DE2506885C1 - Treatment of high explosive molded molded parts - Google Patents

Description

The invention relates to a treatment of cast high-explosive molded bodies with a high proportion of at least one non-melted (solid) high-explosive explosive, in particular Hexogenic, in different grain sizes and a smaller proportion of at least one molten Explosives, especially TNT, with both heated explosives suspended and then Poured into a mold or into the warhead casing and the solid explosives there if necessary compacted and the suspension is pressurized, followed by cooling of the solid and molten explosives to room temperature takes place in particular in several stages.

Such a method for the production of high-explosive molded articles is described in German patent specification 12 07 842. Here are the following special process steps provided after pouring the melt into the casting mold:

a) Compaction of the solid explosive fraction of the suspension in the heated form by means of a hollow, also heated surcharge stamp, which is permeable at its end face;

b) after the solid explosive component has been compressed, the action of an atmospheric overpressure the molten portion and removal of the load stamp by this overpressure and

c) further pressurization of the molten fraction by overpressure of atmospheric pressure up to its solidification.

Highly explosive molded bodies produced in this way are used in particular as Shaped charges, of which a high power density, rotational symmetry, chemical-physical homogeneity and, in order to guarantee freedom from cracks, insensitivity to temperature fluctuations and mechanical ones Loads is required. Only the fulfillment of all these properties guarantees the formation of a flawless shaped charge spike with the highest penetration capacity. The compacting of the solid more valuable Hexogens creates the prerequisites for a high specific blasting performance. The homogeneity of the Charge and its absence of cracks result in a rotationally symmetrical collapse of the metal lining of the Hollow charge funnel, what in connection with the detonation wave steering, the type of lining and the liner angle to a pointed, elongated, powerful shaped charge spike with exactly one behind the other sequence of its particles leads.

As already indicated, extreme temperature fluctuations that the warheads in deserts and arctic regions are exposed to large internal tensions in the explosive charge shaped body and thus Cause cracking. This tendency is exacerbated by the fact that the chemical explosives has significantly greater positive and negative expansions than the warhead casing made of metal. In addition, the explosives as such are subject to aging phenomena relatively quickly in terms of their chemistry, which mainly show up in the form of cracks. Especially longitudinal cracks and cracks in the front Part of the load, i.e. in the vicinity of the hopper lining, have a devastating effect on the Formation of a powerful spike than the local detonation front in the area of the longitudinal cracks rushes ahead and thereby a rotationally asymmetrical collapse comes about that dissipates one Brings sting with only a fraction of the intended penetration capacity.

Research and tests have confirmed that various parameters in the casting process production of shaped charges is responsible for their insensitivity to cracking and mechanical strength are. So it is known that when the TNT melted in the explosive suspension solidifies (Melting point 80.6 ° C), depending on the temperature level of the crystallization point, different Develop crystal forms of TNT with different properties. Is the crystallization point above 70 ° C, e.g. B. at 75 ° C, elongated, coarse TNT crystals are formed with good connectivity to the neighboring hexogen grains and very little susceptibility to internal stresses Due to high temperature fluctuations and external violence, e.g. B. during loading and during

INSPECTBO

the transport of the warheads. In contrast, crystallizations with a low solidification temperature z. B. 50 to 65 ° C, unsatisfactory results or crack-prone charges, because this is a fine crystalline Structure arises. The decisive parameters for controlling the temperature level of the solidification point for the TNT melt are the maximum temperature limit of the molten TNT and the holding time during which the already melted TNT remains at this maximum temperature. This is the casting temperature, with which the heated suspension is poured into the molds or into the warhead shells. try have shown that too long a holding time at casting temperature, e.g. B. over 4 hours, the freezing point after lower temperatures (below 70 ° C) it is laid in the same way as a casting temperature that is too high, the for this reason 95 ° C, not at most 100 ° C should exceed.

As further investigations have shown, are in favor of crystallization when the melt cools down so-called crystallization nuclei responsible, from which the crystal formation starts and then very quickly expires. It is believed that the crystallization nuclei themselves are in the liquid phase Remaining single crystals or crystal residues that only last a limited period of time and only up to a certain time Temperature above the melting point exist and then disappear entirely. There is one Interaction between the temperature level and the holding time for the heating temperature, d. i.e., the higher this The heating temperature for melting the less valuable explosives or the casting temperature is, the shorter the holding time during which the melt can remain at this temperature must be to allow crystallization nuclei to »survive« in the melt. Conversely, the longer the required Holding time, the lower or less high above the melting point the heating temperature (casting temperature) lie.

On the other hand, however, there is a requirement, especially in the industrial mass production of warheads, for the highest possible casting temperature to keep the suspension easily pourable (easy to pour), which already results in a casting with a better pourable structure and denser sedimentation is achieved. TNT melts at 80.6 ° C. The tolerance zone for the Achieving the highest possible crystallization point upwardly limited (as low as possible) heating temperatures on the one hand and for those required in terms of the ability to pour the explosive suspension Casting temperatures (as high as possible), on the other hand, should be considered in industrial mass production on economic, d. H. As large as possible pouring quantities (batches) not too broad. Also still plays how already mentioned, the holding time for the casting temperature plays a decisive role, because the melt must during the entire pouring time, even when the last of the molds is poured full, and furthermore during the subsequent sedimentation, the load compaction and the atmospheric compaction of the individual suspensions of explosives are kept liquid in the molds above their solidification point.

However, it has now been shown in the industrial mass production of high-explosive molded articles that that compliance with the required relatively tight manufacturing tolerances with respect to the mentioned Temperature limits and constant heating times, due to the different chemistry of the starting materials, the apparatus fluctuations and the permissible dimensional and measurement inaccuracies of the used Devices, is not always possible. On the other hand, for understandable reasons, the full military The effectiveness of each warhead in the event of an emergency must also be guaranteed on the cargo side.

The object of the invention is therefore to use special measures for cast explosive charges of the type mentioned at the beginning, their full military

ίο to ensure effectiveness and efficiency still to be improved or increased.

This object is achieved according to the invention in that the explosive molded body after Solidification of its melt, d. H. after only partially cooling to room temperature, again to a little is heated above the melting point of the explosives to be melted during manufacture, that this treatment temperature is only for a relatively short time during which the melt is liquid, is held and that the shaped explosive body is then cooled relatively slowly to room temperature.

The inventive treatment of the shaped explosive body can therefore after its solidification Melt either carried out during the cooling process, which is interrupted in the process so that the treatment method according to the invention is integrated in the entire manufacturing process, or be practiced after cooling the shaped body to room temperature, so that quasi a Post-treatment process is available.

The following (post) treatment steps or times according to the invention have been found in a warhead caliber of about 100 mm and shown to be preferred for a load consisting of hexogen and TNT:

The shaped explosive body goes back from room temperature to 81 ° to 90 ° C, in particular to 85 ° C heated, this heating period being 2 to 4 hours, in particular 3 hours; the constant post-treatment temperature is maintained for 0 to 1 hour, in particular 1/2 hour, and the cooling period on Room temperature lasts 12 to 14 hours, especially 13 hours, with the cooling down in stages can take place and a holding time is inserted at 75 ° C, during which the melt completely solidifies to Avoid tension in the cargo body.

The proposed treatment process guarantees that the permissible heating temperature and the permissible holding time at this temperature, to then one when the melt is subsequently cooled

to get the highest possible crystallization point, can be clearly observed, d. h that The melt only needs to be liquefied and can then be slowly cooled down again.

According to the invention, it is also possible to proceed in such a way that the shaped explosive body several times in succession Is melted, because experiments have shown that the crystallization point by a few Degrees Celsius is raised, provided that during the actual production due to particularly unfavorable circumstances the crystallization point has set itself very low, which leads to a very unfavorable fine-crystalline structure has led.

The invention therefore provides a means at hand, depending on the crystallization point of an explosive melt Need to be raised afterwards in order to achieve the desired structure with the properties required for the To receive charge. The desired coarse, elongated TNT crystals are inherently and by theirs

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good adhesion to the neighboring Hexogenkör- charge with it, so that their homogeneity once again

nern is increased in later extreme temperature fluctuations. This increases the efficiency of the

not susceptible to further cracking. In addition, charge due to the evenness of the detonation front

due to the targeted, very slow and perfect collapse formation of the funnel lining

Cooling internal stresses in the Sprengstofformkör- ^r> dung. In addition, the mechanical strength of the

per avoided at all. Furthermore, the inventive charge demonstrably increased by about 10%,

Appropriate treatment a more even distribution. Instead of hexogen, octogen and in place

of the explosives to be melted within the TNT, trinitrobenzoi can be used.

Claims (3)

Patent claims: 1. Process for the treatment of cast high-explosive molded articles with a high Share of at least one non-melted (solid) high-explosive explosive, in particular Hexogenic, in different grain sizes and a smaller proportion of at least one molten Explosives, especially TNT, with both heated explosives suspended and then in a mold or poured into the warhead shell and there the solid explosives optionally compressed and the suspension is pressurized, whereupon the cooling of the solid and molten explosives at room temperature, especially in several stages takes place, characterized in that the explosive molded body after its solidification Melt, d. H. after only partial cooling to above room temperature or after complete cooling up to room temperature, again to a little above the melting point of the material to be melted during manufacture Explosives portion is heated beyond that this treatment temperature only for a relative a short time during which the melt is liquid, is held and that then the explosive molded body is cooled relatively slowly to room temperature. 2. The method according to claim 1, characterized in that the consisting of hexogen and TNT Explosive molded body is reheated from room temperature to 81 to 90 ° C, in particular to 85 ° C and this heating period is 2 to 4 hours, in particular 3 hours, that the aforementioned constant post-treatment temperature 0 to 1 hour, in particular 1/2 hour is maintained and that the cooling period to room temperature lasts 12 to 14 hours, in particular 13 hours, and the cooling takes place in particular in stages. 3. Treatment of shaped explosives, marked by repeated application of the method steps according to claim 1 or claim 2.