3 FACTS ABOUT SMAW Originated at start of WWI for shipbuilding SMAW is the least expensive arc welding processesIs the most widely used welding process in the worldCan be used to weld most common metals and alloys
6 1- The Electrode Consumable… 2 Part Composition Core Rod (Metal Filler)Carries welding current &Becomes part of the weldFlux CoatingProduces a shielding gas &helps form slag
7 2- The ArcTurn on the light…An arc occurs when the electrode comes in contact with the work-piece and completes the circuitThe electric arc is established in the space between the end of the electrode and the work causing resistanceThe arc reaches temperatures of 10,000°F which melts the electrode and base materialCan you identify the weld joint and position being used?
8 3- Weld PuddleAs the core rod, flux coating, and work pieces heat up and melt, they form a pool of molten material called a weld puddleThe weld puddle is what a welder watches and manipulates while welding1/8” E6013 at 125 Amps AC
9 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 state23Shielding Gas4The shielding gas protects the molten puddle from the atmosphere while stabilizing the arc
10 5- Solidified Weld Metal As the molten weld puddle solidifies, it forms a joint or connection between two pieces of base materialWhen done properly on steel, it results in a weld stronger than the surrounding base metalBead width = 2.5 to 3 times electrode diameter3/8”
11 6- Slag Combination of melted flux & base metal impurities Quickly solidifies to form a shellSlows the cooling rate of weldChip and clean with hammer & brushIf proper technique is used it should come off easyNever weld over slag!!ALWAYS SIDE CHIP SLAG, DON’T HIT IT LIKE A HAMMER
12 Slag You Drag! Slag Welding Processes No-Slag Welding Processes ALWAYS PULL THE PUDDLEShielded Metal Arc Welding (SMAW)Flux Core Arc Welding (FCAW)No-Slag Welding ProcessesALWAYS PUSH THE PUDDLEGas Metal Arc Welding (GMAW)Gas Tungsten Arc Welding (GTAW)Oxy-Fuel Welding
13 SMAW Process 1 2 3 4 5 6 1 4 6 3 2 5 Travel direction Electrode Arc Weld Puddle3Shielding Gas4Solidified Weld Metal5Slag6Electrode1Travel directionShielding Gas4Slag63Weld Puddle2Arc5Solidified Weld Metal
15 AWS Electrode Classification Explain AWS identification of electrodes
16 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?
18 Amperage ChartAmperage is dependent on electrode diameter, electrode type, and metal thicknessReference charts whenever possible.
19 Not 100% accurate for all electrodes! Amperage ElectrodeShorthand method will get you in the ballpark for fast freeze electrodes.Not 100% accurate for all electrodes!AWS: 1/8” diameter E60131/8”= .125”125 Amps
20 Electrode Care Electrodes must be kept dry Dampness will introduce hydrogen into the weld causing cracking or brittlenessDamp electrodes may cause the flux to “blow away” & cause porosityBake questionable electrodes for several hours.6010 & 6011 (fast freeze) are exemptOur electrodes are stored in a dry oven
21 Electrodes Care cont. Burn electrodes down to numbers! Place stubs in stub boxPut unused electrodes back in ovenOnly grab several electrodes at a timeElectrodes are not cheap
22 Striking an Arc and Making a Weld SECTION OVERVIEW:These slides discuss striking an arc and making a weldTEACHER NOTES:Slides 22-29: When using these slides, teachers may prefer to discuss the importance of the following topics:Striking an arcWork angleTravel angleArc lengthTravel speedFilling a craterRestarting the bead
23 Striking an ArcTo begin the SMAW Process, you must first strike an arc.Scratch start – scratch the electrode on the base metal like a matchTap Start – tap the rod against the base metal
24 Work AngleThe work angle is the angle between the electrode and the work as depicted on the leftWork angles can vary depending on the position the weld is being made in90°
25 Travel Angle Also commonly called Lead Angle The travel (lead) angle is the angle between the electrode and the plane perpendicular to the weld axis20-30°
26 Arc LengthAfter striking the arc, maintain a 1/8” distance between the electrode and the workpieceToo short: electrode will fuse itself to metalToo long: spatter, undercut, and porosityArc Length = 1/8”
27 Travel SpeedSpeed at which the electrode moves along the base material while weldingToo fast: ropey or convex weldToo slow: wide weld, excessive depositThe travel speed impacts the shape of the bead.
28 Filling the CraterAt 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 craterLarge craters can cause weld crackingBack stepping is a short move in the opposite direction of weld travel
29 Restarting a Bead Remove electrode from stinger Scratch electrode until metal can be seenScratch in weld line: spatter1. Strike Arc Here2. Move Electrode to Crown of Crater3. Resume Travel
30 Troubleshooting Activity On a piece of scratch paper, describe welds A-G.Good, bad, arc length, speed, lead angle, etc.ABCDEFGA – Good Weld: Proper Current, Travel Speed and Arc LengthB – Current too low: Ropey, convex bead appearanceC – Current too High: Excess spatter and possible burn-through of base materialsD – Arc Length too short: Poor wet-in at toes, electrode can ‘short’ to base materialE – Arc Length too Long: Excess spatter, undercut and porosityF – Travel Speed too slow: Wide weld with excess metal depositG – Travel Speed too high: Ropey and convex bead
31 A – Good Weld: Proper Current, Speed and Arc Length B – Current low: Ropey, convex bead appearanceC – Current too High: Excess spatter & burn-throughD – Arc Length too short: Poor wet-in at toesE – Arc Length too Long: Spatter, undercut and porosityF – Travel Speed too slow: Wide weld with excess depositG – Travel Speed too high: Ropey and convex bead
32 Lincoln V350 SMAW Setup Plug ground cable into the (-) terminal Plug the whip cable into the (+) terminalTurn on the welderSelect SMAW (CC-Stick Soft) modeCC-Stick Crisp is for pipe weldingSelect correct ampsSet Hot start to 2-3(This will make starting the arc easier)Set Arc Control to +4-5(high arc control = crisp weld but more spatter)(low arc control = soft weld with little spatter)