Melt casting

Considerable work has also been conducted to try to find thermoplastic elastomers that can be used to simplify processing by enabling dry blending and melt casting instead of the conventional mixing and curing process (see Elastomers, synthetic). 

Copper alloys can also be grouped according to how the principal elemental additions affect properties. This grouping depends primarily on whether the additions that dissolve in Hquid copper can form discrete second phases during either melting/casting or in-process thermal treatment. AHoy constitution that relates to limits of soHd solubiUty and equiUbrium phases that form in binary and ternary combinations with copper are found in the Hterature (2,3). 

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. 

Most current expl fills are blends of TNT with other ingredients, and are melt-cast loaded into bombs and warheads. Typically, several thousand pounds of the flaked blend are charged to a stirred melt kettle and heated to just above the melting point of TNT. It forms a mobile slurry when molten, and is poured mto the empty bomb or shell cases, where it solidifies. Additional ingredients such as Al may be added in the melt kettle, depending on the particular formulation being poured and the particular munition product... 

Meldrum s acid chemistry, 21 151,152, 153 Melengesterol acetate (MGA), 10 871 Melissic acid, physical properties, 5 30t Melt behavior, of polycarbonates, 19 805 Meltblown fabrics, 17 478-479, 495 Meltblown fibers, 11 237, 240-241 Melt casting, 14 230 Melt crystallization, 3 137—141... 

Polystyrene insulation on magnet wire 0.49 Encapsulated with phthalic anhydride cured bisphenol A-epichlorohydrin epoxide (epoxy hot melt cast). Impregnated. 

A number of important explosives contain nitramino functionality in conjunction with nitrate ester or C-nitro functionality. A-Nitrodiethanolamine dinitrate (DINA) (7) is a powerful explosive which can be melt-cast into charges. A,2,4,6-Tetranitro-A-methylaniline (tetryl) (8) exhibits high brisance (VOD 7920 m/s, d = 1.73 g/cm ) and has found application in both detonators and boosters, in addition to being a component of some composite high explosives. 

The US Air Force formulation designated as AFX 644 (based on TNT and NTO and also referred to as TNTO IV) is used for low-vulnerability General Purpose (GP) bomb. AFX-644 is a melt-cast, wax desensitized nitrotriazolone (NTO)-based explosive formulation which employs TNT as an energetic binder and aluminum powder to enhance blast performance. TNT, NTO, wax and A1 powder are mixed in proportions of 30,40,10 and 20% respectively and meets the United Nations ... 

Organizations such as Giat (France), Denel (South Africa) and US Army s Pica-tinny Arsenal continue their efforts to develop IMs based on melt-cast TNT. It is acceptable for artillery ammunition (not for high performance warheads required for missiles) being cheaper in production than either pressed or cast-cured PBXs. 

Picatinny Arsenal, in association with ATK Thiokol and others, are in the process of developing PAX Series of explosive formulations and also a series of IM melt-cast explosives. They claim that the TM-ness is accomplished by dispensing with TNT completely and using dinitroanisole (2,4-dinitroanisole, DNAN) which is a yellow crystalline substance at room temperature [218, 230] and has a m.p. of... 

C. The formulation, PAX-35, is less sensitive but of comparable performance to Composition (TNT-based melt-cast explosive formulation). Also under development are pressed and cast-cured IM PBXs and important example is PAX-3. BAE Holstan Army Ammunition Plant (HAAP), USA has developed PAX-34 which has the following ingredients... 

The cured systems have a disadvantage, that is, once filled into a munition, they cannot be removed and munition re-filled, if the quality of the filling is found to be unsatisfactory. Munitions are sometimes re-filled with melt-cast formulations if the original filling is not of the required standard, but it depends on the cost of... 

Kosowski, B.M., and Taylor, R.C. (1995) Methods and compositions for melt-cast explosives, propellants and pyrotechnics. US Patent 5,431,756. 

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