Pressing density

The deton vel of powders is a smooth function of the granular density or of the pressing density and for a large chge diam it does not depend on the dimensions of the expl particles. It is precisely from the dependence of D on p for powders that one can establish the equation of state of the products. Thus, it would not be correct to state that in expl combstn the deton vel is equal to the vel of the gas jets which penetrate the powd. In actuality, upon detonation by the mechanism of explosive combustion, the deton vel is detd by the equation of state. That is, by the pressure of the expln products according to hydro-dynamic theory, while the vel of the gas streams in this case is automatically established equal to the deton vel... 

RDX/Al/mononitronaphalene 80/15/5 which had a bulk density of 1.05g/cc and a pressed density of 1.70g/cc at 2100 kg/sqcm. Its CUP or modified Trauzl test value is 156% of PA, sensitivity to shock with a 2kg weight 200cm is 44% explns, and velocity of detonation 7990 me ters/sec... 

Sevranite No 1 (Ref 16). RDX (or PETN) 48, NH4C104 31, powd Al 3 plasticizer (1 p polyvinyl chloride in 17 parts liq DNT) 18%. This compn at a pressed density of 1.70 g/cc has a velocity of deton of 7000 meters/sec. It can be kept under water for several weeks without any effect on its expl power. The CUP value is 142% of PA... 

Table 1, taken from the ref, lists the measured linear (a) and cubic (0) expansion coefficients of expls and binders along with their glass transition temps and pressed densities. The cubic expansion coefficients (0) can be calcd for isotropic materials as J3 = 3a... 

Explosives and Binders Coefficients of Thermal Expansion CTE, Glass Transition Temperatures Tgr and Pressed Densities... 

One of the crystal forms of NQ (Figure 3.31) is fiber- or featherlike this enables the crystals to mechanically interlock with large void spaces left between them. This property enables NQ to maintain fairly decent mechanical properties (it does not flake or fall apart) at low pressing densities. The ability to maintain uniform low density makes NQ a useful laboratory explosive where some experiments require controllable low detonation velocity and pressure. NQ is made by dehydration of guanidine nitrate, which in turn was made by the reaction of ammonium nitrate with dicyanodiamide. NQ is also used as a major ingredient in triple base gun propellants. 

Since most EBW detonators utilize approximately the same PETN particle size and surface area, and are loaded at approximately the same initial pressing density, Eq. (25.9) can be approximated by... 

The discrepancy of the calculated to measured ib,h in Table 25.1 is probably due to differences in initial pressing density, as well as possible differences in particle size and or specific surface area of the PETN. 

Press density By measuring the height of a cylindrical ASTM No. B 331-85... 

Due to the friction between the powder and the die wall and the nature of the load distribution inside the die, the pressing density is not the same all over the compact. This is more pronounced for large parts and large part heights and can lead to crack formation and/or distortion of the pressed compact during sintering. Large and critical parts are therefore commonly pressed isostatically. 

Apparent density (scott density) and press density. (For determination methods, see Table 5.12.)... 

Table 1 (continuation) Linear CTE (a) Cubic CTE (jS) Pressed Density... 

Fig. 5.17 Densification behavior and the resistivity vs. press density of Super P Li and acetylene black...

Casting runs were also made using fine-grained Vesuvius AA slalon powder, This material was dried, debindered, and sintered to a density of 3.13 g/cm3 (the range of values for four specimens was 0.006 g/cm ), This Is 97.5% of the theoretical density for this composition and more then 99% of the hot-pressed density according to manufacturer s data. 

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