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Pressed Charges. The density of TNT in large billets or in ammunition varies
with the method of preparation. Compression without application of a vacuum to
remove the residual air gives the following densities.
Pressure Density
(psi) (g/ma)
3 000 1.35
5 000 1.40
10 000 1.45
15 000 1.52
20 000 1.55
50 000 1.60
Compaction with the residual air removed and the TNT preheated to 70°C gives
the following density.
Pressure
(Psi)
12000
Powder
Temperature
(“(3
70
., , .
Density
k/cmY
1.63-l-64
Cast Charges. The density of cast TNT depends on the procedures used to melt,
cast, and solidify it. Typical densities are as follows.
Melting”
Preparative Procedure
Castingb
Solidification
TNT
Density
k/cmS)
Open 100% liquid Ambient 1.56-1.59
Open 75% liquid Ambient 1.59-161
Vacuum 50-75% liquid Ambient 1.61-1.62
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‘In an open melt the TNT is melted in atmospheric conditions. In a vacuum melt, the molten TNT is
subjected to a vacuum (-20 mm Hg) for a few minutes.
bBecause of the -7% volume change associated with the liquid-to-solid transition, solid TNT is usually
added to the liquid TNT. The TNT, either as a liquid or as a mixture of liquid and solids, is cast at a
temperature within a degree or two of the melting point (80-82”(J).
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