Meyer R., Koehler J., Homburg A. Explosives. Wiley-VCH, 2002 / Explosives 5th ed by Koehler, Meyer, and Homburg (2002)

Cap Sensitivity	50

In Germany the following test for sensitivity to explosive caps has been developed:

Fig. 7. Cap test (dimensions in mm)

The explosive is placed into a cardboard tube, 200 mm long, inside diameter of 80 mm, wall thickness between 1.3 and 1.4 mm. One end of the tube is sealed by a thin cardboard disk, which is glued into position. The density of the filling charge is determined by weighing (increase in weight after filling volume 1005 cm3). The cap sensitivity can be influenced by the density of the charge. The test sample is placed upright onto a steel plate of 1 mm thickness, which is placed on a steel ring 50 mm in height, inside diameter of 100 mm, and wall thickness of 3.5 mm. A European test fuse (0.6 g PETN secondary charge) is inserted from the top throughout the full length of the tube, and initiated. No change in the condition of the plate or denting with or without fissure is classed as non-detonation. A circular hole indicates detonation.

51			Carbamite
Table 2. Cap test results.
Composition	Loading		Test Result:
	Density		Detonation
			g/cm3
ANFO, porous prills	0.79	– 0.93	none
AN cryst. with
TNT and fuels	0.82	–1.07	always +
AN cryst. with
TNT, DNT and fuels	0.82	–1.07	always +
AN cryst. with
DNT and fuels (NCNs)	0.75	–1.10	always +*)
AN porous prills
coated with DNT	0.82	– 0.84	none
AN cryst. with fuel	0.62	–1.10	not at higher densities
AN cryst. with Al,
earth alkaline
nitrates, fuels and
water (slurries)	1.13	–1.26	+
(also with TNT)	1.37–1.60		none

AN = ammonium nitrate

The results are unchanged when explosives are tested at increased temperatures (30 °C). An exception to this are the AN prills coated with DNT.

DNT diffuses into the pores, the explosive becomes more homogeneous and therefore more sensitive. No change occurs when the European test fuse is replaced by a No. 8 detonator (0.75 g Tetryl).

A similar test has been developed in the USA (according the deformation of a lead block, using commercial caps with 0.4 – 0.45 g PETN). It is advisable to classify according to test results and not, as was the custom in the USA, by the classification of NCN according to the explosive composition. As indicated above, ANFO’s are not cap sensitive; mixtures of finely ground ammonium nitrate containing only 2 % instead of 6 % of oil or wax can, however, be cap sensitive.

Carbamite

Denomination frequently used in English for W Centralit I.

* NCN-explosives can be non-cap-sensitive at somewhat higher densities.

Carbene	52

Carbene

Karben; Cuprene; Carb`ene

empirical formula: C12H10 molecular weight: 154.2 oxygen balance: – 300.9 %

Carbene or cuprene are technical names for polyacetylene. It is obtained as a cork-like substance, which is in a very fine state of dispersion, by polymerizing acetylene on copper catalysts.

The product is a suitable oxygen acceptor in W Liquid Oxygen Explosives. It has also been employed as an additive in fast-burning double base propellants.

Cardox

A physical explosion process which, like the Armstrong process and Airdox process, operates on the principle of a sudden release of compressed gas by means of a bursting disc. In the Cardox process, condensed CO2 is brought to a high vapor pressure by means of a heating cartridge.

Cartridge

Patrone; cartouche

This term denotes any quantity of an explosive material or functional formulations thereof, which has been sheathed in order to improve handling, loading or dosing; for ammunition, “cartridge” most often means an assembly of an W Igniter, a W Propellant charge and a projectile, which may itself contain a high explosive charge with ignition mechanism. As applied to industrial explosives, the term “cartridge” denotes the amount of the explosive – which may vary between 50 g and several kg – enclosed in an envelope which is usually cylindical-shaped, and is made of paper, cardboard or plastic.

53	Case Bonding

Cartridge Density

Patronendichte; densit´ de cartouche

(W Loading Density) In industrial explosives, the ratio between the weight of an explosive cartridge and its volume.

Some manufacturers indirectly give the cartridge density on the package by stating the number of standard 1 1//4 V 8c cartridges contained in a 50-pound case. The relationship is given in the following table:

Table 3. Cartridge density, weight of 1 1//4 V 8c cartridge and number of 1 1//4 by 8c cartridges in 50-pound case

Density	Weight of	Number of	Density	Weight of	Number of
	1 1/4 V 8c	1 1/4 V 8c		1 1/4 V 8c	1 1/4 by 8c
	Cartridge	Cartridges		Cartridge	Cartridges
g/cm3	g	in 50-pound	g/cm3	g	in 50-pound
		Case			Case
0.62	100	227	1.18	190	120
0.68	110	206	1.24	200	114
0.75	120	189	1.31	210	108
0.81	130	175	1.37	220	103
0.87	140	162	1.43	230	99
0.93	150	151	1.49	240	95
0.99	160	142	1.55	250	91
1.06	170	134	1.62	260	87
1.12	180	126	1.68	270	84

Cartridge Strength

Synonymous with W Bulk Strength.

Also W Strength; W Weight Strength.

Case*)

Brennkammer; chambre de combustion; also: Kiste; caisse

Pressure vessel designed to contain propellant charge before and during burning.

Also: a large shipping container for explosive materials.

Case Bonding

This expression denotes a modern processing technique in the field of rockets driven by solid propellants. The pourable W Composite Pro-

* Text quoted from glossary.

Caseless Ammunition	54

pellant is cast directly into the combustion chamber, which has been pre-treated to produce a bonding and insulating layer and is allowed to harden (cure) in the chamber. Since temperature variations may be expected to produce major stresses, owing to the different values of thermal expansion coefficients, the success of the method depends to a large extent on the bonding forces acting between the bonding and insulating layer and the metal wall on the one hand, and the hardened propellant on the other, as well as on their elastomeric stress relaxation capability.

Caseless Ammunition

Hülsenlose Munition; munition sans douille

The requirement to improve portable firearms resulted in a reduction of the caliber (dimension 4 – 5 mm); and to reduce the ammunition weight led to the caseless ammunition project. Moreover, in the event of a crisis the problem of a worldwide shortage of nonferrous metals for cartridge cases will arise.

For a considerable time the caseless ammunition consisted of a compressed NC propellant body into which the bullet was inserted. However, this propellant tends to self-ignition even at relatively low temperatures (ca. 170 °C). Thus a “cook-off” may result, i.e. a premature ignition in a hot cartridge chamber which may occur with all automatic guns. In addition, with caseless ammunition the heat which is otherwise transfered to the cartridge case remains in the cartridge chamber. Therefore, in order to avoid the “cook-off”; HITPs (High Ignition Temperature Propellant) have been developed worldwide. DNAG used such a propellant for the first time with caseless cartridges for a newly developed gun (G 11) from Messrs. Heckler & Koch. The essential innovations with regard to previous developments are the use of a high-temperature-resistant, non-crystalline explosive as binding material, a special granular shape for the main energy component and the possibility to adjust the interior ballistics by porosity and stability of the propellant body. Further new developments are the combustible primer and the booster.

Fig. 8. Sectional view of the caseless cartridge body (Calibre 4.73 mm) for the G 11 weapon system.

55	CDB Propellants

Casting of Explosives

Giessen von Sprengladungen; coul´ee de charge de projectiles

Since the brisance of an explosive largely depends on its loading density, the highest possible loading densities are employed, in particular for military explosives. This density is attained by casting or pressing. The pressing operation requires a technical device. A cast charge is easier to fit into shells, mines and bombs, which have rather complex-shaped internal profiles.

Since W TNT is pourable at 80 °C (176°F), it is highly important in military technology. Since a considerable contraction takes place when the liquid explosive solidifies, good care must be taken during casting to ensure free access to all parts of the cast which have not yet solidified, in order to ensure proper replenishment of liquid material. Formerly, this was done by simple manual poking, but many automatic devices have been developed which do not involve any manual labor and which yield cavity-free casts.

Pure TNT tends to form very long, needle-shaped friable crystals, with a loose texture which does not correspond to the maximum density. Cast TNT charges must be fine-crystalline, mechanically firm and dense, with numerous crystallization nuclei; i.e., solid TNT must be finely dispersed in the cast. According to BOFORS, the texture of the cast can be improved by the addition of W Hexanitrostilbene.

Casting of Propellants

Giessen von Triebsätzen; coul´ee de propergols

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:

a) hardening of polycondensates (e.g. polyurethanes or epoxys) with mechanically incorporated oxidizers, e.g. ammonium perchlorate (W Composite Propellants); the hardened plastic material acts as fuel for the oxidizer;

b) converting of pourable nitrocellulose granules by treatment with liquid nitrate esters (e.g. with nitroglycerine). The granules can be poured dispersed in the liquid (“slurry casting”), or filled in the rocket motor shell and gelled in situ with the added nitrate ester.

CDB Propellants

W Composite Propellants.

Centralite I	56

Centralite I

diethyldiphenylurea, symm. Diäthyldiphenylharnstoff; di´ethyldiph´enylur´ee; Ethyl Centralite; Carbamite

colorless crystals

empirical formula: C17H20N2O molecular weight: 268.4

energy of formation: – 68.2 kcal/kg = – 285.6 kJ/kg enthalpy of formation: – 93.5 kcal/kg = – 391.5 kJ/kg oxygen balance: – 256.4 %

nitrogen content: 10.44 % density: 1.112 g/cm3

melting point: 71.5 – 72 °C = 161 –162°F boiling point: 326 – 330 °C = 618 – 625°F

Centralite I, II and III are used as W Stabilizers in gunpowders, especially in nitroglycerine powders (W Double Base Propellants). It is insoluble in water, but soluble in organic solvents.

Centralites are not only stabilizers, but gelatinizers as well. The latter property is taken advantage of in solvent-free manufacture of double base propellants.

Specifications

solidification point: not less than	71 °C = 160°F
molten material: bright clear pale liquid
ashes: not more than	0.1 %
volatiles: not more than	0.1 %
acetone solution:	clear,
	no residue
secondary and tertiary amines:
not more than	0.1 %
chlorides as HCl: not more than	0.001 %
reaction:	neutral
acidity: not more than	0.04 %

57	Centralite III

Centralite II

dimethyldiphenylurea; Dimethyldiphenylharnstoff; dim´ethyldiph´enylur´ee

colorless crystals

empirical formula: C15H16N2O molecular weight: 240.3

energy of formation: – 37.3 kcal/kg = –156 kJ/kg enthalpy of formation: – 60.8 kcal/kg = – 254 kJ/kg oxygen balance: – 246.3 %

nitrogen content: 11.66 %

melting point: 121 –121.5 °C = 250 – 251°F boiling point: 350 °C = 662°F

Specifications

same as for Centralite I, except

solidification point: not less than 119 °C = 246°F

Centralite III

methylethyldiphenylurea; Methyläthyldiphenylharnstoff; m´ethyl´ethyldiph´enylur´ee

colorless crystals

empirical formula: C16H18N2O molecular weight: 254.3

energy of formation: – 94.7 kcal/kg = – 396.1 kJ/kg enthalpy of formation: –119.1 kcal/kg = – 498.5 kJ/kg oxygen balance: – 251.7 %

melting point: 57– 58 °C = 135 –138°F

Specifications

same as for Centralite I, except solidification point: 57 °C = 135°F

Channel Effect	58

Channel Effect

Kanaleffekt

Interruption in the detonation of an explosive column because of the compaction of the cartridges which have not yet exploded due ro the gas shock wave front in the borehole. This happens very often if the borehole cross-section is large as compared to that of the cartridges.

Chlorate Explosives

Chloratsprengstoffe; explosifs chlorat´es

Explosive mixtures of alkali metal chlorates with carbon-rich organic compounds such as wood dust, petroleum, oils, fats and nitro derivatives of benzene and toluene; they may also contain nitrate esters.

Their strength is lower than that of ammonium nitrate explosives in powder form. Chlorate explosives must not be stored together with ammonium nitrate explosives, since ammonium chlorate, which is formed when these two substances are brought into contact, decomposes and explodes.

“Miedziankit” is the name of absorbent potassium chlorate particles, which are impregnated with a liquid fuel just before use, and then acquire explosive properties. Following the development of W ANFO, this explosive is no longer of interest.

Cigarette-Burning*)

Stirnabbrand; combustion en cigarette

W Face Burning

Circuit Tester (Ohmmeter)

Zündkreisprüfer; eprouveur;´ blasting galvanometer

Instrument for electrical testing of misconnected circuits. The current intensity used in the testing must be well below the minimum detonation intensity of the electric primer; the circuit tester is accordingly equipped with resistances at both poles. Only officially approved testers should be employed. The testers are of two kinds: conduction testers which show, by means of a visual indicator, whether or not current is flowing in the circuit, and ohmmeters which measure the resistance of the priming circuit.

* Text quoted from glossary.

59	Combustibility

Class A, Class B and Class C Explosives*)

Classification defined by the U.S. Department of Transportation:

Class A Explosives:

Explosives, which possess detonating or otherwise maximum hazard; such as, but not limited to, dynamite, nitroglycerine, lead azide, blasting caps and detonating primers.

Class B Explosives:

Explosives, which possess flammable hazard; such as, but not limited to, propellant explosives, photographic flash powders, and some special fireworks.

Class C Explosives:

Explosives, which contain class A or class B explosives, or both, as components but in restricted quantities.

Coal Dust

Kohlenstaub; poussi´ere

Mixtures of coal dust with air are explosive and their detonation by blasting must be prevented (W Permitted Explosives).

Column Charge*)

Gestreckte Ladung; file de cartouches

A charge of explosives in a blast hole in the form of a long continuous unbroken column.

Combustibility*)

Feuergefährlichkeit; danger d’inflammation

Capability of burning. Flammable. The relative combustibility of materials in storage is defined as: hazardous – materials that by themselves or in combination with their packaging, are easily ignited and will contribute to the intensity and rapid spread of a fire; moderate – materials and their packaging both of which will contribute fuel to a fire; noncombustible – materials and their packaging that will neither ignite nor support combustion.

* Text quoted from glossary.