B-6 Use Welding Equipment Introduction
Terminology
The following terms will be used throughout this section. A complete list of terms for this section can be found in the Glossary.
- alternating current (AC): An electric current that changes direction back and forth many times per second. It is commonly used in homes and buildings. (Section B-6.3)
- amperes (A): The unit used to measure electric current, or how much electricity is flowing through a circuit. (Section B-6.3)
- arc flash: A painful eye injury caused by exposure to the intense light and radiation from a welding arc. (Section B-6.1)
- arc length: The distance between the welding electrode and the metal being welded. (Section B-6.4)
- arc voltage: The voltage present in a welding circuit after the arc is struck and the current is flowing. (Section B-6.3)
- cracking: Breaks or splits that form in a weld or metal because of stress. (Section B-6.4)
- current: The flow of electricity through a circuit, measured in amperes (A). (Section B-6.3)
- DCEN (direct current electrode negative): A welding setup where the electrode is connected to the negative side of the power source, causing more heat to be concentrated in the workpiece. (Section B-6.3)
- DCEP (direct current electrode positive): A welding setup where the electrode is connected to the positive side of the power source, causing more heat to be concentrated in the electrode. (Section B-6.3)
- dimensional faults: Problems with a weld where the size or shape is different from what the design requires. (Section B-6.4)
- direct current (DC): An electric current that flows in one direction only, from the negative to the positive side of a circuit. It is commonly produced by batteries and some welding machines. (Section B-6.3)
- distortion: A change in the shape of metal caused by heating and cooling during welding. (Section B-6.4)
- electrode angle: The direction or tilt of the electrode when it is held during welding. (Section B-6.4)
- flux: A coating on a welding electrode that helps protect the molten metal from air and keeps the arc stable during welding. (Section B-6.3)
- grounded: Connected safely to the earth so that electrical current can flow away and reduce the risk of electric shock. (Section B-6.1)
- hot cracking: Cracks that form in the weld metal while it is still very hot and starting to cool. (Section B-6.4)
- incomplete penetration: A welding problem where the weld metal does not fully reach or join the bottom of the joint. (Section B-6.4)
- inert gas: A gas that does not react chemically and is used to prevent unwanted reactions such as oxidation or explosions. (Section B-6.1)
- lack of fusion: A welding defect where melted metal does not properly join to the metal beside it. (Section B-6.4)
- lockout: A safety procedure that ensures equipment is completely shut off and cannot be turned on during maintenance or repair. (Section B-6.1)
- overlap: Extra weld metal that spills over the edge of a weld without properly joining to the base metal. (Section B-6.4)
- polarity: The direction of electrical flow in a welding circuit, which affects how heat is distributed between the electrode and the workpiece. (Section B-6.3)
- porosity: Small holes or bubbles in a weld caused by trapped gas. (Section B-6.4)
- purging: The process of removing air or hazardous gases from a space by replacing them with another gas or liquid. (Section B-6.1)
- residual stress: Stress that remains inside metal after it has been heated and cooled. (Section B-6.4)
- respirator: A protective device worn over the nose and mouth to filter harmful fumes, gases, or particles from the air. (Section B-6.1)
- self-contained breathing apparatus (SCBA): A type of respirator that supplies clean air from a tank carried by the user. (Section B-6.1)
- shielded metal arc welding (SMAW): A welding process that uses an electric arc between a coated electrode and the metal to join materials. (Section B-6.1)
- slag inclusion: Pieces of solid material (slag) that become trapped inside the weld. (Section B-6.4)
- speed of travel: How fast the welder moves the electrode along the metal while welding. (Section B-6.4)
- structural discontinuities: Flaws or breaks in a weld that weaken the metal. (Section B-6.4)
- toxic fumes: Harmful gases or airborne particles produced during welding that can cause illness or injury when inhaled. (Section B-6.1)
- undercut: A groove or dip along the edge of a weld that makes the joint weaker. (Section B-6.4)
- ventilation: The movement of fresh air through a space to remove harmful fumes, gases, or heat. (Section B-6.1)
- voltage: The electrical pressure that pushes current through a circuit, measured in volts (V). (Section B-6.3)
- volts (V): The unit used to measure voltage, or the electrical pressure that pushes current through a circuit. (Section B-6.3)
