SMAW. Shielded metal arc welding (SMAW) is commonly referred to as stick welding

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1 SMAW EQUIPMENT

2 SMAW Shielded metal arc welding (SMAW) is commonly referred to as stick welding An electric arc between the stick electrode and the base metal creates heat. Heat melts the base metal and the electrode The electrode is covered in a flux coating that melts and protects the molten pool of metal from contaminants such as the oxygen in the air. Machines use both Direct Current (DC) and Alternating Current (AC) for welding.

3 Arc Welding Power Sources Direct Current Sources One end is positive; one end is negative (ground) Alternating Current Sources The positive and negative switch sides while welding. Voltage electrical potential. It is the amount of electricity that can flow. Current is the amount of electricity that is flowing. Measured in AMPS or amperage. Use higher amps for thicker metal.

4 Welding Leads The electrode lead (cable) and holder (stinger) are what the welder holds. The stinger holds the welder s electrode. The ground lead (cable) and clamp connects the circuit from the work piece back to the machine. Electricity cannot flow without the ground attached. These cables increase in size based on current carrying capacity. Large current, large cables Leads must be insulated with no cuts or abrasions in order to protect the operator from shock.

5 Welding Lead/Cable Electrode holder or stinger Ground clamp

6 Electrodes Identified by a specific number - EXXXX Selected by the diameter and the metal they are intended to weld. They conduct electricity from the lead/holder to the part. The flux covering protects the liquid metal pool from contaminants. The flux dries on top of the weld and must be chipped and brushed away after welding.

7 DC Arc Welding One lead is positive; one lead is negative. Polarity the direction of electron flow. DCEN Direct Current Electrode Negative DCEP Direct Current Electrode Positive Your decision on DCEN or DCEP is based on: Weld penetration desired Rate at which the filler is deposited Position of the weld Thickness of the metals Type of base metal

8 DC Arc Welding Advantages DC gives greater penetration Welds in multiple positions Can weld exotic metals nickel, aluminum, copper

9 AC Arc Welding The polarity reverses at 60 Hz which means it reverses its flow120 times per second. Moderate penetration Can use large diameter electrodes to deposit a lot of filler Machines cost less

10 Arc Welding Safety Welding Hazards: Radiation from the arc ultraviolet and infrared rays Flying sparks and spatter Electrical shock Fumes Burns

11 Welding Safety Procedures Wear proper safety equipment- Welding hood with the proper shade of lens Leather gloves Leather or flame retardant jacket/arm guards Close toed shoes Safety glasses Long pants Ear plugs Hat

12 Welding Safety Procedures Make sure your work station is clean and organized Check for anything flammable Inspect your equipment before you use it Get everything situated before you try to weld Before striking an arc, call out cover so others can lower their hoods

13 Welding Preparation Choose your electrode based on your metal and position. Clean your metal THUROUGHLY! Manage your cords. Make sure they re not on anything hot or sharp. Organize your work area hang pliers, hang grinders/sanders, etc

14 Starting Your Weld Strike an Arc Scratching motion Straight down-and-up motion The end of the electrode must first touch the metal briefly then be withdrawn to the correct distance. If the electrode sticks or welds itself to the metal: Grab electrode with free hand and bend back and forth until free If electrode does break free, release stinger from electrode

15 Running a Bead Variables controlled by the welder Arc Length distance of the electrode above the base metal. Distance increases amps Electrode Angle the angle formed between the electrode and your base metal Tipped forward 20 towards the direction of travel Weld speed how quickly you move across the weld. Bead width The widest part of the weld

16 Welding Beads Stringer Beads Forward motion only Width should be 2-3 times the electrode diameter this is controlled by your welding speed Weaving Beads Electrode is moved in short J movements Bead should be no wider than 6X the electrode diameter.

17 Cleaning the Bead When you are done welding a brittle slag coating will be left on the weld. Use a chipping hammer to break up the slag Use a wire brush to remove the slag