Explosive welding is a solid-state process that joins dissimilar metals through high-velocity impact using controlled explosions. It produces strong welds without heat effects or microstructural changes common in other welding methods. The explosive material is placed between the metals to be joined and detonated, driving one metal into the other at velocities over 4500 m/s to form a metallurgical bond. Explosive welding can join materials like aluminum to steel that are difficult to weld through other methods. It has applications in industries like petroleum refining, shipbuilding, and aerospace for cladding, sealing, and repairing parts.

1. Explosive Welding

2. Introduction
Principle of Explosion Welding
 Salient Features of Explosion Welding
 Explosives Materials
 Advantages & Disadvantages
 Applications
Contents

3.  Explosion welding is a solid-state
process that produces a high velocity
interaction of dissimilar metals by a
controlled detonation.
Introduction
 This eliminates the
problems of heat effects
& micro-structural
changes (as in fusion
welding).
 Oxides found on material surfaces must be removed
by effacement or dispersion
Fig. Explosive Welding

4. 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.
 Waves are generated so due to mechanical
bonding joining takes place.
 A single detonation cap can be used to ignite
the explosive.

5. 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

6. Salient Features
 The high velocities are promoted by carefully
detonated explosives.
 The process can be done in vacuum to reduce
sound & blast.
 Typical impact pressure are millions of psi.
 Well suited to metals that are prone to brittle
joints when heat welded such as,
• Al on steel
• Ti on steel

7.  Typical explosive forms
• Plastic flexible sheer
• Cord
• Pressed shapes
• Cast shapes
• Powder/granular
 Detonation velocity is a function of
• Explosive type
• Composition of explosive
• Thickness of explosive layer

8. 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)

9. Explosive material
 High velocity (4572-7620 m/s)
• Trinitrotoluene (TNT)
• Cyclotrimethylenetrinitramine (RDX)
• Pentaerythritol Tetranitrate (PETN)
• Datasheet
• Primacord
 Mid-low velocity (1524-4572 m/s)
• Ammonium nitrate
• Ammonium perchlorate
• Amatol
• Nitroguonidine
• Dynamites
• Diluted PETN

10. Advantages of Explosion Welding
• Very large work pieces can be welded.
• (Al + Steel) materials can be welded.
• Can bond many dissimilar, normally unweldable
metals.
• Material melting temperatures and coefficients of
thermal expansion differences do not affect the final
product.
• Process is compact, portable, and easy to maintain.

11. • Welding can be achieved quickly over large areas.
• No need for surface penetration.
• Backer plate has no size limits.
• Inexpensive.
• The strength of the weld joint is equal to or greater
than the strength of the weaker of two metals joined.
• No heat-affected zone (HAZ).

12. Disadvantages of Explosion Welding
• Metals must have high enough impact resistance and
ductility
• The geometries welded must be simple-flat,
cylindrical, conical
• The cladding plate can’t be too large
• Noise & blast can require worker protection, vacuum
chambers, buried in sand/water.

13. Applications
• Cladding of base metals with thinner alloys e.g.
cladding of Ti with mild steel.
• Seam and lap welds.
• Reinforcing aerospace materials with dissimilar metal
ribs.
• Heat exchangers.
• Tubular transition joints.
• Used as a repair tool for repairing leaking tube-to-
tube sheet joints.
• Spot welding.
• Flat plates.
• Joining of pipes in socket joints.

14. Common industries that use Explosion Welding
• Petroleum Refining
• Chemical Processing
• Hydrometallurgy
• Aluminum Smelting
• Shipbuilding
• Electrochemical
• Oil & Gas
• Power Generation
• Cryogenic Processing
• Pulp & Paper
• Air conditioning &
Chillers
• Metal Production

15. Examples

16. Examples
3” Diameter AI/SS Ring Copper/Stainless 12” UHV Assembly