Civil Engineering Reference
In-Depth Information
4.3 Comparison Between the Different EEC
Determination Approaches
Since the EEC determination methods are essentially the inverse of the other (i.e.,
one is based off the difference in mechanical power and the other is based off the
difference in temperature), the resulting EEC profiles should be equivalent. The
EEC profiles are calculated using both methods and then compared to each other
in the next section.
4.3.1 SS304 Electroplastic Effect Coefficient Profiles
In this section, EEC profiles derived from the previously described mechanical and
thermal methods will be presented, and the effects of different die speeds will also
be examined. Table
4.3
shows the different tests required to generate the EEC pro-
files using both of the methods. In particular, there was a batch of conventional com-
pression, and an EAF compression tests for each respective current density and die
speed combination. In addition, there was a stationary electrical test batch run for
each respective current density. All tests are described in the table. Figures
4.18
and
4.19
display mechanical and thermal EEC profiles for tests run at 12.7 and 25.4 mm/
min with starting current densities of 15 and 25 A/mm
2
. Because two different die
speeds are analyzed in each figure (and the tests are different time lengths), the
x
-axis was chosen to represent the percentage of the compressive stroke completed
rather than time, to allow for ease of comparison between all four tests.
In Fig.
4.18
, a starting current density of 15 A/mm
2
is explored. Please note
that the
x
-axis on this figure and the following figure is in terms of “% Stroke
Completed.” This is due to the fact that there are two different deformation speeds,
and by using this unit for the
x
-axis, the EEC profiles for both speeds can be com-
pared. From the figure, both methods of determining the EEC are extremely accu-
rate with respect to each other, for both die speeds. The EEC profile for the slower
Table 4.3
Deformed and stationary electrical
tests for determining EEC profiles for SS304 [
1
,
7
]
Deformed/Stationary
Current density (A/mm
2
)
Conv./EAF
Die speed (mm/
min)
Conv.
-
12.7
Deformed
EAF
15
12.7
Deformed
Deformed
EAF
25
12.7
Conv.
-
25.4
Deformed
Deformed
EAF
15
25.4
Deformed
EAF
25
25.4
EAF
15
-
Stationary
Stationary
EAF
25
-
