 is a drawing showing comparison of each intensity of
shape echoes of a surface texture, of the ring groove 17, and of the throat
face 15 with intensity of a flaw echo of an artificial flaw formed in the rim
portion 12, using various probe setting angles.
Each of the array probes 3 that were used had 128 transducers, a
pitch between the adjacent transducers of l'mm, the simultaneous
excitation number of 24, and an array, probe length of 128 mm. The
array probes had four different widths of 7 mm, 9 mm, 11 mm, and 12.5
mm.
. As similar to the B scope shown in Figure 4, an artificial flaw of a
flat-bottomed hole of 1 mm cp vertically extending from the rim face
opposite to the flange-side rim face 16 toward the flange-side rim face 16
was formed such that a distance from the front end of the artificial flaw to
the flange-side rim face 16 was 50 mm.
Sensitivity of the transducers 32 was adjusted such that the
intensity of the flaw echo of the artificial flaw becomes the same at every
probe setting angle.
As shown in Figure 8, with respect to the surface texture of the
flange-side rim face 16, the ring groove 17, and the throat face 15, each
case of having the intensity of the shape echo sufficiently less than the
intensity of the flaw echo of the artificial flaw was indicated by a
reference character A; each case of having the intensity of the shape echo
less than the intensity of the flaw echo of the artificial flaw, in which
there was a small difference in intensity but the artificial flaw could be
distinguished, was indicated by a reference character B; and each case of
having the intensity of the shape echo equal to or more than the intensity
of the flaw echo of the artificial flaw was indicated by a reference
character C.
[00271
In order to reduce each intensity of the shape echoes of the surface
texture of the flange-side rim face 16, of the ring groove 17, and of the
throat face 15 to be less than the intensity of the flaw echo of the artificial
flaw, the probe setting angle may be set as follows. Although four types
of the array probes 3 having different widths were used, but all the array
probes 3 had the same result.
In order to reduce the intensity of the shape echo of the surface
texture to be less than the intensity of the flaw echo of the artificial flaw,
the probe setting angle is preferably 20 to 45", and more preferably 30 to
45".
In order to reduce the intensity of the shape echo of the ring groove
17 to be less than the intensity of the flaw echo of the artificial flaw, the
probe setting angle is preferably 20 to 45", and more preferably 30 to 45".
In order to reduce the intensity of the shape echo of the throat face
15 to be less than the intensity of the flaw echo of the artificial flaw, the
probe setting angle is preferably 40 to 45", and more preferably 45".
Although the result using the probe setting angle of more than 45"
is not shown in Figure 8, at the probe setting angle of more than 45" to
less than 90°, each intensity of the shape echoes of the surface texture,
the ring groove 17, and the throat face 15 was sufficiently less than the
intensity of the flaw echo of the artificial flaw.
As the probe setting angle becomes greater, the area where the
incident' region passes becomes smaller at the time of detecting a flaw
while the wheel is being rotated. Accordingly, the probe setting angle is
set to be 60" or less so as to secure the area where the incident region
passes to be 112 or more of the area using the probe setting angle of 0". :
If it is acceptable to have a smaller area where the incident region passes,
the probe setting angle may be 70" or less, or 80" or less.
[0029]
Accordingly, the probe setting angle is set to be 20 to 60" in order to
carry out the ultrasonic testing with the reduced intensity of the shape
echo of the surface texture of the flange-aide rim face 16. More
preferably, the probe setting angle is set to be 30 to 60". Through this
configuration, the shape echo of the surface texture hardly returns to the
array probe. Accordingly, the intensity of the shape echo of the surface
texture becomes less than that of the flaw echo of the artificial flaw,
which makes it easier to distinguish the flaw echo returning from the
vicinity of the flange-side rim face 16 from the shape echo of the surface
texture.
[OO~O]
In the case of the wheel 1 having the ring groove 17, the probe
setting angle is set to be 20 to 60". Preferably, the probe setting angle is
set to be 30 to 60". Through this configuration, the intensity of the
shape echo of the ring groove 17 becomes less than that of the flaw echo
from the artificial flaw. Hence, it becomes easier to distinguish the flaw
echo returning from the vicinity of the ring groove 17 from the shape echo
of the ring groove 17.
Accordingly, in detecting a flaw existing in two different regions in
the vicinity of the surface texture and in the vicinity of the ring groove 17,
this flaw can be accurately detected with a single array probe by simply
setting the probe setting angle to be 20 to 60?, which reduces the
intensities of the shape echoes of the surface texture and of the ring
groove 17.
[003 11
In order to carry out the ultrasonic testing with the reduced
intensity of the shape echo of the throat face 15, the probe setting angle is
set to be to 40 to 60". More preferably, the probe setting angle is set to
be 45 to 60". Through this configuration, the intensity of the shape echo
of the throat face 15 becomes less than that of the flaw echo from the
artificial flaw. Accordingly, it becomes easier to distinguish the flaw
echo returning from the vicinity of the throat face 15 from the shape echo
of the throat face 15.
Accordingly, in the wheel having no ring groove 17, in detecting a
flaw existing in two different regions in the vicinity of the flange-side rim
face 16 and in the vicinity of the throat face 15, this flaw can be
accurately detected with a single array probe by simply setting the probe
setting angle to be 40 to 60°, which reduces the intensities of the shape
echoes of the surface texture and of the throat face 15.
In the wheel having the ring groove 17, in detecting a flaw existing
in three different regions in the vicinity of the flange-side rim face 16, in
the vicinity of the ring groove 17, and in the vicinity of the throat face 15,
this flaw can be accurately detected with a single array probe by simply
setting the probe setting angle to be 40 to 60°, which reduces the
intensities of the shape echoes of the surface texture of the flange-side
rim face 16, of the ring groove 17, and of the throat face 15, respectively.
(00321
The present invention is not limited to the configuration of the
above embodiment, and various modifications can be made without
departing from the spirit and scope of the present invention.
[Reference Signs List]
LO0331
1 ... Wheel
16 ... Flange-side rim face
3 ... Array probe
31 ... Transducer face

We claim:
[Claim 1]
An ultrasonic testing method of detecting a flaw in a rim portion of
a wheel by transmitting ultrasonic waves from an array probe to a flangeside
rim face of the wheel, the ultrasonic testing method, comprising:
disposing a transducer face of the array probe to face the flangeside
rim face;
setting an angle between a transducer alignment direction of the
array probe and a radial direction of the wheel to be 20 to 60" when
viewed in an axial direction of the wheel; and
detecting a flaw' by the array probe in which the angle is set.
[Claim 2]
The ultrasonic testing method according to claim 1, wherein
the' angle is set to be 40 to 60".