2 Student Learning Objectivities: Upon completion of this lesson students will be able to:identify definitions and terminology associated with weldingDemonstrate safe working habits in the welding environmentName the parts and types of welds and weld jointsInterpert SMAW BasicsDiscuss SMAW Equipment Set-UpDemonstrate how to run a uniform welding bead using the “Frosting Bead” lab activity
3 What is welding?Welding is a joining process used in the fabrication and repair of materials – like metals or alloys – through the process of coalescence.Welding uses electricity to generate temperatures as hot at 10,000 degrees F!The heat melts metals into a moletn pool that quickly solidifies into a strong joint.
4 SMAW PrinciplesThe American Welding Society defines SMAW as Shielded Metal Arc WeldingSMAW:Is commonly known as ‘Stick’ welding or manual arc weldingIs the most widely used arc welding process in the worldCan be used to weld most common metals and alloys
5 SMAW Welding CircuitCurrent flows through the electrode cable, to the electrode holder, through the electrode, and across the arcOn the work side of the arc, the current flows through the base material to the work clamp and back to the welding machine
6 SMAW Process Let’s take a little closer look at the SMAW process… 1 2 Travel directionElectrodeArc2Weld Puddle3Shielding Gas4Solidified Weld Metal5Slag6Electrode1Travel directionShielding Gas4Slag63Weld Puddle2Arc5Solidified Weld Metal
7 1- The ElectrodeIs a consumable - it gets melted during the welding processIs composed of two partsCore Rod (Metal Filler)Carries welding currentBecomes part of the weldFlux CoatingProduces a shielding gasCan provide additional fillerForms a slag
8 2- The ArcAn arc occurs when the electrode comes in contact with the work-piece and completes the circuit … like turning on a light!The electric arc is established in the space between the end of the electrode and the workThe arc reaches temperatures of 10,000°F which melts the electrode and base materialCan you identify the weld joint and position being used?
9 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
10 4- Shielding Gas23Shielding Gas4A shielding gas is formed when the flux coating melts.This protects the weld puddle from the atmosphere preventing contamination during the molten stateThe shielding gas protects the molten puddle from the atmosphere while stabilizing the arc
11 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 metal
12 6- SlagSlag is a combination of the flux coating and impurities from the base metal that float to the surface of the weld.Slag quickly solidifies to form a solid coatingThe slag also slows the cooling rate of the weldThe slag can be chipped away and cleaned with a wire brush when hard
14 Striking an ArcTo begin the SMAW Process, you must first strike an arc. This can be done using one of the following techniques:Scratch start – scratch the electrode on the base metal like a matchTap Start – tap the rod against the base metal
16 Travel SpeedThe travel speed is the speed at which the electrode moves along the base material while weldingToo fast of a travel speed results in a ropey or convex weldToo slow of a travel speed results in a wide weld with an excessive metal depositEnd of WeldThe travel speed impacts the shape of the bead.