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