19-08-2013, 04:56 PM
Explosion welding
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Abstract
Explosion welding or bonding is a solid-state welding process that is used for the metallurgical joining of dissimilar metals. The process uses the forces of controlled detonations to accelerate one metal plate into another creating an atomic bond. Explosion bonding can introduce thin, diffusion inhibiting interlayers such as tantalum and titanium, which allow conventional weld-up installation. In addition, explosive welding is considered a cold-welding process, which allows metals to be joined without losing their pre-bonded properties.
This paper describes work carried out to numerically analyse a two plate welding process using a finite element method (FEM) and the verification of the results using experimental data. The numerical simulations identify factors such as the level of strain induced in the plates and the direction of the shear stress at the collision zone, in the surface of flyer plates as indicators of bond strength. The phenomenon of jetting is computationally reproduced.
Explosion welding is a solid-state process that produces a high velocity interaction of dissimilar metals by a controlled detonation , Oxides found on material surfaces must be removed by effacement or dispersion, Surface atoms of two joining metals must come into intimate contact to achieve metallic bond
Introduction to Explosive Welding
Explosive welding is a solid state welding process, which uses a controlled explosive detonation to force two metals together at high pressure. The resultant composite system is joined with a durable, metallurgical bond. Explosive welding under high velocity impact was probably first recognized by Garl in 1944. Explosive welding was first recognized as a possibility in 1957 in the United States when it was observed by Philipchuck that metal sheets being explosively formed occasionally stuck to the metal dies. Between that and now the process has been developed fully with large applications in the manufacturing industry.
Principle of Explosion
Cladder metal can be placed parallel or inclined to the base plate
Explosive material is distributed over top of cladder metal
Upon detonation, cladder plate collides with base plate to form weld
It has been found to be possible to weld together combinations of metals, which are impossible, by other means. This is a solid state joining process. When an explosive is detonated on the surface of a metal, a high pressure pulse is generated. This pulse propels the metal at a very high rate of speed. If this piece of metal collides at an angle with another piece of metal, welding may occur. For welding to occur, a jetting action is required at the collision interface. This jet is the product of the surfaces of the two pieces of metals colliding. This cleans the metals and allows to pure metallic surfaces to join under extremely high pressure. The metals do not commingle, they are atomically bonded.