SMAW

SMAW

SHIELDED METAL ARC WELDING AWS Classification

ARC WELDING

STICK WELDING

FACTS ABOUT SMAW Originated at start of WWI for shipbuilding

SMAW is the least expensive arc welding processes

Is the most widely used welding process in the world

Can be used to weld most common metals and alloys

SMAW COMPONENTS

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1- The Electrode • Consumable… • 2 Part Composition

Core Rod (Metal Filler)Carries welding current &Becomes part of the weld

Flux Coating Produces a shielding gas & helps form slag

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2- The Arc• Turn on the light…An arc

occurs when the electrode comes in contact with the work-piece and completes the circuit

• The electric arc is established in the space between the end of the electrode and the work causing resistance

• The arc reaches temperatures of 10,000°F which melts the electrode and base material

Can you identify the weld joint and position being used?

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3- Weld Puddle• As the core rod, flux

coating, and work pieces heat up and melt, they form a pool of molten material called a weld puddle

• The weld puddle is what a welder watches and manipulates while welding

1/8” E6013 at 125 Amps AC

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4- Shielding Gas

• A shielding gas is formed when the flux melts.

• This protects the weld puddle from the atmosphere preventing contamination during the molten state

The shielding gas protects the molten puddle from the atmosphere while stabilizing the arc

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Shielding Gas4

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5- Solidified Weld Metal• As the molten weld puddle solidifies, it forms a joint

or connection between two pieces of base material• When done properly on steel, it results in a weld

stronger than the surrounding base metal• Bead width = 2.5 to 3 times electrode diameter

3/8”

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6- Slag• Combination of melted flux & base metal impurities • Quickly solidifies to form a shell• Slows the cooling rate of weld• Chip and clean with hammer & brush• If proper technique is used it should come off easy• Never weld over slag!!

ALWAYS SIDE CHIP SLAG, DON’T HIT IT LIKE A HAMMER

Slag You Drag!• Slag Welding Processes

– ALWAYS PULL THE PUDDLE– Shielded Metal Arc Welding (SMAW)– Flux Core Arc Welding (FCAW)

• No-Slag Welding Processes– ALWAYS PUSH THE PUDDLE– Gas Metal Arc Welding (GMAW)– Gas Tungsten Arc Welding (GTAW)– Oxy-Fuel Welding

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SMAW Process

1Travel direction

Electrode

Arc2Weld Puddle 3

Shielding Gas4

Solidified Weld Metal5

Slag6

1Travel direction

Electrode

Arc2Weld Puddle3

Shielding Gas4

Solidified Weld Metal5

Slag6

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Activity

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5

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Let’s review the SMAW process … • 1 = __________

• 2 = __________

• 3 = __________

• 4 = __________

• 5 = __________

• 6 = __________

AWS Electrode Classification

Electrode Selection

• What type of welder do I have, AC or DC?• What am I welding, steel, cast, stainless, etc?• What is the metal condition, dirty or clean?• Is it a root or cover pass?• How strong does it have to be?• What electrodes do I have to chose from?

Electrode Selection

Amperage Chart• Amperage is dependent on electrode

diameter, electrode type, and metal thickness• Reference charts whenever possible.

Amperage Electrode

• Shorthand method will get you in the ballpark for fast freeze electrodes.

Not 100% accurate for all electrodes!

AWS: 1/8” diameter E6013 1/8”= .125”

125 Amps

Electrode Care• Electrodes must be kept dry

– Dampness will introduce hydrogen into the weld causing cracking or brittleness

– Damp electrodes may cause the flux to “blow away” & cause porosity

– Bake questionable electrodes for several hours.

– 6010 & 6011 (fast freeze) are exempt • Our electrodes are stored in a dry oven

Electrodes Care cont.• Burn electrodes down to numbers!• Place stubs in stub box• Put unused electrodes back in oven• Only grab several electrodes at a time• Electrodes are not cheap

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Striking an Arc and Making a Weld

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Striking an Arc • To begin the SMAW Process, you must first

strike an arc. – Scratch start – scratch the electrode on the base

metal like a match– Tap Start – tap the rod against the base metal

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Work Angle

• The work angle is the angle between the electrode and the work as depicted on the left

• Work angles can vary depending on the position the weld is being made in

90°

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Travel Angle

• Also commonly called Lead Angle

• The travel (lead) angle is the angle between the electrode and the plane perpendicular to the weld axis

20-30°

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Arc Length• After striking the arc, maintain a 1/8”

distance between the electrode and the workpiece– Too short: electrode will fuse itself to metal– Too long: spatter, undercut, and porosity

Arc Length = 1/8”

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Travel Speed • Speed at which the electrode moves along the

base material while welding– Too fast: ropey or convex weld – Too slow: wide weld, excessive deposit

The travel speed impacts the shape of the bead.

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Filling the Crater• At the end of the weld, the operator breaks the

arc which creates a ‘crater’• Use a short pause or slight back step at the end

of the weld to fill the crater• Large craters can cause weld cracking

Back stepping is a short move in the opposite direction of weld travel

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Restarting a Bead• Remove electrode from stinger• Scratch electrode until metal can be seen• Scratch in weld line: spatter

1. Strike Arc Here

2. Move Electrode to Crown of Crater

3. Resume Travel

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Troubleshooting Activity

A B C D E F G

On a piece of scratch paper, describe welds A-G.Good, bad, arc length, speed, lead angle, etc.

• A – Good Weld: Proper Current, Speed and Arc Length• B – Current low: Ropey, convex bead appearance• C – Current too High: Excess spatter & burn-through• D – Arc Length too short: Poor wet-in at toes• E – Arc Length too Long: Spatter, undercut and porosity• F – Travel Speed too slow: Wide weld with excess

deposit• G – Travel Speed too high: Ropey and convex bead

Lincoln V350 SMAW Setup

1. Plug ground cable into the (-) terminal2. Plug the whip cable into the (+) terminal3. Turn on the welder4. Select SMAW (CC-Stick Soft) mode

– CC-Stick Crisp is for pipe welding5. Select correct amps6. Set Hot start to 2-3

– (This will make starting the arc easier) 7. Set Arc Control to +4-5

– (high arc control = crisp weld but more spatter)– (low arc control = soft weld with little spatter)