Non-Arc Welding Processes 1998/1998/MJ1/MatJoin4/1 Non Arc Welding Processes Resistance Weld High...
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Transcript of Non-Arc Welding Processes 1998/1998/MJ1/MatJoin4/1 Non Arc Welding Processes Resistance Weld High...
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/1
Non Arc Welding ProcessesResistance WeldHigh Energy DensityFriction WeldingBrazing & SolderingPlastics Joining
Lesson ObjectivesWhen you finish this lesson you will understand:• Resistance Weldability and Various Resistance Welding Processes• Oxy-fuel welding and cutting principles• Solid state welding processes and comparisons between them• Advantages and disadvantages of each process
Learning Activities1. Read Handbook
pp 16-302. Look Up
Keywords3. View Slides; 4. Read Notes, 5. Listen to lecture6. View Video7. Do on-line
workbook8. Do Homework
Keywords:Resistance Spot Welding, Seam Welding, Spot Weldability Lobe, Oxy-Acetylene Torch, Friction Welding, Diffusion Welding, Ultrasonic Welding, Explosive Welding
Non-Arc Welding Processes (Part 1)
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/3
Non-Arc Welding Processes
Resistive heating, chemical reactions, focused light and electrons, sound waves, and friction can also be used to join materials
Resistance welding Oxy-Fuel Welding Friction welding (&Solid State) Laser and electron beam welding Brazing and soldering Plastics joining Adhesive bonding
Introduction
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/4
Resistance Welding
The resistance of metal to the localized flow of current produces heat
Process variables Current Time Force
Spot and seam welding
Spot welding
Resistance Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/5
electrode
electrode
Spot Weld
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/6
Electrodes
Electrode tips wear during service, causing nugget size to decrease
Zinc-coating on steel alloys with copper electrodes to form brass
Copper base materials, divided into classes
Truncated cone Dome Pointed
Resistance Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/7
Operating Window - Lobe Curve
Current (1000’s of amperes)
Tim
e (c
ycle
s o
f cu
rren
t)
ExpulsionNuggettoo small
Acceptable nugget size
Constant electrodeforce
Resistance Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/8
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/9
Roll spot weld Overlapping seam weld Continuous seam weld
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/10
Resistance Welding Advantages
• High speed, < 0.1 seconds in automotive spot welds
• Excellent for sheet metal applications, < ¼-inch• No filler metal
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/11
Process Disadvantages and Limitations
Higher equipment costs than arc welding
Power line demands Nondestructive testing Low tensile and fatigue
strength Not portable Electrode wear Lap joint requires
additional metal
Resistance Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/12
Link to the “Resistance Welding Videos from the Video Page on the
WE300 Webpage
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/13
Turn to the person sitting next to you and discuss (1 min.):• If the Lobe Curve represents the welding parameter combinations which produce good welds, why do so many of the automotive spot welds have expulsion?
Turn to the person sitting next to you and discuss (1 min.):• When spot welds are place too close to one another, some of the current from the second weld shunts thru the first. Why then can overlap seam welds work when the welds are so close that they overlap?
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/14
Non-Arc Welding Processes
Resistive heating, chemical reactions, focused light and electrons, sound waves, and friction can also be used to join materials
Resistance welding Oxy-Fuel Welding Friction welding (&Solid State) Laser and electron beam welding Brazing and soldering Plastics joining Adhesive bonding
Introduction
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/15
4CO + 2H2 + 3O2 4CO2 + 2H2O
2C2H2 + 2O2 4CO + 2H2 ( Oxygen from torch)
(Oxygen from Air)
Linnert, Welding Metallurgy, AWS, 1994
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/16
Thermite Welding
Liquid
Base Metal
PowerFe2O3 + 2Al > 2Fe + Al2O3 + heat
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/17
Turn to the person sitting next to you and discuss (1 min.):• The oxy-fuel and that thermit welding are both chemical burning reactions. In the first oxygen is supplied by oxygen gas, in the thermit welding, it is supplied by the iron oxide. Why does this aluminum “burning” in the thermit welding work?
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/18
Non-Arc Welding Processes
Resistive heating, chemical reactions, focused light and electrons, sound waves, and friction can also be used to join materials
Resistance welding Oxy-Fuel Welding Friction welding (&Solid State) Laser and electron beam welding Brazing and soldering Plastics joining Adhesive bonding
Introduction
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/19
Solid-State Welding
Processes that produce a weld through the application of pressure at a temperature below the melting temperature of the base material; no filler metal is used
Friction welding Diffusion welding Ultrasonic welding Explosion welding
0.1.1.2.2.T9.95.12
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/20
Friction Welding (FRW)
0.1.1.2.2.T10.95.12
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/21
Friction Welding - Advantages
For correct part geometry, friction welding is faster than most other processes
Can join dissimilar materials together
Copper to steel or aluminum
Easily automated for high volume production
Can join plastics
Friction Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/22
Limitations of Friction Welding
Start-up cost is high Parts must be able
to rotate about an axis of symmetry
Free machining alloys are difficult to weld
Non-forgeable materials cannot be friction welded
Friction Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/23
1st stage deformation forming interfacial
boundary. 2nd stage
Grain boundary migration and pore elimination.
3rd stage Volume diffusion and pore
elimination.
asperities come into contact.
2nd stage grainboundary migrationand pore elimination
1st stage deformationand interfacial boundary formation
3rd stage volumediffusion poreelimination
Diffusion Welding Working Principles
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/24
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/25
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/26
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/27
AWS Welding Handbook
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/28
Ultrasonic Welding
Advantages Fast Can spot or seam weld
Limitations Equipment complex, many
variables Only use on small parts
More on this below for plastics
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/29
Welding arrangement consists of three components -
Base component Prime component Explosive.
Base component remains stationary, supported by anvil.
primecomponent
Basecomponent
Explosive
Component arrangementfor explosion welding
Detonator
Principles of Explosion Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/30
Prime component is placed either parallel or at an angle to the base.
Explosive is distributed over top surface of prime component.
Upon detonation, prime component collides with base component to complete welding. Action between components
during explosion welding.
Detonation
Primecomponent
JetBase
component
Weld
Principles of Explosion Welding
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/31
Linnert, Welding Metallurgy, AWS, 1994
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/32
Turn to the person sitting next to you and discuss (1 min.):• In friction welding, the outer part of the bar is moving faster and will therefore have more heating than the exact center of the bar. What might you do to “even out” the heating across the entire interface?
Non-Arc Welding Processes
1998/1998/MJ1/MatJoin4/33
Do Special Project Homework on Solid State Welding