25-02-2013, 02:41 PM
Explosion Welding
Explosion.pptx (Size: 1.25 MB / Downloads: 341)
Basics
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
Advantages
No heat-affected zone (HAZ)
Only minor melting
Material melting temperatures and coefficients of thermal expansion differences do not affect the final product
The shock front compresses and heats the explosive material which exceeds the sonic velocity of undetonated explosives
Component Terminology
Base component
Joined to cladder
Remains stationary
Supported by anvil
Cladding metal
Thin plate in direct contact with explosives
Can be shielded by flyer plate
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
Placement of Cladder metal-parallel
Standoff distance predetermined and unique to material combination
Achieved by placing shims between plates
Shims designed to be consumed by explosion wave and do not affect weld
Usually ranges between 0.5-2 times the thickness of cladder plate
Cladder must reach critical velocity before impact
Assuring a good weld
Three types of detonation wave welds
Shock wave develops if sonic velocity is greater than 120% of material sonic velocity (type 1)
Detached shock wave results when detonation velocity is between 100% and 120% of material sonic velocity (type 2)
No shock wave is produced if detonation velocity is less than material sonic velocity (type 3)
History
Arnold Holtzman and a team at DuPont in Delaware put a lot of research into developing the process.
Holtzman filed for a US patent in 1962 for explosion welding, received the patent in 1964 and began commercial production of bi-metallic explosion welded clad in 1965.
Detaclad licensed the process and was bought by Dynamic Materials Corporation (DMC).
Other companies have merged with DMC and acquired the current name DMC Groupe SNPE making them a worldwide company.