RDX detonation

CA 55, 24011(1961) (Equation of state of the products in. RDX detonation) Mj) W. Fickett, "Detonation Properties of Condensed Explosives Calculated with an Equation of State Based on Intermo-lecular Potentials , Los Alamos Scientific Laboratory Report LA-2712(1962), Los Alamos, New Mexico, pp 9-10 (Model of von Neumann-Zel dovich), pp 153-66 [Comparison of KW (Kistiakowsky-Wilson) equation of state with those of LJD (Lennard-Jones-Devonshire) and Constant-/ ] M2) C.L. 

Detonation Transients and Unstable Detonation Processes. Allen et al (Ref 1) made detonation velocity vs chge length. measurements on RDX (—65+100 mesh), fine grained TNT (—35 —150) coarse, low-density TNT (—8+10) 50/50 fine-coarse TNT, cast TNT, low-density. mixts of 80/20 TNT/AN, and mixts of 90/10 AN/RDX. Deton velocities were measured by a rotating mirror streak camera and by the pin oscillograph technique, in most cases simultaneously Their exptl data showed six different types of velocity transients ... 

IV. Characteristics of Steady Detonation V, Initiation Behavior VI. Deflagration-to-Detonation Transition (DDT) and Combustion VII. Decomposition and Kinetics VIII. Analytical Methods IX. Waste Disposal X. Toxicity XI. RDX Detonators XII. Military Specifications and XIII. References. Major emphasis will be placed on Sections IV, V, and VI... 

Their rather complex equation of state (EOS) for RDX deton products is given below (DP = detonation products) ... 

A recent article (Ref 50 see Table 1 of Subsection A above) lists a=T. 1mm for 1.44g/cc RDX. Addition of various liqs generally increases the reaction zone width, as shown in Table 1 F. Characteristics of RDX Detonation Products. Volk (Ref 105) measured the fumes produced by the deton of RDX by gas chromatographic and chemiluminescence techniques. He identified h2, n2, co2, co, h2o, ch4, c2h6 c2h4... 

Sensitivity Very low (requires RDX detonator for initiation) Classification Secondary explosive... 

Both RDX and HMX are stable, crystalline soHds, somewhat less sensitive to impact than PETN. Both may be handled with no physiological effect if appropriate precautions are taken to assure cleanliness of operations. Both RDX and HMX detonate to form mostiy gaseous, low molecular weight products and some intermediate formation of soHd carbons. The calculated molar detonation products of RDX are 3.00 H2O, 3.00 N2, 1.49 CO2, and 0.02 CO. RDX has been stored for as long as 10 months at 85°C without perceptible deterioration. 

Tetiyl. 2,4,6-Trinitrophenylmethylm tramine (tetryl) was used ia pressed form, mostly as a booster explosive and as a base charge ia detonators and blasting caps because of its sensitivity to initiation by primary explosives and its relatively high energy content. Properties are presented ia Table 11 (173). Batch and continuous processes for the production of tetryl have been developed. Tetryl is no longer used ia the United States and has been replaced by RDX (174-178). 

The incorporation of aluminum increases the blast effect of explosives but decreases the rates of detonation, fragmentation effectiveness, and shaped charge performance. Mixes with aluminum are made by first screening finely divided aluminum, adding it to a melted RDX—TNT slurry, and stirring until the mix is uniform. A desensitizer and calcium chloride may be incorporated, and the mixture cooled to ca 85°C then poured. Typical TNT-based aluminized explosives are the tritonals (TNT + Al), ammonals (TNT, AN, Al), minols (TNT, AN, Al) torpexes and HBXs (TNT, RDX, Al) (Table 14) (223-226). 

TNT Al wax 47 31 22 5). Three MEDINA-contg formulations were compared with std expls in plate dent, air blast, underwater blast, and fragn tests. MEDINA showed a 4% improvement over RDX in shaped charge penetration (Ref 14). MEDINA was tested as a detonator fill, but was unsatisfactory due to poor stability (Ref 14)... 

Use, RDX (60g) is stirred into 40g of molten N-methylpicramide at 120° to give a castable expl, deton rate 7750m/sec, vacuum stab better than Cyclotol (Ref 20)... 

Its impact sensitivity was comparable to RDX, and the Trauzl Pb block expansion was found to be 130 (PA 100). The rates of deton of 30mm diameter charges in cardboard tubes were 5630m/sec at d 1.10g/cc,6970m/sec at 1.50g/cc, 7560m/sec at 1.60g/cc, and 7830m/sec at 1.65 g/cc. Medard concluded that Methylglucoside... 

A new compn was developed consisting of RDX 35.9, NC (1-2.6% N) 24.5, NG 22.8, DNEtB 10.0, DBuPh 6.6 DPhA 0.2%. It was tough and thermally stable, relatively non-hygroscopic, and insensitive to friction, impact and rifle fire. It was also superior to TNT in rate of detonation and brisaiice. A relatively simple and non-hazardous procedure was developed for its manuf. Another formulation variation was TNT 35, Comp A-3 35, M-l proplnt powder 20, and DNEtB or TEGDN 10%. This was hard and tough at room temp, but softened at 65° (Refs 1 3)... 

RDX and Nitrocellulose, no detonation occured. Similar experience has been reported at the US Naval Ordnance Station, Indian Head, Md (Ref 3) in over 100 irradiations with 40mg samples of RDX, HMX, anhydrous hydrazine and composite propints... 

Development work by the US Navy has included attempts to use expls other than RDX and HMX viz, HNS and TACOT (Tetranitro-1,2,5,6-tetraazadibenzocyclooctatetrene) together with binders such as RTV silicon rubbers. As reported by Stott (Ref 43) such work was not fruitful because of the low deton vel and d of the developed compns... 

A series of papers by. Menichelli Yang (Refs 82, 84 86) showed that Q-switched ruby lasers could initiate steady detonation in PETN (and RDX or Tetryl) in <0.5 psec when a lOOOA-thick Al layer was deposited on the face of the sample, and subsequently exposed to laser radiation of 0.5 to 4.2 J with a pulse width of 25nanosec... 

In the case of initiating expls, the requirements are the same as in (4) except that a hot flame is not required, but rather that it produce a shock wave strong enough to detonate a HE such as Tetryl, PETN, RDX, PA, TNT, etc... 

Pb Azide (LA), which is the most important expl used in detonators (Ref 11), although extremely sensitive to shock, heat, and friction, is not sufficiently sensitive to stab action to insure 100% reliability in firing from the stab action. Consequently, the priming mixt is used as a first-fire layer in these units. RDX (cyclotri-methylenetrinitramine), also known as Cyclo-nite, is contained as the output charge of the typical stab detonator. Its output results in a detonation of other expls (Ref 11)... 

Both the Pb disc test and the steel dent test are of particular significance to stab detonators. As a matter of illustration, the steel dent test (Ref 10) consists of firing a detonator in direct end-on contact with a steel block. The depth of the dent produced is a measure of output. The depth, or better, the volume of the dent correlates well with initiation effectiveness. The low-rate detonation, which crushes nearly as much sand as high-order detonation, makes no dent in a steel plate. It has been demonstrated that the depth of the dent is proportionate to the excess of pressure over the yield strength of the steel of the dent block, integrated over the volume of the detonation head. It has been found that a detonator of 0.190-inch diameter or larger, which produces a dent 0.010 of an inch deep in a mild steel block, will initiate a lead of Tetryl or RDX under favorable conditions. Specification requirements for detonators to be used in fuses are usually at least 0.015 to 0.020 inch in depth, and many produce dents up to 0.060 inch deep... 

The base charge of stab detonators had usually been Tetryl but present designs use RDX... 

Threshold shock pressures to initiate detonation in several SP are shown in Table 55. In general, unless the SP contains solid HE ingredients such as HMX or RDX, the threshold pressures are considerably greater than for solid HE at a comparable degree of compaction. Even so, the pseudo-composites of AP/wax must be considered to be rather shock-sensitive provided their degree of compaction does not exceed about 90% of their theoretical max density (TMD), Figure 21 shows that up to about 90% TMD the shock sensitivity of an 80/20 AP/wax composite is very similar to that of TNT... 

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