Waygate Technologies Krautkramer USM 100, Operating Manual, Page: 192 / 330

5 Operation AWS D1.1 / AWS D1.5
192 Rev. 9 (09/2023) Krautkrämer USM 100
5.23 AWS D1.1 / AWS D1.5
You can evaluate defects in welds according to the
specifications AWS D1.1 and AWS D1.5.
After selecting AWS D1.1 or AWS D1.5 in the function
Eval Mode in (see page 159) the function group Evalu-
ation provides you with all the functions needed.
The rating of defects in welds according to the specifica-
tion AWS D1.1 is based on an evaluation of the signal
amplitude. In this method, the echo amplitude of the flaw
echo is compared with the echo amplitude of a known
reference reflector. In addition, the sound attenuation in
the test object is also taken into account.
The result is a dB value which is called flaw class. The
flaw class D is calculated according to the formula:
D = A – B – C
with:
● A = flaw gain (in dB)
Absolute instrument gain with which the maximum
flaw echo is at 50 % (±5 %) echo height.
● B = reference gain (in dB)
Absolute instrument gain with which the maximum
reference echo (e.g. the 1.5 mm side-drilled hole
from the reference standard K1 or IIW type 1 or 2) is
at 50 % (±5 %) echo height.
● C = sound attenuation factor (in dB)
The value is calculated according to the formula:
C = 0.079 dB/mm • (s – 25.4 mm), with s = sound
path of the flaw echo. The sound attenuation correc-
tion is calculated and displayed automatically by the
instrument. The value is set to zero for sound paths
smaller than or equal to 25.4 mm (1 inch).
● D = flaw class (in dB)
This is the result of the evaluation according to AWS.
The calculation is made in the instrument according
to the above-mentioned formula.