welding lecture 4 fusion (liquid) state welding processes ( resistance welding)

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05/06/22 Prof.Dr.Adel M.abdelmabo ud 1 Fusion welding 1-Arc welding Shielded Metal Arc welding (SMAW) (Stick welding) Gas-Metal Arc welding (MIG)( GMAW) Flux-Core Arc welding (FCAW) Submerged Arc welding (SAW) Electro Slag welding (ESW ) Gas-Tungsten Arc welding (TIG) (GTAW) Plasma Arc welding (PAW) Consumable electrode Non consumable electrode

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Page 1: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 1

Fusion welding1-Arc welding• Shielded Metal Arc welding (SMAW)(Stick welding)

• Gas-Metal Arc welding (MIG)(GMAW)• Flux-Core Arc welding (FCAW)• Submerged Arc welding (SAW)• Electro Slag welding (ESW )• Gas-Tungsten Arc welding (TIG) (GTAW)• Plasma Arc welding (PAW)

Consumable electrode

Non consumable electrode

Page 2: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 2

Fusion Welding Processes(Liquid State welding)

1. Arc Welding

2. Oxyfuel Gas Welding

3. Resistance Welding (RW)

Page 3: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 3

..\ فيدو الباحة لحام\Resistance Welding\1- resistance welding 3 types.avi

..\ فيدو الباحة Resistance\لحامWelding\8-Resistance Spot

Welding - How It Works عملى.flv

Page 4: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 4

Resistance Welding (RW)

A group of fusion welding processes that use a combination of heat and pressure to accomplish coalescence

• Heat generated by electrical resistance to current flow at junction to be welded

• Principal RW process is resistance spot welding (RSW)

Page 5: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 5

Resistance Welding (RW)

• RW components are:workpart to be welded, two opposing electrodes ,a means of applying to squeeze the parts between the electrodes, and AC power supply.

• How is the spot welds - animation.

Page 6: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 6

Page 7: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 7

Power source in Resistance Welding

• . The amount of heat from the contact resistance at the contact between two materials can be expressed by:

H = R. I 2 . t• Where:

H = Heat generated (Joule) R = electric resistance (Ohm) I = electric current A (5000-2000) although voltage operations is very low (10 V) t = time (S)

• Duration time is short (0.1 to 0.4 )S

Page 8: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 8

Resistance Spot Welding (RSW)

Resistance welding process in which fusion of faying surfaces of a lap joint is achieved at one

location by opposing electrodes • Used to join sheet metal parts using a series of

spot welds • Widely used in mass production of

automobiles, appliances, metal furniture, and other products made of sheet metal

– Typical car body has ~ 10,000 spot welds – Annual production of automobiles in the

world is measured in tens of millions of units

Page 9: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 9

• The reason why such current in RW is because:

1. Square term in Equation ..amplifies the effect of current

2. The resistance is very low 0.0001 ohm• Resistance in the welding circuit is the

sum of1. Resistance of the electrodes2. Resistances of the workparts3. Contact resistances between electrodes and

workparts.4. Contact resistance of fly surfaces

Page 10: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 10

Examples31.2

Page 11: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 11

• Advantages: 1) The machine requires only a short time

which effect of welding temperature (rapid cooling of the weld) leads to a fine grain structure of weld metal which gives minimum stress and strain

2) No filler metal is required .3) High production rates are possible4) Operator skill level is lower than the required for arc

welding5) Good repeatability and reliability.• Drawbacks: 1) Equipment cost is high2) Requires large machinery and stronger construction

inputs 3) Types of joints that can be welded are limited to lap joint

for most RW processes

Page 12: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 12

Advantages / Drawbacks of RW

Advantages:• No filler metal required• High production rates possible• Lends itself to mechanization and automation• Lower operator skill level than for arc welding• Good repeatability and reliability

Disadvantages:• High initial equipment cost• Limited to lap joints for most RW processes

Page 13: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 13

Resistance welding

Spot welding Seam welding Projection welding

Page 14: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 14

1-Resistance Spot Welding (RSW)

Resistance spot welding process in which fusion of faying surfaces of a lap joint is achieved at one location by opposing electrodes

• Used to join sheet metal parts using a series of spot welds

• Widely used in mass production of automobiles, appliances, metal furniture, and other products made of sheet metal – Typical car body has ~ 10,000 spot welds – Annual production of automobiles in the

world is measured in tens of millions of units

Page 15: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 15

Electrode materials

• Materials used for RSW electrodes consist of two groups:

1. Copper based alloys.

2. Refractory metal compositions such as copper and tungsten combinations.

Page 16: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 16

(a) Spot welding cycle, (b) plot of squeezing force & current in cycle (1) parts inserted between electrodes, (2) electrodes close, force applied, (3) current on, (4) current off, (5) electrodes opened.

Spot Welding Cycle

Page 17: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 17

Components in Resistance of spot welding

• Parts to be welded (usually sheet metal)

• Two opposing electrodes

• Means of applying pressure to squeeze parts between electrodes

• Power supply from which a controlled current can be applied for a specified time duration

Page 18: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 18

Page 19: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 19

Spot Welding Examples

Page 20: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 20

Page 21: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 21

..\ فيدو الباحة Resistance\لحامWelding\Weld Procedures Utube Welding Videos - Spot Welding

with Car-O-Liner Welder.flv

..\ فيدو الباحة Resistance\لحامWelding\3- Spot Welding.flv

Page 22: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 22

2- Resistance Seam welding (RSEW)

Uses rotating wheel electrodes to produce a series of overlapping spot welds along lap joint

• Can produce air‑tight joints

• Applications: – Gasoline tanks

– Automobile mufflers

– Various other sheet metal containers

Page 23: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 23

Resistance seam welding (RSEW).

Resistance Seam Welding

Page 24: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 24

..\ فيدو الباحة Resistance\لحامWelding\5-Seam welding

machine.flv

..\ فيدو الباحة Resistance\لحامWelding\7-fig 11-5 eam.swf

Page 25: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 25

Different types of seam resistance welding and applications b-Continuous weld seam C-Continuous weld seam d- Gasoline seam welding

Page 26: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 26

3-Resistance Projection Welding (RPW)

A resistance welding process in which coalescence occurs at one or more small contact points on parts

• Contact points determined by design of parts to be joined– May consist of projections, embossments, or

localized intersections of parts

Page 27: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 27

Resistance projection welding (RPW): (1) start of operation, contact between parts is at projections; (2) when current is applied, weld nuggets similar to spot welding are formed at the projections.

Resistance Projection Welding

Page 28: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 28

Sketch of projection welding

Page 29: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 29

a-Sketch of projection weldingb-welded bracketc,d- projection welding of nuts and threaded bosses and stude- projection welding of grills

Page 30: Welding Lecture 4 Fusion (Liquid) State Welding Processes ( Resistance Welding)

04/11/23 Prof.Dr.Adel M.abdelmaboud 30

..\ فيدو الباحة Resistance\لحامWelding\6- Projection Resistance

Welding Video.flv..\ فيدو الباحة -Resistance Welding\9\لحامWeld Procedures Utube Welding Videos

- ARO Technologies - Projection Welding.flv

..\ فيدو الباحة Resistance Welding\10-Weld\لحامProcedures Utube Welding Videos - Projection

Welding.mp4