Explosive Forming Research Articles

The process of explosive forming of metal

The process of explosive forming of metal

Metal Working with Explosives

Explosive forming is a dynamic new method of metal working. Many operations such as forming, sizing, cutting, compacting, and welding can now be performed by the energy released from detonating or deflagrating an explosive. The author presents a summary of activities to date and horizons opening for the future.

爆発成形に関する研究

Recently, the explosive metal forming has begun to drau considerable attention of the public.The main reasons are the following :1. Larger or more complicated shapes than ever can be formed easily with explosives.2. Some new great-strength, high-temperature resistant metals can be formed only by ex plosive forming. in this report are included fundamental experiment about the under water explosive metal forming. That is, the relation between peak explosive pressure and weight of explosive, or distance from explosive, or depth from water level are ob tained by copper cylinder-type pressure gauge. Then, cylindrical cups of 50 mm dia, 20, 30, 40 mm depth, have been formed under several conditions and the formablity of explosive forming are estimated from these results.

The ignition mechanism of high explosives

A preliminary account of some theoretical and experimental results shows that an explosive becomes inflammable at compression if the air inclusions contain vapours or small particles or drops which, when heated, give an exothermic reaction. A similar effect is obtained if the explosive forms thin layers between two bubbles, or if the bubble wall is uneven with projecting convex sections.

Possible P-Q type variation in infectious laryngotracheitis virus.

FROM an outbreak of acute infectious laryngotracheitis in South Australia1 a strain of virus was isolated which proved to be highly resistant to neutralization by antisera in the pock neutralization test. On intratracheal inoculation into susceptible birds, it gave rise to typical acute infectious laryngotracheitis in about four days, produced a typical vaccination reaction when given by the cloacal route and gave rise to antibodies fully active against a type infectious laryngotracheitis virus. On primary isolation it showed some degree of resistance to neutralization by its homologous and other infectious laryngotracheitis antisera, but after storage for eight months in the ‘dry ice’ refrigerator it was almost completely resistant to neutralization by all available antisera (see table). Prior to this outbreak, infectious laryngotracheitis was not known to be present in South Australia despite a careful watch being kept, and no spread of the typical explosive epidemic form of the disease in other flocks has followed this outbreak. A survey of hens throughout South Australia showed that, at the time of isolation of this strain, about 50 per cent of the flocks had birds with demonstrable infectious laryngotracheitis antibodies in their sera.

STUDIES ON EXPLOSIVE ANTIMONY: III. THE MAGNETIC SUSCEPTIBILITY

Explosive antimony is not as diamagnetic as the ordinary polycrystalline metal. The magnetic susceptibilities are respectively −0.38 × 10−6 and −0.88 × 10−6. The explosive or amorphous form should therefore be regarded as a true glass of the supercooled liquid. The fact that it is less "metallic" than the molten metal cannot be the result of the metallic binding of the liquid or crystalline state changing to homopolar binding in the amorphous state.

Studies on explosive antimony. I—The microscopy of polished surfaces

In 1855 Gore reported the discovery of a peculiar soft and lustrous form of antimony obtained by the electrolysis of antimony trichloride solution. This deposit when heated or scratched underwent a sudden change in which a considerable quantity of heat was developed, the metal was badly shattered, and white fumes of occluded antimony trichloride were evolved. The metal after “explosion” was indistinguishable from ordinary antimony. Different aspects of the phenomenon have since been the subject of several investigations of which the most comprehensive is that carried out by Cohen and his co-workers during the years 1906–05. More recently Cohen and Coffin have succeeded in determining the factors governing the deposition of the explosive form, and Böhm, Steinwehr and Schulze, and Kersten have made X-ray studies of its structure.

Recent Contributions to the History of Detonating Agents 1

III. NOBEL has observed that if, instead of making use of the most explosive form of gun-cotton, or trinitrocellulose, a lower product of nitration of cellulose (the so-called soluble or collodion gun-cotton) is added to nitro-glycerine, the liquid exerts a peculiar solvent action upon it, the fibrous material becoming gelatinised while the nitro-glycerine becomes at the same time fixed, the two substances furnishing a product having almost the characters of a compound. By macerating only from 7 to 10 per cent. of soluble gun-cotton with 90 to 93 per cent, of nitroglycerine, the whole becomes converted into an adhesive plastic material, more gummy than gelatinous in character, from which, if it be prepared with sufficient care, no nitro-glycerine will separate even by its exposure to heat in contact with bibulous paper, or by its prolonged immersion in water, the components being not easily susceptible of separation, even through the agency of a solvent of both. As the nitro-glycerine is only diluted with a small proportion of a solidifying agent which is itself an explosive (though a somewhat feeble one), this blasting gelatine, as Nobel has called it, is more powerful not only than dynamite, but also than the mixture of a smaller quantity of nitro-glycerine with the most explosive gun-cotton, as the liquid substance is decidedly the most violent explosive of the two. Moreover, as nitro-glycerine contains a small amount of oxygen in excess of that required for the perfect oxidation of its carbon and hydrogen constituents, while the soluble gun-cotton is deficient in the requisite oxygen for its complete transformation into thoroughly oxidised products, the result of an incoporation of the latter in small proportion with nitro-glycerine, is the production of an explosive agent which contains the proportion of oxygen requisite for the development of the maximum of chemical energy by the complete burning of the carbon and hydrogen, and hence this blasting gelatine should, theoretically, be even slightly more powerful as an explosive agent than pure nilro-glycerine.