TNT, pelletized

In TNT pellets the initial Type II low-order detonation does not lead immediately to the final high order but to an intermediate level, of almost normal rate but of very low shock luminosity. A luminous strip due to the collision of the shock waves of two low-ordet detonations in TNT is observed in the simple dark space in some still photographs. Initiation at slightly below the limit, in all of the expls studied, produces low-order detons that fade after traversing-a short distance and the wave fronts show a strong shock effect. In TNT pellets the intermediate-order may also fade... 

The first expl streamer developed for the Mark 29 device by the Eastern Laboratory (EL) of the duPont Co, Gibbstown, NJ was made with pressed TNT pellets or blocks. 

Finely-divided TNT, as obtained by fume condensation, is more sensitive to impact than the crystalline material (Ref 1) TNT which has been exposed to light is also more sensitive. TNT pellets pressed from flake TNT undergo substantial reductions in rate of detonation and sensitivity to initiation after storage for one week at 65° (Ref 2). These changes are accompanied by exudation of oily impurities, and recrystn and sementation of the TNT... 

Its rate of detonation, as detd by the Dautriche method, was about the same as that of TNT (6880m/sec). Its sensitivity to impact, as detd in Fr, was considerably lower than for PA, but according to tests conducted in Engl, TNPht was more sensitive than PA (Ref 8). When pellets of TNPht (d 0.25g/cc) were fired in a manometric bomb, the pressure developed was 2490kg/sq cm, as against 3230 for PA... 

The first and still successful dense slurry was sensitised with TNT and therefore consisted of a suspension of TNT and solid ammonium nitrate in a solution of ammonium and sodium nitrates gelled with cross-linked guar gum. The TNT is preferably in the form of small pellets. No further fuel than the TNT is essential but aluminium can be added for increased... 

Tetryl (C7H5N508) is a pale yellow crystalline solid. It is moderately sensitive to initiation by friction and percussion and is used in the form of pressed pellets as primers for explosive compositions that are less sensitive to initiation. It is slightly more sensitive than picric acid and considerably more sensitive than TNT. In the early 1900s, tetryl was used as base charges for blasting caps but now has been replaced by PETN and RDX. During World War II, tetryl was used as a component of explosive mixtures. 

Note PA primers were used in each test. A specially constructed device was used for measuring vels of molten samples, such as at temps of 173 183°all the above expls, except PA. Extremely high vel for TNN at 183° was due to decompn of chge prior to initiation McGarry Stevens (Ref 2) detd by drum camera method the rates of deton of Tetryl, RDX Comp A-3 (all in pelleted form) 50/50 Pentolite, TNT Comp B (all cast) and hand-tamped Comp C-4. The rates of these sticks 1-1/8 inch in diam by 18 inches long were measured after exposure to initial low, ambient and high temps. It was found that the deton rates of these expls,... 

Bomb Burster, AN-M13., designed for use (in conjunction with igniter AN-M9) in incendiary bomb AN-M47A4, consists of a plastic tube 0.45-inches in diam, 36.0-in long, provided at each end with a soft brass cup. It is filled with ca 65 g of TNT and has a Tetryl pellet at each end (Ref 51a, P 5-15)... 

Ho 301 40-mm HE Ammo for use in Ho-301 40-mm AC Cannon had proj filled with TNT, contg in forward part a pellet of PA. The proplnt chge (0.4oz) consisted of small greenish-gray, square flakes (ca 1mm in size) enclosed in a silk bag (pp 296—97)... 

KH-Charge (KH-Ladung in Ger). The designation for a compressed charge consisting of 4-8 pellets of TNT, wrapped in paper and glued on the inside with an acid-free glue such as dextrin... 

The hose couplings, buoyancy control (air pressure) and method of initiation (by Prima-cord) were the same as for the NOL Streamer in Use at that time. The only apparent weakness of the duPont streamer was that the pellets were broken to some extent by handling and countermining. The disadvantage of foe pellet load was largely eliminated by the EL development of a blend of flaked and grained TNT for use in the NOL canvas sock... 

The Fulminate detonated the Tetryl pellets from which the. detong wave passed thru the TNT crystals to the cast TNT and so on, with increasing velocity to the main charge of Amatol (Ref 1, pp 162—63)... 

CA 66, 87228q(1967) (High-d, pelleted expls suitable for wet boreholes were prepd from 38—73% AN, 25—60% insol HE sensitizer, and 1—3.5% hydrocarbon binder and waterproofing agent. For example AN 68, TNT 30 paraffin wax 2% were mixed and exttuded under high pressure to give 0.25"inch diam pellets, d 1.4, which detonated at 3500m/sec when packed into 4-inch diam pipe)... 

R.J. Anderson J.F. Short, Canp 799408(1968) CA 70, 79652r (1969) [Water-resistant pelletized blasting compns comprising prills of TNT coated with an oxidant component in a binder are described. The oxidant was a 1 1 mixt of NaNC>3 AN and comprised 50—75%.by wt of the compns- the binder was a mixt of Ca lignosulfonate and polyethylene oxide) and comprised 2—10% of the compns. If desited, up to 20% metallic fuel could be included. The final pellets had a diam of 0.25—0.625 in. and a d 1.60g/cc. 

In the test described in Ref 2, the pellets were made of TNT instead of PA (Picric Acid) of original test (Ref 1), because TNT is less sensitive and more uniform. They were not phlegmatized with oil, as only a limited quantity can be incorporated with.the expl, the excess being driven aut again on pressing. Most of the reported experiments were carridd out with TNT incorporated with 4 to 14% paraffin wax pressed at 400 kg/cm2 to pellets of 25mm... 

ADT and ADV Propoll ants are described in confidential "Propellant Manual, SPIA/M2, Johns Hopkins Univ, Silver Spring, Maryland(1959)> Unit Nos 394 395 Advance Detonation. In 1941, Woodhead (Ref 1) observed that the velocity of detonation of unconfined columns of pressed tetryl pellets was higher by several hundreds m/sec when there was a continuous cylindrical cavity in the column. Later (Ref 2), the same investigator observed that this phenomenon takes place with HE S more sensitive than TNT (such as gelignite, mixt tetryl/TNT, etc) but is not observed with straight TNT. He also discovered that... 

C.G. Dunkle of Pic Arsn conducted studies of the rate of deton of TNT and, amatols at a d of 1.5 in Shelby steel tubing of 1ID and initiated by pressed tetryl pellets. His data (Ref 70) indicated, by extrapolation, that the rate of deton of AN, under the experimental conditions given, should be 3700 m/sec. The amatols uniformly detond under the conditions mentioned, but the 50/50 amatol consistently failed to deton when extruded,lead tubing was substituted for steel tubing... 

---