Casting of explosives

Centrifugal Casting of Explosive Charges for HEAT Shell , PATR 2381 (1956) 5) M.J. 

Fluoroscopy is the visual examination of X-ray shadow images by means of a fluorescent screen. It may be used for the inspection of light mcCul CuStings soi s sinmiifiition castings of explosives etc. In this method, the images are formed directly on a screen and no films are required, which makes the cost of inspection lower than with ordinary X-ray examination Refs 1) Hackh s (1944), 349... 

The manufacturing process for the casting of explosive compositions nowadays uses carefully controlled cooling, vibration and vacuum tech-... 

Casting processes are needed especially in rocketry for the shaping of large propellant grains. Unlike in the casting of explosives, processes which cause shrinking and yield friable crystals cannot be applied. There are two solutions to this problem ... 

Novel catalyst compositions comprising complexes of tin(IV) salts and primary amine compounds allow delay of gelation until they dissociate under certain reaction conditions. Encapsulated catalysts have been used for delayed reaction in production of explosives this delay permits casting of explosives. 

The manufacturing process for the casting of explosive compositions nowadays uses carefully controlled cooUng, vibration and vacuum techniques to produce a homogenous, solid composition. The purity and size of the explosive crystals are carefully monitored and the complete product is subjected to X-ray analysis for the detection of cracks. 

N. Maropis, Ultrasonic Enhancement of Explosives Melt-Casting in Shaped-Charge Warheads , RR 70-32, Technidyne Incorporated, West Chester, Pa (1 70) 23) L. Friedel, G. 

Molten TNT has little or no solvent action on Explosive D, and consequently, cast Picratol consists essentially of a physical mixt of crystals of the two expls. Its d is 1.61 to 1.63g/cc, and this permits a wt of charge almost equal to that of Explosive D pressed under 10,000 to 12,000 psi. Picratol has the solubility and reactivity chracteristics of its ingredients. It is hygroscopic to the extent of only 0.02% when exposed to an atm of 90% RH at 30°... 

A detonation wave is a very rapid wave of chemical reaction which, once it is initiated, travels at a stable supersonic speed, called the detonation velocity, in a high explosive. Typically, detonation velocities for pressed or cast high explosives range from... 

Minimum impact energies to initiate the explosion of various exothermic mixtures, used for the continuous casting of steel, were determined. Components used included sodium nitrate, aluminium-iron scale, silicocalcium, ferrosilicon fluorspar, borax, etc. Hazardous mixtures were defined, and improved safety controls were derived. 

During casting of small ingots, one developed a leak (bleed-out) and contacted water near an unpainted (slightly rusty) steel plate. An explosion resulted... 

During casting of 37-cm ingots, due to a failure of equipment, molten aluminum was allowed to flow into water (depth unknown). An explosion resulted. The equipment was coated with an approved material, but some bare areas may have been present. Also there were external shocks from equipment falling against the vessel with aluminum and water Failure of a flow-metering rod in a casting operation led to the flow of aluminum into a pool of water. Two separate explosions resulted... 

In the casting of an aluminum alloy, one of the molds did not seat properly. A workman began to hammer it down when an explosion occurred. Water had apparently entered the mold by splashing up. The effect of pounding the mold is not known... 

In 1888, the American, Professor C.E. Munroe (Ref la), while working at the Naval Torpedo Station at Newport, Rl, observed that if a block of cast high explosive with letters indented on the surface was placed with the letter-side against a metal plate and exploded, the letters would be reproduced indented on the metal plate. This phenomenon was explained by the fact that two or more explosive waves will resolve into a resultant wave which is of much greater force than any of the original waves. 

The hypothesis was borne out by quantitative studies of the burning of explosives under confinement. Macek Gipson (Refs 7, 8 13) investigated burning of cast Pentolite and DINA, while Griffiths Groocock (Ref 10) experimented with low-density granular PETN, RDX HMX... 

Mr. Dunkle s Note Detonation velocity of Picric Acid is given in PATR 1740, Rev 1, as 5270 at density of 1 and 7350 at density 1.6 (cast). Roth s formula would give, for V, 319 at density 1, and 1131 at density 1.6 Refs 1) W. Friederich, SS 28, 244-47(1933) (On the detonation of explosives) 2) L. Medard M. Cessat, MAF 23, 195-203(1949) (Normalized investigation methods for explosives) 3) A.LeRoux, MP 33, 283-321 (1951) (Detonation of explosives by impact of projectiles of high velocity) 4) J.F. Roth, liber den Widerstand eines Spreng-stoffes gegen seine Detonation Deutung der Versuche von LeRoux (Ch the Resistance of an Explosive to its Detonation. Interpretation of Experiments of Le Roux),... 

For direct comparison of explosives, it is frequently convenient to select pj-=1.0g/cc. While the actual vel of a given chge may be measured with present methods with an accuracy of ca 0.1%, the D(pj) curve is seldom known this accurately, owing to fluctuations in density of the chge and exptl error in the evaluation of p. In cast, pressed and liquid expls, it is possible to determine density very accurately, but in loose, granular chges an accuracy better than 2.0% is seldom attained. For this reason the literature frequently shows discrepancies of this magnitude in D pj° and M factor of eq 3.1. Table 3.1... 

HTA-3 (USA). Designation of expl mixt consisting of HMX 49, TNT 29 Al 22% (Type I) HTA-3, Type II contains HMX 49, TNT 28.65, Al 22 Ca silicate 0.35% mw 91, OB to C02-21% cast, sp gr 1.90 Brisance by Sand Test 61.3g crushed in 200g Bomb Detonation Rate for cast unconfined 1.0 inch diam chge 7866 m/sec Explosion Temperature ca 370° (flames erratically at 5 secs) Friction Pendulum Test-unaffected by fiber or steel shoe Gas Volume Evolved on Explosion 680cc/g Heat of Combustion 3687cal/g Heat of Explosion 1190 cal/g Heat of Formation, no value reported ... 

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