NITRO DERIVATIVES OF TOLUENE^321The sensitiveness of TNT to friction is also very low, but becomes higher when
TNT is in the molten state.
TNT gives a lead block test figure of 260-310 cm^3 , according to various authors,
which is 94-98% of that given by picric acid. In a mortar it gives a value 90%of that for picric acid and its sand test value is 95% of that for picric acid.
The rate of detonation of TNT, as reported by various authors, is given in
Table 76.
TABLE 76RATE OF DETONATION OF TNT (m/sec)Density of
loading
g/cm^20.25
0.56
0.83
1.10
1.21
1.34
1.40
1.45
1.50
1.52
1.60
1.62according
to Kast *[57]
5940
6400
6590
6680
according to
Friedrich** [116]2385
3100
4100- 4720
6990according to
Roth*** [117]- .-
-_
4720
5900
7400
according to
Cybulski****
[118]- 5250
6930
* For charges 21 mm in diameter. initiated by a 2 g detonator, in the open.
** In a metal pipe 10-15 mm in diameter.
*** Charges in bakelite pipes of 4.5-8.2 mm internal diameter.
**** In a steel pipe 31.7 mm in diameter.Values ranging from 6900 to 7000 m/sec are usually accepted as the maximum
rate of detonation of TNT.
Such outstanding advantages of TNT, its low sensitiveness to impact and friction,
safe handling, considerable safety in storage (because of the low reactivity of the
compound), relative safety in manufacture and relatively high explosive power,
have made TNT the most widely used of all high explosives since the beginning
of the twentieth century up to the present time.
As an explosive, TNT is used both compressed (in demolition charges) and
in the cast form in shells and also in demolition charges. In the latter case deto-
nators comprising compressed charges of TNT, tetryl, hexogen, or penthrite are
used.
For large calibre armour-piercing shells, the sensitiveness of TNT alone is too
high so it is usually diminished by adding a small quantity (1-2%) of desensitizing