What Is Arc Welding? 110

This class introduces the advantages of arc welding as a joining process and explains the fundamentals of arc welding.


Class Name:
What Is Arc Welding? 110
This class introduces the advantages of arc welding as a joining process and explains the fundamentals of arc welding.
Number of Lessons:
Additional Language:
Spanish, Chinese

Class Outline

  • Objectives
  • What Is Welding?
  • Types of Joining Processes
  • Types of Metals
  • Heat Control
  • Fusion Welding
  • What Is Arc Welding?
  • What Is Electricity?
  • Voltage, Current, and Resistance
  • The Path of Electricity
  • The Arc Welding Process
  • Electrodes
  • Arc Shielding
  • Types of Arc Welding Processes
  • Arc Welding Equipment
  • Advantages of Welding
  • Arc Welding Safety
  • Summary


  • Define welding.
  • Explain characteristics that set welding apart from other joining processes.
  • Identify common base metals used for welding.
  • Explain the importance of heat control in welding.
  • Define fusion welding.
  • Define arc welding.
  • Describe the properties of electricity.
  • Identify the variables used to measure electricity.
  • Describe the path of electricity in welding.
  • Describe the arc welding process.
  • Identify the major types of electrodes.
  • Explain the importance of shielding.
  • Identify common arc welding processes.
  • Identify the equipment needed for arc welding.
  • Describe the advantages of welding.
  • Explain the importance of arc welding safety.


  • MSSC Maintenance Awareness
  • AWS SENSE Level 1


Vocabulary Term Definition
adhesive bonding A process that binds materials together using a non-metallic material. Paste, glue, and tape are examples of common adhesives.
aluminum A non-ferrous, silvery-white metal that is soft and light. Aluminum is one of the most difficult metals to weld.
American Welding Society The non-profit society that regulates the industrial standards for welding.
arc The area in which electricity jumps from the electrode to the workpiece. The heat generated by the arc melts the base metals.
arc length The distance that the electricity must travel from the tip of the electrode to the weld puddle.
arc welding A fusion welding process that uses electricity to generate the heat needed to melt the base metals.
atom The smallest distinguishable unit of a material that maintains the same characteristics.
autogenous weld A welding process that does not require a filler metal. Sometimes the joint created by an autogenous weld cannot be detected.
base metal One of the two or more metals to be welded together to form a joint.
bead The end product of a joint that has been welded.
circuit A controlled path for electricity. During welding, the welder, work and electrode cables, electrode, and workpiece form a complete circuit.
conductor A material that allows for the flow of electricity. For a successful arc weld, electrodes and base metals must be good conductors.
consumable electrode An electrode that conducts electricity to the arc but also melts into the weld as a filler metal.
copper A reddish metal that is very ductile, thermally and electrically conductive, and corrosive resistant. Copper can be welded using limited methods.
current The flow of electricity, measured in amperes or amps. Arc welding requires a continous flow of electricity to maintain the arc.
electricity The energy created by the movement of electrons. Electrical energy can be converted into light, heat, or motion.
electrode A device that conducts electricity. In welding, the electrode also can act as the filler metal.
electrode cable The path used in welding to conduct electricity from welder to the electrode. In welding, the cables are connected to the welder, the workpiece, and electrode, providing a closed electrical circuit.
electrode holder The insulated handle that clamps onto the electrode. The welder holds this during welding to control the arc.
electron A negatively charged particle that orbits the nucleus of an atom. Electrons flow between atoms in electrical conductivity.
ferrous metal A metal that contains iron. Ferrous metals are the most common type of welded metal.
filler metal A type of metal sometimes added to the joint in fusion welding. Filler metal adds to the strength and mass of the welded joint.
flux A non-metallic material used to protect the weld puddle and solid metal from atmospheric contamination.
flux-cored arc welding An arc welding process that uses a continuously fed consumable electrode that contains flux at its core. It is also referred to as FCAW.
fusion welding A welding process that melts the base metals at the joint. Upon cooling, the welded joint is often stronger than the base metals.
gas metal arc welding An arc welding process in which the bare wire electrode and inert shielding gas are fed to the weld through a welding gun. It is also referred to as GMAW or MIG welding.
gas shielding A layer of inert gas that protects the weld puddle and arc from atmospheric contamination.
gas tungsten arc welding A very precise arc welding process that uses a nonconsumable tungsten electrode. It is also referred to as GTAW or TIG welding.
insulator A material that inhibits the flow of electricity.
joining A process that brings materials together using either fasteners, adhesives, welding, or similar methods.
joint The meeting point of the two materials that are joined together. Welding creates a permanent joint.
low-carbon steel A steel that has a carbon range between 0.05 and 0.30 percent. Also referred to as mild steel, low-carbon steel is the most commonly welded metal.
mechanical fastening A process that joins two materials using a clamping force. Examples of mechanical fasteners include screws, bolts, and nails.
melting point The temperature at which a solid becomes a liquid. Welding requires metals to reach their melting points.
metal A hard, strong material that conducts electricity and heat, is shiny when polished, and can be bent and formed into shapes.
molten In a liquid state. Molten metals flow as a liquid.
nonconsumable electrode An electrode that conducts electricity to the arc and does not become part of the finished weld.
nonferrous metal A metal that does not contain iron. Non-ferrous metals are more difficult to weld than ferrous metals.
oxyfuel welding A fusion welding process that uses a flame produced by gas containing oxygen and a gas fuel. Oxyfuel welding is also referred to as OFW.
path A conductor that directs electricity in a circuit. The path in welding and other applications is often copper wire.
resistance The opposition to current flow. Electricity flows in the path of least resistance.
scratching A method of striking the arc in which the welder guides the electrode across the workpiece at an angle. The scratching method closely resembles striking a match.
shielded metal arc welding An arc welding process that uses a flux-coated rod. It is also referred to in the shop as SMAW or stick welding.
slag Cooled flux that forms on top of the bead. Slag protects cooling metal and is then chipped off.
spatter Liquid metal droplets expelled from the welding process. Spatter can leave undesirable dots of metal on a workpiece surface.
stainless steel A steel that resists tarnishing. Stainless steel can be welded using many methods.
tapping A method of striking the arc in which the welder moves the electrode downward to the base metal in a vertical direction.
tungsten A gray metal that is very strong at elevated temperatures. Tungsten is used to make nonconsumable electrodes.
UV rays Harmful rays emitted by the arc during welding. UV rays can damage a welder's vision and burn skin.
vaporization The process by which a liquid becomes a gas. Vaporization of a metal can ruin a weld.
voltage The electrical force or pressure that causes current to flow in a circuit. Voltage is measured in volts
volume The amount of space that an object occupies. Solids and liquids have definite volume.
weld puddle The small area of molten metal that forms during welding. The cooled weld puddle forms the permanent joint. A weld puddle is also called a weld pool, molten pool, or molten puddle.
welder Either the person who performs a weld or the power source that provides the electricity needed to perform an arc weld. Printed materials may use both meanings of the term.
welding A joining process that uses heat, pressure, and/or chemicals to fuse two materials together permanently.
weldor A term sometimes used to refer to the person who welds.
work cable The path used in welding to conduct electricity from welder to the workpiece. In welding, the cables are connected to the welder, the workpiece, and electrode, providing a closed electrical circuit.
work clamp The object that, along with the electrode, comes in direct contact with the workpiece during welding. The work clamp is connected to the work cable.
workpiece A part that is being worked on. The workpiece may be subject to cutting, welding, forming or other operations.