Introduction to SMAW 252

“Introduction to SMAW” covers the basic theories and practices of shielded metal arc welding (SMAW), as well as common operational procedures. SMAW is a welding process that uses shielding to protect the weld from contamination. SMAW is one of the most common arc welding processes in the world because of its simplicity, versatility, affordability, and suitability for most applications. SMAW requires a range of specialized equipment, specific electrodes, and knowledge of a number of safety precautions.

After taking “Intro to SMAW,” welders will know how to safely handle, prepare, and operate SMAW equipment. They will know also have a basic understanding of how to perform an SMAW weld.

Class Details

Class Name:
Introduction to SMAW 252
Number of Lessons:

Class Outline

  • Shielded Metal Arc Welding
  • Advantages and Disadvantages of SMAW
  • SMAW Equipment
  • The Basics of SMAW: Review
  • Electrical Components
  • Electrical Components: Electricity Transfer
  • Electrode Construction
  • Types of Electrodes
  • Electrode Selection
  • Electrode Selection: Labels
  • Electrode Safety
  • Electrode Review
  • Current
  • Power Sources
  • Amperage
  • Voltage
  • Joint Preparation
  • SMAW Operation
  • SMAW Operation in Action
  • SMAW Preparation and Operation Review


  • Define SMAW.
  • List the advantages and disadvantages of SMAW.
  • Describe SMAW equipment.
  • Describe the electrical components of SMAW.
  • Describe the construction of an electrode.
  • Distinguish between the different types of electrodes.
  • Explain how to select an electrode.
  • Explain how to select an electrode based on the AWS electrode classification system of labeling.
  • Describe how to safely handle and store electrodes.
  • Describe the current requirements for SMAW applications.
  • Describe the power sources required for SMAW applications.
  • Describe the amperage requirements of SMAW.
  • Describe the voltage requirements of SMAW.
  • Explain how to prepare joints for SMAW.
  • Describe the different steps of SMAW operation.

Job Roles



Vocabulary Term Definition
alloys A metal consisting of a mixture of two or more materials. Stainless steel, for example, is an alloy of iron, carbon, and chromium.
alternating current AC. A current that regularly reverses the direction of its flow. In SMAW, it is preferable for power sources to generate both alternating current and direct current to fit all applications.
alternators A device that converts mechanical energy into AC energy. An alternator can provide electrical energy to a power source.
American Welding Society AWS. The non-profit organization that regulates the industrial standards for welding. The American Welding Society also promotes the welding industry in the United States.
amperages The strength of electrical current flowing in a circuit, which is measured in amperes or amps. Amperage in SMAW ranges between 10 to 500 amps.
arc The area in which electricity transfers from the electrode to the workpiece. The heat generated by the arc melts the base metals and filler metal during SMAW.
arc blow A condition where the arc does not follow its intended path and results from the interaction of an electric current and the magnetic field that the current induces. Arc blow can cause excessive spatter, incomplete fusion, and porosity.
arc length The distance the arc stretches from the electrode to the workpiece. Longer arc lengths require an increased level of voltage.
arc voltage The amount of voltage present between the electrode and the workpiece. For SMAW, arc voltage ranges from 14 to 45 volts.
AWS American Welding Society. The non-profit organization that regulates the industrial standards for welding. AWS also promotes the welding industry in the United States.
base metals Metals that are welded together to form a joint. In SMAW, the welder guides the electrode along the seam of the base metals to make a weld.
beveled edge The edge of an object that is not situated perpendicularly to the face of the workpiece. A beveled edge may be created by the welder in order to provide easier access to the weld when working with thicker materials.
calcium A nonmetallic material that is often present in the powdered coating of a SMAW electrode. Calcium floats to the top of the molten weld pool and forms slag.
carbon A common nonmetallic element found in all types of steel. Carbon is added to the filler metal in an SMAW electrode to help strengthen the joint.
chipping hammer A tool used to scrape slag from a cooled weld bead. The chipping hammer is also known as a scaling hammer.
circuit A controlled path for electricity. Like all arc welding processes, SMAW requires a closed electrical circuit in which electricity can easily flow.
complete penetration A weld that extends completely through the thickness of the materials being joined. If complete penetration is required through one side of a joint, base metals may require weld backing.
conductor A material that allows electricity to flow easily. An SMAW electrode consists of a conductor coated in shielding materials.
constant current A current that varies only slightly during welding. SMAW applications require constant current.
consumable electrode An electrode that conducts electricity to the arc but also melts into the weld as a filler metal. SMAW consumable electrodes also provide shielding that protects the arc and weld pool.
cracking Fractures that develop in the weld after solidification is complete. Welds with high hardness are prone to cracking.
crater An undesirable depression in the weld bead. A crater can cause cracking if it is not properly filled.
current The flow of electricity through a circuit. Current, also known as amperage, is measured in amperes, or amps, and controls the heat of the arc.
DC positive DC+. Direct current with reverse polarity. DC+ may also be expressed as DCEP.
direct current DC. A current that flows in one continuous direction. In SMAW, it is preferable for power sources to generate both alternating current and direct current to fit all applications.
discontinuities An irregularity in the specified and expected composition of a weld, which may or may not be considered a defect. During SMAW, discontinuities are sometimes caused when a welder must stop and start welding to change the electrode.
downhill-position welding The welding position used to weld from top of a joint and progressing downard. Downhill-position welding is done effectively in SMAW when using fill-freeze electrodes.
electrode A device in an electrical circuit that conducts electricity. In SMAW, the electrode acts as filler metal.
electrode cable The path used in welding to conduct electricity from the power source to the electrode. Electrode cables and work cables connect to the power source, the workpiece, and the electrode, which provides a closed electrical circuit.
electrode holder The insulated handle that clamps on to the electrode. The electrode holder is connected to the power source during welding to control the arc.
electrode orientation The position in which the welder manipulates the electrode to create a weld bead. Electrode orientation refers to the work angle and travel angle.
electromagnetic induction The process in which current is induced in a magnetic field using a current-carrying coil. An AC generator produces a current through electromagnetic induction.
engine-driven Welding power sources that convert mechanical energy intro electrical energy. Energy is obtained from a gas or diesel engine or an electrical motor.
fast-fill electrodes An SMAW electrode that fills a joint quickly due to the addition of iron powder in the flux. Fast-fill electrodes melt quickly and are ideal for large workpieces.
fast-freeze electrodes An SMAW electrode that solidifies quickly. Fast-freeze electrodes are ideal for overhead welding and correcting poor fit-up and gaps.
ferrous A metal that contains iron. Ferrous metals are the most common type of welded materials.
filler metal A type of metal that has properties similar to those of the base metal and is added to the weld. Filler metal often adds to the strength and mass of the welded joint.
fill-freeze electrodes An SMAW electrode that has both fast-fill and fast-freeze characteristics. Fill-freeze electrodes both fill a joint and solidify quickly.
fit-up The way mating parts fit together. Proper fit-up is indicated when parts fit together without extra space or gaps.
flat-position welding The welding position used to weld from the upper side of the joint. In flat-position welding, the face of the weld is horizontal.
flux A non-metallic material used to protect the weld pool and cooling metal from atmospheric contamination in some welding processes. SMAW uses electrodes that have flux-coated cores.
gaps The extra, undesirable space between mating parts. Gaps can be corrected by SMAW with a fast-freeze electrode.
generators A device that converts mechanical energy to electrical energy, producing DC. Magnetic induction causes this conversion.
horizontal-position welding A common welding position used for fillet and groove welds. In horizontal-position welding, fillet welds are welded on the upper side of a horizontal surface and against a vertical surface, while groove welds require the weld axis to lie horizontally on a plane with the weld face in the vertical plane.
incomplete fusion A weld discontinuity in which fusion did not properly occur between weld metal and base metal or adjoining weld beads. When there is incomplete fusion, the metals have not been effectively welded together, and the weld is defective.
inverters An energy-efficient welding machine that runs in constant current and constant voltage modes with variable frequencies, amplitudes, and AC/DC output. Inverters provide feedback on the welding parameters.
joint preparation A variety of processes that prepare base metals for welding. Joint preparation often includes preheating, cutting, or other processes.
low-hydrogen electrodes An SMAW electrode that is used to weld metals that are susceptible to cracking.
manganese A hard, brittle, gray-white metal often added to electrodes. Manganese acts as a deoxidizer and increases strength and hardness in the weld.
manual welding An arc welding process that uses a flux-coated electrode. Manual welding is also referred to as shielded metal arc welding, SMAW, or stick welding.
mechanical energy A combination of kinetic and potential energy resulting from the force of gravity or the movement or release of a machine component, such as a spring, clamp, or wheel. Mechanical energy can be converted to electrical energy by a generator.
mechanical properties A property that determine a material's ability to compress, stretch, bend, scratch, dent, or break. The mechanical properties of a material describe the way a material responds to forces.
multi-process machines Power sources that can perform all functions of different power sources. Multi-process machines can successfully complete a wide variety of of welding processes.
nitrogen A colorless, odorless, tasteless gas that naturally makes up 78% of breathable air. Nitrogen can ruin a weld bead, so electrodes often contain elements to de-nitrify the molten metal.
nonferrous A metal that does not contain iron as a main ingredient. Common nonferrous metals include aluminum, titanium, copper, and nickel.
out-of-position Welds performed by a welder that are not made in a classified or categorized position. Out-of-position welds are often done with electrodes that have smaller diameters to prevent spillage.
overhead-position welding Welding that is performed from the underside of a joint. Overhead-position welding requires extra safety precautions.
oxygen A colorless, odorless, tasteless gas that naturally exists in the atmosphere. A small amount of oxygen is sometimes used for shielding, but too much oxygen causes cracking, porosity, and rusting in the welded metals.
personal protective equipment PPE. Any clothing or device worn to minimize exposure to hazards and prevent injury. Personal protective equipment for welding usually includes a face shield, jacket, safety glasses, and gloves.
polarity Having two oppositely charged poles, one positive and one negative. Polarity determines the direction in which current flows.
porosity A discontinuity characterized by the appearance of tiny voids or bubbles on a weld bead, resulting from trapped gases in a material. Excessive porosity can weaken a weld.
power source A device that generates electricity. Arc welding power sources can be plugged into wall outlets or use a device, such as a motor or generator, to create electricity.
rectifier A device used in an electrical circuit that converts AC into DC. A rectifier is used with a transformer.
scaling hammer A tool used to scrape slag from a cooled weld bead. The scaling hammer is also known as a chipping hammer.
scratching A method of striking the arc by quickly moving an electrode across the surface of a workpiece at an angle. The scratching method closely resembles striking a match.
seam The place where metal parts meet or overlap. The welder guides the electrode along the seam to fuse metals together.
shielded metal arc welding SMAW. An arc welding process that uses a flux-coated electrode. Shielded metal arc welding is also referred to as stick welding or manual welding.
shielding A gas or type of flux that protects the weld pool and arc from atmospheric contamination. Shielding is provided by the material coating the electrode in SMAW processes.
short circuit An unwanted electrical connection between a negative and positive source or an interruption in the flow of electricity. Short circuits can damage equipment and can cause sparks or fire.
silicon A nonmetallic material that is often present in arc welding electrodes. Silicon acts as a deoxidizer.
slag Cooled flux that forms on top of the weld bead. Slag protects cooling metal and is then chipped off.
SMAW Shielded metal arc welding. An arc welding process that uses a flux-coated electrode. SMAW is also referred to as stick welding or manual welding.
spatter Liquid metal droplets expelled from the welding process. Spatter can leave undesirable dots of metal on the surface of a workpiece.
spring-loaded clamp A device that holds objects together by applying inward pressure. The resistance of the clamps is controlled by a spring.
square groove joint A type of weld that consists of an opening between two square part surfaces, which provides space to contain weld metal. In SMAW, a square groove joint requires the welder to square off the edges of the base metals to effectively make the weld.
stick welding An arc welding process that uses a flux-coated electrode. Stick welding is also referred to as shielded metal arc welding, SMAW, or manual welding.
tapping A method of striking the arc in which the welder quickly moves the electrode downward to the base metal in a vertical direction. Tapping is one method used to start an arc in SMAW.
tensile strength A material's ability to resist forces that attempt to pull it apart or stretch it. Electrodes must create welds that at least meet the minimum tensile strength required to prevent the finished part from deforming or failing.
T-joint A joint formed when the edge of one part is welded to the surface of another part in the shape of a T. T-joints are a very comment joint type.
transformers A device that transfers electrical energy from one circuit to another, without changing the frequency, using electromagnetic induction. A transformer is most often used to change voltage.
undercut An unintended void left in a finished weld. Different amounts of undercut are acceptable depending on the code being followed and the welding application.
vertical-position welding The welding position in which welding is done on a vertical surface, moving up or down. Vertical-position welding is more difficult than flat- or horizontal-position welding.
voltage A measure of the electrical pressure or potential. Voltage is measured in volts.
volts A unit of measurement for electromagnetic force or pressure. The voltage between the electrode and workpiece in SMAW usually ranges from 14 to 45 volts.
weld backing A strip of metal located on the side opposite of the weld that provides a surface for depositing the first layer of metal and prevents molten metal from escaping through the joint. Weld backing can also be used to protect the back of the weld from atmospheric contamination.
weld bead The end product of a joint that has been welded. Weld beads are formed using a variety of different techniques.
weld penetration The depth to which the arc heat melts the joint below the surface of the base metals. The amount of amperage directly affects weld penetration.
weld pool The small area of molten metal that forms during welding. The cooled weld pool forms the permanent joint.
weld root The point at which the back of a weld intersects the surfaces of the base metal. Defects in welds can occur at the weld root.
welder The person who performs welding. SMAW is the most common arc welding process that welders use.
welding helmets A protective eye and face shield worn during welding. Welding helmets protect the welder from the arc's harmful rays and intense bright light.
welding parameters The specifications or properties that are related to a specific power source. Welding parameters include current, arc, voltage, travel speed, and electrode type and size.
welding position The position in which the welder performs a weld. Welding positions include overhead-, vertical-, flat-, and horizontal-position welding.
wire brush A tool with wire filament used to remove burrs, scale, and flash. Using a wire brush to clean a metal is a method of joint preparation.
work cable A component that connects to the work cable to the workpiece. The work clamp provides ground for the SMAW circuit.
work cable The path used in welding to conduct electricity from the power source to the work clamp. Work cables and electrode cables connect to the power source, the workpiece, and the electrode, providing a closed electrical circuit.
workpiece The object or material being welded. Workpieces can be made out of a variety of materials when SMAW is used.
yield strength A metal's ability to resist gradual progressive force without permanent deformation. In SMAW applications, AC offers less yield strength in the final weld than DC.