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No. 99MBB091A
14.5.22 Core roughness depth, Rk
(Depth of the roughness core profile)
14.5.23 Reduced peak height, Rpk
(Average height of the protruding peaks above the roughness core profile)
14.5.24 Reduced valley depth, Rvk
(Average depth of the profile valleys projecting through the roughness core profile)
14.5.25 Material portion, Mr1
14.5.26 Material portion, Mr2
14.5.27 Peak area, A1
14.5.28 Valley area, A2
Referring to the figure, a straight line is calculated for the central region of the material ratio
curve *1 which passes through two points (A and B) different in the material ratio by 40%
and having the smallest gradient. The core roughness depth Rk is the vertical distance
between the ordinate values (i.e. slice levels) of the straight line intersecting two lines at
mr[c] = 0% position (C) and mr[c] =100% position (D), respectively.
Parameters Rpk and Rvk are calculated as the height of the right-angle triangle (CHJ or
DEG) which is constructed to have the same area as the “peak area”(CHI) or “valley
area”(DEF), respectively. The right-angle triangle corresponding to the “peak area, A1” has
Mr1 as its base, and that corresponding to the “valley area, A2” has 100% - Mr2 as its base.
A2
A1
Rk
Rvk
Rpk
Rvk
Mr1 Mr2
I
J
C
H
A
B
E
D
G
F
40%
mr[c] (%)
Depth (m)
*1: The abscissa of the BAC represents mr[c] values; the ordinate represents slice levels (m).
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