T
1
=
Nmm
u
=
β
m
=
grade
z
1
=
Σ =
δ
1
=
K
A
=
K
v
=
K
Hα
=
K
Hβ
=
Z
E
=
MPa
1/2
Z
H
=
Z
ε
=
Ψ
d
=
σ
HP
=
MPa
m
eH
=
mm