FAULTY FUSIONS IN LARGE-SIZE EXPLOCLAD SHEETS AND DETONATION PARAMETERS OF EXPLOSIVES L. B. Pervukhin and O. L. Pervukhina

Defects which are caused with instability of a detonation of a chargelocal tear-out of clad material CHANGE OF THE DETONATION VELOCITY OR ATTENUATIONCHANGE OF EXPLOSIVE DENSITYMode of self-extending explosive process with the lowered power allocation Curvature of the detonation frontSharp local change of welding parameters (pressure, impact velocity, collision angle) worm-holes, faulty fusion clad metalLocal closed fault of shock-compressed gas area

Defects of continuity worm-holes , faulty fusions Sinuosities, cracks

Requirements to explosive for explosion weldingDetonation velocity explosive of in flat charges from 20 to 120 mm should be in the thickness no more than 3000 km/s.Explosive at charge packing should not will be condensed and compressed.Detonation stability of a flat charge remains on the big areas to 20 sq.m.Low cost explosive and possibility of its preparation in day of use from components not being an explosive material.

TNT +ammonium nitrate (1:1) ammonium nitrate +diesel oil (3%). Research of detonation process of the large-sized flat charges having a thickness close to critical for given explosive Thickness layer of inert material (sand)changed from d/2 to d

Material , Thickness, mmExplosiveThickness, mmDurability of joint, MPaContinuity of layers joint %ExplosiveSand.3 + .32,5 +20TNT +ammonium nitrate1:1300218100151531010082212590880010+081810100 + 12ammonium nitrate +diesel oil (3%)8004101005030430100305035080

Estimation of size of losses at a detonation of charges The closed cover of the explosive chamber allows to estimate change of energy which is allocated at a charge detonation on its deformation.

Camera deformation measured in several pointsTNT +ammonium nitrate (1:1) ammonium nitrate +diesel oil (3%). Thickness layer of inert material (sand)changed from d/2 to d

Acoustic influence on environmentMeasurement of a sound level by the device spent directly on range at performance of regular works on explosion welding of preparations in the size 42001200120 mm (400 kg of a mix). Sound level on distance of 1200-4000 m at explosion of explosive charges with inert material is less in 4 times, than without it. TNT +ammonium nitrate (1:1) ammonium nitrate +diesel oil (3%). Thickness layer of inert material (sand)changed from d/2 to d

Research technique of mixes of ammonium nitrate +diesel oil Definition of influence of type of ammonium nitrate and percentage of diesel oil on quality of their mix;Establishment of dependence of detonation velocity from quantity of diesel oil, a thickness of explosive and presence of an inert material (sand);Experimental check of a mode of explosion welding on large-sized charges Definition continuity of layers joint , structures and joint durabilities.

Microporous ammonium-nitrate + diesel oil from 2 to 16%Ground ammonium-nitrate + diesel oil from 2 to 16%Granulated ammonium-nitrate + diesel oil from 2 to 16%

Ammonium-nitrate structureMicroporous ammonium-nitrate granulesGranulated ammonium-nitrate granulesWetting of the granulated ammonium-nitrate by diesel oil is carried out by filling of roughnesses on a granule surface owing to what ability of their wetting is insignificant. Process of mixing is at a loss and there is a stratification in the course of storage. Ammonium-nitrate crushing before mixing with diesel oil considerably raises its wettability, however such mixes are condensed and compressed;Presence of a microporous in structure of ammonium-nitrate considerably increases the surface area of a granules of that allows to impregnate. It allows to impregnate and keep well diesel fuel for a long time.

Influence of thickness of charge and sand for velocity of detonation of mix NH4NO3+diesel oilThickness of charge Detonation rateContents of diesel oilInfluence of the contents of diesel oil on detonation rateof mix NH4NO3+ diesel oilUnder a sand layer the mix with the maintenance of diesel oil of 4 % steadily detonates in thickness of 20 mm with a velocity of 1480 km/s in charges in length of 6 m.Detonation rateUnder a sand layerWithout sand

ConclusionsFor stabilisation of detonation process of large-sized flat charges it is necessary to place a layer of an inert material on their surface. It reduces probability of occurrence defects.

Use as explosive at explosion welding of a mix of the granulated microporous ammonium-nitrate + diesel oil allows to reduce to a minimum application industrial explosive, to mechanise process of mix preparation, to provide high quality of welding for the account of stability of structure and charge density on all its surface. Speeds of a detonation of these mixes in the studied range of thickness of a charge are close to optimum from the point of view of joint formation at explosion welding.

ExplosiveBulk density, kg/m3Explosive layer thickness, mmDetonation rate, m/sMicroporous ammonium-nitrate + diesel(2-8%)740601770-2910Microporous ammonium-nitrate + diesel(4%)74040-802080-2740Microporous ammonium-nitrate + diesel ( 4%) +sand74020-801480-2400Granulated ammonium-nitrate + diesel oil(2-6%)90080-1002500-3400Ground ammonium-nitrate + diesel oil( 2-6%)850-90020-502500-3400