CONTENTS: PRINCIPLE DEFINITION CHARACTERISTICS PROCESS APPLICATION ADVANTAGES & DISADVANTAGES CONCLUSION
Principles Cold welding is a method for joining nonferrous metals and their alloys without using heat, fillers or fluxes. Round wire sections, dissimilar materials and materials of different sizes can all be welded with BWE's proven cold welding technology. A cold weld is generally stronger than the parent material and has the same electrical characteristics.
Electrical
Solid State Welding
Chemical
Pressure Mechanical
Pressure & Deformation
Cold Weld
DEFINITION OF COLD WELDING Cold welding is a solidstate process in which pressure is used at room temperature to produce coalescence of metals with substantial deformation at the weld. Both butt and lap joints can be cold welded.
Die
Flash
A: Lap both sides indented B: Lap One side indented C: Edge both side indented D: Butt in Tube
E: Draw Weld F: Wire Lap (before and after) G: Mash Cap Joint AWS Welding Handbook H: Butt (before and after)
CHARACTERISTICS OF COLD WELDING
t least one of the metals must be ductile without excessive workhardening.
A
Total absence of applied heating.
Dissimilar metals can be joined.
Surface preparation is important
COLD WELDING PROCESS DESCRIPTION Dies
The parts to be welded are first cleaned. short section of the part is sheared. A
The parts are clamped in a die with some initial extension. forging force is applied to complete welding. A
Workpiece
Workpiece
Before welding
After welding
APPLICATIONS OF COLD WELDING
Cold welded butt joints are used in the manufacturing of aluminum, copper, gold, silver, and platinum wire.
Most commonly, successive reels of wire are joined for continuous drawing to a smaller diameter.
Aluminum
alloys used in cold welding include: 1100, 2319, 3003, all 5000 series, 6061 and 6201.
States of Upset During Butt Upset Cold Weld in Cold Welding Type 1100 Aluminum Wire Courtesy AWS handbook Single
Stages in Multiple Upset Cold Welding AWS Welding Handbook
AWS Welding Handbook
Can Effect Joint Efficiency
Transverse Flow Lines in a Cold Welded Butt Joint Courtesy AWS handbook
Multiple Upset Cold Weld AWS Welding Handbook
K ey
advantages:
Advantages:
1.
Fastest repair capabilities Virtually no deformation Limited dismantling.
Disadvantages While
speed is an advantage to assemblers, it can also be a limitation. The process is so fast that it does not lend itself to deep drawing of material since the material does not have time to stretch. ´
The outer member to be welded must be accelerated at a speed greater than 300 meters per second, says Plum. When a body moving that fast meets another, it will try to displace it. This is what causes the weld. The movable body meets an immovable body. "
"
"
CONCLUSION Transfer of metal and the degree of surface damage during, rubbing are governed by the shear strength of the weld centers formed. The heat developed and the pi tion afforded by oil or other films are here important. For this reason a true picture of the transfer of metal during friction can be obtained only from experiments with the lubricant to be actually used in service in the particular antifriction application.
REFRENCES www.formulasun.org www.yourdictionary.c OM
