introduction-to-arc-welding processes.ppt

Various arc welding process

1. INTRODUCTION TO ARC INTRODUCTION TO ARC
WELDINGWELDING
(SMAW)(SMAW)

2. Terms & DefinitionsTerms & Definitions
Welding - Joining of two or more Welding - Joining of two or more
pieces of metal together by the fusion pieces of metal together by the fusion
processprocess
NOTE: In arc welding, heat is produced by the NOTE: In arc welding, heat is produced by the
electric arc created.electric arc created.
SMAW - Shielded Metal Arc WeldingSMAW - Shielded Metal Arc Welding
Electrode - Metal rod which conducts Electrode - Metal rod which conducts
a current from the electrode holder to a current from the electrode holder to
the base metalthe base metal
Base Metal - Metal to be weldedBase Metal - Metal to be welded

3. ContinuedContinued
Bead Weld - Made by one pass of Bead Weld - Made by one pass of
the electrodethe electrode
Bevel – Type of edge preparation Bevel – Type of edge preparation
containing an anglecontaining an angle
Butt Joint - Weld located between Butt Joint - Weld located between
the two edges of metal.the two edges of metal.
Crater - Depression at the end of a Crater - Depression at the end of a
weld weld

4. Safety precautions in SMAW Safety precautions in SMAW
weldingwelding
Never look at the arc with the naked eye.Never look at the arc with the naked eye.
Use a welding hood that is in good Use a welding hood that is in good
condition and has a #12 shade.condition and has a #12 shade.
Wear suitable clothing to protect all parts Wear suitable clothing to protect all parts
of the body. (PPE) of the body. (PPE) personal protective personal protective
equipmentequipment
Long sleeved shirtLong sleeved shirt
Leather glovesLeather gloves
Collar buttonedCollar buttoned

5. ContinuedContinued
Cuffs turned downCuffs turned down
High topped shoes or bootsHigh topped shoes or boots
Do not strike an arc or weld until Do not strike an arc or weld until
you are sure those in the vicinity you are sure those in the vicinity
have protective equipment or have protective equipment or
will look in the other direction.will look in the other direction.
(Note) Yell “cover” before striking an arc.(Note) Yell “cover” before striking an arc.

6. ContinuedContinued
Do not weld around combustible Do not weld around combustible
or flammable materials.or flammable materials.
Do not pick up hot metal with Do not pick up hot metal with
the hands.the hands.
(NOTE) Use a pair of pliers(NOTE) Use a pair of pliers
Do not weld in confined places Do not weld in confined places
without ventilationwithout ventilation

7. ContinuedContinued
Always turn off main switch or Always turn off main switch or
disconnect plug when checking over disconnect plug when checking over
a welder.a welder.
Do not leave electrode holder on the Do not leave electrode holder on the
welding table or in contact with welding table or in contact with
grounded metal.grounded metal.
Do not use worn or frayed cables.Do not use worn or frayed cables.

8. ContinuedContinued
Stand on dry footing when welding.Stand on dry footing when welding.
Keep area around welder clean.Keep area around welder clean.
Keep tools and metals in proper Keep tools and metals in proper
location.location.

9. Types of Arc WeldersTypes of Arc Welders
A.C. – (Alternating current) Welder A.C. – (Alternating current) Welder
current alternates direction 120 current alternates direction 120
times per second.times per second.
D.C. – (Direct current) Welder D.C. – (Direct current) Welder
current flows in the same direction.current flows in the same direction.
TIG – (Tungsten Inert Gas) Welder TIG – (Tungsten Inert Gas) Welder
may use either A.C. or D.C. with a may use either A.C. or D.C. with a
non-consumable tungsten electrode non-consumable tungsten electrode
and an inert shielding gas.and an inert shielding gas.

10. ContinuedContinued
MIG – (Metal Inert Gas) May use MIG – (Metal Inert Gas) May use
A.C. or D.C. with a base wire filler A.C. or D.C. with a base wire filler
material that is fed automatically into material that is fed automatically into
weld; also has an inert shielding gas.weld; also has an inert shielding gas.

11. Common SMAW ToolsCommon SMAW Tools
WelderWelder
Electrode HolderElectrode Holder
Ground clampGround clamp
Shield or helmetShield or helmet
GlovesGloves
Chipping hammerChipping hammer
Safety goggles or glassesSafety goggles or glasses
Wire brushWire brush
ElectrodesElectrodes

12. Types of ElectrodesTypes of Electrodes
Mild SteelMild Steel
High Carbon SteelHigh Carbon Steel
Hard SurfacingHard Surfacing
Alloys – special purposeAlloys – special purpose

13. AWS Current
Class CoveringRequirements Position Characteristics
EXX 10 Cellulose DCEP All Deep Penetration,
Sodium With Ripples
EXX 11 Cellulose AC, DCEP All Deep Penetration,
Potassium Flat Decking With Ripples
EXX22 Rutile DCEN, AC Flat, Horiz. FilletDeep Penetration,
Sodium With Ripples
EXX 24 Rutile AC, DCEP, DCENFlat, Horiz. FilletHigh Deposition
50% Iron Shallow Penetration
Powder
EXX 27 Mineral AC,DCEP, DCEN Flat, Horiz. FilletHigh Deposition
50% Iron Shallow Penetration
Powder
Electrode CharacteristicsElectrode Characteristics

14. AWS Current
Class CoveringRequirements Position Characteristics
EXX 12 Rutile DCEN, AC All Mild to Medium Penetration
Sodium
EXX 13 Rutile AC, DCEP, DCEN All Mild Penetration
Sodium
EXX 14 Rutile AC, DCEN All Medium Penetration
30% Iron
Powder
EXX 18Low-Hydrogen DCEP, AC All Medium Penetration
30% Iron
Powder
EXX 28Low-Hydrogen AC, DCEP Flat, Horiz. FilletHigh Deposition
50% Iron
Powder
Electrode Characteristics Electrode Characteristics continuedcontinued

15. Common Sizes of ElectrodesCommon Sizes of Electrodes
1/8”1/8”
5/32”5/32”
Sizes of electrodes range from 1/16” Sizes of electrodes range from 1/16”
to 3/8”.to 3/8”.
Electrode size is determined by the Electrode size is determined by the
diameter of the wire core.diameter of the wire core.

16. E70XX-H4RE70XX-H4R
•ElectrodeElectrode
Tensile in KsiTensile in Ksi
Welding Position:Welding Position:
1 = All Position, 2 = Flat & Horizontal1 = All Position, 2 = Flat & Horizontal
Type of Current and CoatingType of Current and Coating
*Hydrogen:*Hydrogen:
H4 = Less than 4ml/100g weld metal, H8 = Less than 8ml/100g Weld MetalH4 = Less than 4ml/100g weld metal, H8 = Less than 8ml/100g Weld Metal
or H16 = Less than 16ml/100g weld metal or H16 = Less than 16ml/100g weld metal
*Meets Requirements of Absorbed Moisture Test*Meets Requirements of Absorbed Moisture Test
*Optional Designators*Optional Designators
AWS ClassificationAWS Classification

17. Electrode Coating FunctionsElectrode Coating Functions
To Provide Deoxidizers & Scavengers To Provide Deoxidizers & Scavengers
To Produce Shielding GasesTo Produce Shielding Gases
To Produce a Slag CoveringTo Produce a Slag Covering
To Provide Mechanical and Physical To Provide Mechanical and Physical
PropertiesProperties
To Increase Deposit RatesTo Increase Deposit Rates

18. Effects of Raising & Lowering Effects of Raising & Lowering
CurrentCurrent
Raising currentRaising current
Produces more heatProduces more heat
Lowering currentLowering current
Produces less heatProduces less heat
(Note: On thicker metals more heat is (Note: On thicker metals more heat is
necessary in order to get penetration necessary in order to get penetration
of the weld.)of the weld.)

19. Methods of Establishing an ArcMethods of Establishing an Arc
ScratchingScratching
Similar to striking a matchSimilar to striking a match
TappingTapping
Straight down and up Straight down and up

20. Characteristics of Proper Arc Characteristics of Proper Arc
LengthLength
End of electrode is the same distance End of electrode is the same distance
from the base metal as the diameter from the base metal as the diameter
of electrode.of electrode.
1/8” electrode = arc length 1/8”1/8” electrode = arc length 1/8”
Correct arc length makes a steady Correct arc length makes a steady
hum of the welder.hum of the welder.
Correct arc length makes a “frying” Correct arc length makes a “frying”
sound at the arcsound at the arc
Like bacon frying in a panLike bacon frying in a pan

21. Parts of the welding processParts of the welding process
ElectrodeElectrode
Wire coreWire core
Coating (flux)Coating (flux)
ArcArc
Gaseous shieldGaseous shield
WeldWeld
SlagSlag

22. Parts ContinuedParts Continued
Heat linesHeat lines
Base metalBase metal
PenetrationPenetration
CraterCrater
15 – 30 degree angle15 – 30 degree angle
Direction of travelDirection of travel

23. Principles of the SMAW Principles of the SMAW
ProcessProcess

24. Kinds of WeldsKinds of Welds
Fillet Fillet
GrooveGroove
BeadBead

25. Fillet WeldFillet Weld

26. Groove WeldsGroove Welds

27. ContinuedContinued

28. Types of Weld JointsTypes of Weld Joints
Butt JointButt Joint
Lap JointLap Joint
Tee JointTee Joint
Corner JointCorner Joint
Edge JointEdge Joint

29. Square Butt JointSquare Butt Joint

30. Tee JointsTee Joints
A- plain teeA- plain tee
B- single beveledB- single beveled
C- double beveledC- double beveled
D- single JD- single J
E- double JE- double J

31. Lap JointsLap Joints
A- single lap joint, A- single lap joint,
one weld.one weld.
B- single lap joint, B- single lap joint,
two welds.two welds.
C- offset lap joint.C- offset lap joint.

32. Corner JointsCorner Joints

33. Edge JointsEdge Joints

34. Welding PositionsWelding Positions
FlatFlat
1F & 1G1F & 1G
HorizontalHorizontal
2F & 2G2F & 2G
VerticalVertical
3F & 3G3F & 3G
OverheadOverhead
4F & 4G4F & 4G

35. Weld PositionsWeld Positions

36. Reason for Poor WeldsReason for Poor Welds
Machine adjustment too hot or too Machine adjustment too hot or too
coldcold
Electrode size too large or too smallElectrode size too large or too small
Improper movement of electrodeImproper movement of electrode
Improper angle of holding electrodeImproper angle of holding electrode
Improper base metal preparationImproper base metal preparation
Arc length too long or too shortArc length too long or too short