11-2 Issue 05, 01/01 Krautkramer DM4E / DM4 / DM4 DL
11.1 Application information
General information
The DM4 DL is easy to use and produces reliable and
reproducible measurement data when correctly ap-
plied and when certain conditions are taken into con-
sideration which influence the measurement accuracy.
This chapter describes some of the most common
factors of influence.
Foreign inclusions inside the material
If, during a series of measurements, the DM4 DL sud-
denly indicates a value which is considerably smaller
than the adjacent measuring point close by, then the
cause could be a flaw within the material (e.g. foreign
inclusion) from which the sound pulse is reflected in-
stead of being reflected from the backwall. If this is the
case, this zone should be checked by means of a uni-
versal ultrasonic instrument or another suitable NDT
method in order to determine the cause of the con-
spicuous measured value.
Appendix Application information
Surface quality
Parallel tool marks on the coupling surface can lead to
measuring errors with strong surface roughness. If the
acoustic separation layer of the probe is oriented verti-
cally toward the marks, this effect does not occur.
In some cases, wrong measured values are obtained
from too rough surfaces due to excessive couplant
which collects between the probe and the test surface.
Very rough surfaces can completely obstruct coupling
(no coupling check indication). In such cases, surface
machining is required.
11-2 Issue 05, 01/01 Krautkramer DM4E / DM4 / DM4 DL
11.1 Application information
General information
The DM4 DL is easy to use and produces reliable and
reproducible measurement data when correctly ap-
plied and when certain conditions are taken into con-
sideration which influence the measurement accuracy.
This chapter describes some of the most common
factors of influence.
Foreign inclusions inside the material
If, during a series of measurements, the DM4 DL sud-
denly indicates a value which is considerably smaller
than the adjacent measuring point close by, then the
cause could be a flaw within the material (e.g. foreign
inclusion) from which the sound pulse is reflected in-
stead of being reflected from the backwall. If this is the
case, this zone should be checked by means of a uni-
versal ultrasonic instrument or another suitable NDT
method in order to determine the cause of the con-
spicuous measured value.
Appendix Application information
Surface quality
Parallel tool marks on the coupling surface can lead to
measuring errors with strong surface roughness. If the
acoustic separation layer of the probe is oriented verti-
cally toward the marks, this effect does not occur.
In some cases, wrong measured values are obtained
from too rough surfaces due to excessive couplant
which collects between the probe and the test surface.
Very rough surfaces can completely obstruct coupling
(no coupling check indication). In such cases, surface
machining is required.
To Next Page
Loading...
