155 Welding Safety: Basic

Glossary

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A

Abrasive. A material, such as grinding wheels, sanding discs, or wire brushes, used to remove surface contaminants, smooth metal, or prepare a workpiece for welding. OSHA requires proper eye and face protection when using abrasives to prevent injuries from flying particles.
Alloying. The process of adding one or more elements to a base metal to improve its mechanical properties, corrosion resistance, or weldability. Common alloying elements include carbon, nickel, chromium, and molybdenum.
Alternating Current (AC). An electric current that reverses direction periodically. AC welding is commonly used in applications where arc stability and deep penetration are required, such as aluminum welding. OSHA requires proper grounding and insulation when using AC welding equipment to prevent electrical hazards.
Arc Welding. A welding process that uses an electric arc to generate heat and join metals. OSHA mandates the use of appropriate PPE, such as welding helmets and flame-resistant clothing, to protect against burns, radiation, and electric shock.
Arc Welding Electrode. A metal wire or coated rod used in arc welding to carry current and create an arc. Electrodes can be consumable or non-consumable, and OSHA requires proper handling and storage to prevent contamination and exposure to hazardous coatings.

C

Backfire. A momentary reversal of flame into a welding or cutting torch, often caused by improper gas flow or dirty equipment. OSHA requires the use of flashback arrestors to prevent serious accidents related to backfires and flashbacks.
Backhand Welding. A technique in which the welding torch or electrode is angled opposite to the direction of travel. This method is commonly used in shielded metal arc welding (SMAW) and gas welding.
Backing. A material, such as copper, ceramic, or weld metal, placed behind a weld joint to support the molten weld pool and prevent burn-through. OSHA recommends using non-toxic backing materials to prevent hazardous fume production.
Base Metal. The metal being welded, cut, or processed. OSHA welding standards require base metals to be clean and free of contaminants to prevent defects and hazardous fume emissions.
Bend Radius. The smallest radius at which a metal can be bent without cracking or permanently deforming. OSHA requires proper handling and bending techniques to avoid structural failures in welded components.
Bevel. An angled edge prepared on a workpiece to create a groove for welding. Proper beveling improves weld penetration and strength. OSHA requires safe handling of beveling tools to prevent injuries.
Braze Welding. A process that joins metals using a filler metal with a melting point above 450ºC (840ºF) but below the melting point of the base metal. OSHA requires adequate ventilation when braze welding to prevent exposure to hazardous fumes.
Burr. A rough edge or raised area on metal caused by cutting or grinding. OSHA mandates deburring tools and PPE, such as gloves and safety glasses, to prevent injuries from sharp edges.
Butt Joint. A type of weld joint where two pieces of metal are placed edge to edge and welded. OSHA requires proper joint preparation and welding techniques to ensure structural integrity and safety.

C

Cap Pass. The final layer of weld metal applied to a multi-pass weld. OSHA requires cap passes to be defect-free to ensure complete fusion and strength.
Coalescence. The process in which two metal surfaces fuse together during welding, forming a single solid piece. OSHA requires proper welding procedures to ensure complete coalescence and structural soundness.
Complete Fusion. A condition where the weld metal fully fuses with the base metal without any gaps or voids. OSHA welding codes require complete fusion to prevent weld failures.
Complete Joint Penetration (CJP). A weld in which the fusion extends through the full thickness of the base metal. OSHA mandates proper welding techniques to achieve CJP in structural welds.
Covered Electrode. A type of welding electrode with a flux coating that stabilizes the arc and protects the weld pool. OSHA requires proper storage of covered electrodes to prevent moisture contamination.
Crater. A depression in the weld bead that occurs when the arc is stopped. OSHA welding guidelines require proper crater filling to prevent crater cracks and weak welds.
Crater Crack. A crack that forms in a crater due to rapid cooling and shrinkage stresses. OSHA requires welders to properly terminate welds and use backfill techniques to prevent crater cracking.
Cutting Attachment. A tool used with oxy-fuel torches to cut metals. OSHA mandates the use of flashback arrestors and proper gas flow settings when using cutting attachments.
Cylinder. A pressurized container used to store gases such as oxygen, acetylene, argon, or carbon dioxide for welding and cutting. OSHA requires cylinders to be stored upright, secured, and kept away from heat sources to prevent leaks, explosions, and fire hazards.

D

Deposited Metal. The weld metal that has been added to the joint during welding. OSHA welding codes ensure that deposited metal meets strength and durability requirements for structural integrity.
Deposition Efficiency. The percentage of filler metal that becomes part of the weld versus the amount lost as spatter or slag. OSHA encourages efficient deposition to minimize material waste and welding hazards.
Deposition Rate. The amount of weld metal deposited in a given period, typically measured in pounds per hour. OSHA requires controlled deposition rates to ensure weld quality and prevent overheating.
Depth of Fusion. The distance the weld metal penetrates into the base metal. OSHA welding standards require sufficient fusion depth to ensure strong and defect-free welds.
Direct Current (DC). A type of electric current that flows in one direction. DC is often used in welding due to its stable arc and deep penetration. OSHA mandates proper insulation and grounding of DC welding equipment.
Direct Current Electrode Negative (DCEN). A polarity setting in which the electrode is connected to the negative terminal and the workpiece is positive. DCEN provides higher deposition rates and is commonly used in TIG welding.
Direct Current Electrode Positive (DCEP). A polarity setting in which the electrode is connected to the positive terminal and the workpiece is negative. DCEP provides deeper penetration and is commonly used in stick welding (SMAW).
Duty Cycle. The percentage of time a welding machine can operate at a given amperage within a 10-minute period without overheating. OSHA recommends adherence to duty cycle ratings to prevent equipment failure and worker injury.

E

Edge Joint. A type of weld joint where two metal pieces are placed parallel to each other and welded along the edges. OSHA requires proper joint preparation and penetration for edge joints to ensure structural integrity.
Edge Preparation. The process of preparing the edges of metal pieces before welding, such as beveling, chamfering, or cleaning, to improve weld quality. OSHA mandates proper edge preparation to ensure complete fusion and prevent defects.
Electrode. A metal wire or rod that conducts electricity to create an arc for welding. Electrodes can be consumable (such as in SMAW or MIG welding) or non-consumable (as in TIG welding). OSHA requires proper storage and handling of electrodes to prevent contamination and ensure weld quality.
Electrode Coating. A flux layer covering certain types of electrodes (such as those used in SMAW) that helps stabilize the arc, protect the weld from oxidation, and improve mechanical properties. OSHA requires proper ventilation when using coated electrodes to prevent inhalation of toxic fumes.
Electrode Holder. A clamp-like device that holds the electrode in place during welding and connects it to the power source. OSHA requires insulated electrode holders to prevent electrical shock hazards.
Electrode Lead. The cable that connects the welding electrode holder to the welding power source. OSHA mandates regular inspection of electrode leads to prevent insulation damage and electrical hazards.
Electrode Stick-Out. The length of the electrode extending beyond the contact tip in MIG or flux-cored welding. Proper stick-out distance is essential for arc stability and penetration. OSHA welding standards recommend maintaining correct stick-out to prevent defects and overheating.
Electroslag Welding (ESW). A welding process that uses a molten slag to conduct electricity and generate heat, typically used for thick-section welding. OSHA requires proper ventilation and shielding when using ESW due to intense heat and fume production.
Electron Beam Welding (EBW). A high-precision welding process that uses a focused beam of electrons to melt and join metal. OSHA requires strict safety measures, such as shielding from X-ray radiation and vacuum chamber usage, to protect workers from exposure hazards.
Elongation. A material property that measures how much a metal stretches before breaking. OSHA welding codes specify minimum elongation requirements for welded joints to ensure adequate ductility and resistance to cracking.
End Crater. A depression at the end of a weld bead caused by improper arc termination. OSHA welding guidelines require proper crater filling to prevent crater cracking and weak welds.
Expansion Joint. A designed gap or flexible connection in welded structures that allows movement due to thermal expansion or contraction. OSHA mandates proper placement and design of expansion joints to prevent weld failures under stress.

F

Filler Material. The metal added to a weld joint to facilitate bonding. OSHA welding standards specify filler material requirements based on strength, corrosion resistance, and compatibility with the base metal.
Fillet Weld. A triangular weld that joins two surfaces at right angles. OSHA requires fillet welds to meet size and penetration requirements to ensure joint strength and safety.
Filter Plate. A protective lens used in welding helmets to shield the eyes from harmful ultraviolet and infrared radiation. OSHA mandates the use of filter plates with appropriate shade levels based on welding amperage.
Flat Welding Position. A welding position in which the workpiece is horizontal, allowing gravity to assist in forming the weld bead. OSHA welding codes define position classifications to standardize weld quality and safety.
Flashback. A dangerous condition in oxy-fuel welding and cutting where the flame travels back into the torch and hose, potentially causing explosions. OSHA requires flashback arrestors on fuel and oxygen lines to prevent accidents.
Flux. A chemical substance used in welding and brazing to prevent oxidation and remove impurities from the weld pool. OSHA requires proper ventilation when using fluxes to avoid inhalation of hazardous fumes.
Forehand Welding. A welding technique where the torch or electrode is pointed in the direction of welding travel. This method is commonly used in oxy-fuel welding for better heat control.
Fusion. The process of melting and joining metals during welding. OSHA welding standards require complete fusion to prevent weak joints and structural failures.

G

Gas Metal Arc Welding (GMAW). A welding process, also known as MIG (Metal Inert Gas) welding, that uses a continuously fed wire electrode and a shielding gas to create a weld. OSHA requires proper ventilation, PPE, and fire protection when performing GMAW to prevent exposure to harmful fumes and arc flash.
Gas Tungsten Arc Welding (GTAW). Also known as TIG (Tungsten Inert Gas) welding, GTAW uses a non-consumable tungsten electrode to produce high-quality, precise welds. OSHA mandates proper ventilation and PPE to protect against UV radiation and hazardous metal fumes.
Gas Welding. A welding process that uses a flame produced by burning a fuel gas with oxygen to melt and join metals. OSHA requires proper gas cylinder storage, leak detection, and flashback arrestors to prevent fire and explosion hazards.
Globular Transfer. A metal transfer mode in Gas Metal Arc Welding (GMAW) where large droplets of molten metal form on the wire and transfer irregularly to the weld pool. OSHA welding standards require proper voltage and shielding gas selection to control spatter and improve weld quality.
Ground Clamp. A device that connects the work lead to the workpiece to complete the electrical circuit in welding. OSHA requires proper grounding to prevent electric shock and ensure stable arc performance.
Ground Connection. The point where the welding circuit is completed by attaching the work lead to the workpiece or welding table. OSHA mandates proper grounding techniques to reduce electrical hazards and equipment malfunctions.
Groove Angle. The total angle between the two workpieces in a groove weld. OSHA requires specific groove angles for different welding applications to ensure proper fusion and joint strength.
Groove Face. The surface of a workpiece that is prepared for welding in a groove joint. OSHA requires proper surface preparation to remove contaminants and ensure defect-free welds.
Groove Weld. A type of weld made in a groove prepared between two workpieces. OSHA requires proper joint preparation and welding techniques to achieve full penetration and avoid defects such as incomplete fusion or porosity.
Gun Liner. A replaceable tube inside a welding gun that guides the welding wire from the drive rollers to the contact tip. OSHA recommends regular maintenance and replacement of gun liners to prevent wire feeding issues that could lead to arc instability.
Gas Cylinder Valve. A valve on a compressed gas cylinder that controls the flow of gases used in welding and cutting operations. OSHA requires gas cylinder valves to be turned off when not in use and protected from damage to prevent leaks and explosions.
Gas Flow Rate. The rate at which shielding gas is delivered to the weld pool, typically measured in cubic feet per hour (CFH) or liters per minute (LPM). OSHA welding standards require proper gas flow settings to prevent contamination and ensure weld quality.
Gas Nozzle. A component of a welding torch or gun that directs shielding gas to the weld pool. OSHA mandates proper nozzle cleaning and maintenance to prevent contamination and ensure consistent gas coverage.
Gas Pressure Regulator. A device that controls the pressure of gases supplied from a cylinder to a welding or cutting torch. OSHA requires regulators to be properly rated for the gas in use and inspected regularly for leaks or damage.
Gas Shielding. The use of an inert or semi-inert gas to protect the weld area from atmospheric contamination. OSHA requires welders to use proper shielding gas mixtures and flow rates to prevent weld defects.
Gas-Cooled Torch. A type of welding torch that uses the flow of shielding gas to dissipate heat instead of a liquid cooling system. OSHA mandates proper gas flow settings and torch handling to prevent overheating.
Gas-Filled Porosity. A weld defect caused by trapped gas bubbles in the solidified weld metal. OSHA requires proper shielding gas selection and welding techniques to prevent porosity and ensure weld integrity.
Gas-Cutting Torch. A tool used in oxy-fuel cutting to produce a high-temperature flame that melts and removes metal. OSHA requires flashback arrestors, proper gas mixture settings, and fire prevention measures when using gas-cutting torches.
Gas Purging. The process of filling a weld joint with an inert gas to prevent oxidation during welding, commonly used in stainless steel and titanium applications. OSHA requires proper ventilation and gas monitoring to ensure worker safety during purging.
Grain Growth. The increase in size of metal grains in the heat-affected zone due to excessive heat input. OSHA welding standards recommend controlled heating and cooling to minimize grain growth and maintain mechanical properties.
Grinding. A process used to remove excess weld metal, smooth surfaces, or prepare base metals for welding. OSHA requires welders to wear face shields, eye protection, and respiratory protection when grinding to prevent exposure to airborne particles and sparks.

H

Hardfacing. A welding process in which a wear-resistant metal layer is applied to a surface to improve durability, abrasion resistance, or impact resistance. OSHA requires proper ventilation and PPE when welding hardfacing materials that contain hazardous elements, such as chromium or tungsten carbide.
Heat-Affected Zone (HAZ). The area of base metal surrounding a weld that has experienced thermal changes but was not melted. OSHA requires proper preheating and cooling techniques to minimize the risk of cracking and brittleness in the HAZ.
Heat Input. The amount of heat energy applied to the workpiece during welding, typically measured in joules per inch. OSHA welding codes specify acceptable heat input ranges to prevent overheating, warping, and weld defects.
Heat Treatment. A controlled heating and cooling process used to modify the mechanical properties of a welded material. OSHA mandates post-weld heat treatment (PWHT) in certain applications to relieve stress and improve weld integrity.
Heliarc Welding. A former trade name for Gas Tungsten Arc Welding (GTAW), commonly known as TIG welding. OSHA requires PPE and ventilation for GTAW to minimize exposure to ultraviolet radiation and hazardous fumes.
Helium (He). An inert gas often used in shielding gas mixtures for TIG and MIG welding. Helium provides deeper penetration and higher heat input. OSHA mandates proper gas handling and storage procedures to prevent leaks and asphyxiation hazards.
High-Frequency Start. A technique used in TIG welding to initiate an arc without touching the workpiece, preventing tungsten contamination. OSHA requires safe operation of high-frequency welding equipment to minimize electrical hazards.
Horizontal Welding Position. A welding position where the weld axis is horizontal, commonly referred to as the "2G" (groove weld) or "2F" (fillet weld) position. OSHA welding codes define position classifications to ensure consistent weld quality and safety.
Hot Cracking. A weld defect that occurs at high temperatures during solidification, often caused by excessive heat input, stress, or improper filler metal selection. OSHA welding standards require proper cooling rates and material selection to prevent hot cracking.
Hot Pass. A secondary weld pass that helps remove slag, smooth the root pass, and improve penetration. OSHA welding codes require proper control of heat input during hot passes to prevent excessive distortion and residual stress.
Hot Work. Any process that generates heat, flames, or sparks, including welding, cutting, and grinding. OSHA requires hot work permits in fire-prone areas and mandates fire watches to monitor for hazards.
Hydrogen Embrittlement. A condition where hydrogen atoms diffuse into metal, making it brittle and prone to cracking. OSHA welding standards require proper electrode storage, preheating, and post-weld heat treatment to prevent hydrogen embrittlement.

I

Ignition Temperature. The minimum temperature at which a material will ignite and sustain combustion. OSHA requires proper storage and handling of flammable materials in welding areas to prevent fire hazards.
Impact Strength. The ability of a welded joint or material to withstand sudden impact forces without fracturing. OSHA welding codes specify minimum impact strength requirements for critical applications, such as structural welding.
Induction Brazing. A brazing process that uses high-frequency electromagnetic fields to generate heat and join metals with a filler material. OSHA requires shielding and protective measures to prevent burns and exposure to high-frequency radiation.
Induction Hardening. A heat treatment process that uses induction heating to harden the surface of a metal component, improving wear resistance. OSHA requires protective equipment and controlled cooling to prevent worker exposure to excessive heat.
Induction Heating. A process that uses electromagnetic induction to generate heat within a conductive material without direct contact. OSHA mandates safety protocols, such as shielding and proper PPE, to prevent burns and high-frequency exposure risks.
Induction Welding. A welding process that uses high-frequency electromagnetic fields to generate heat and fuse metals without direct contact. OSHA requires electromagnetic field exposure limits and proper grounding techniques to ensure worker safety.
Inert Atmosphere. An environment containing inert gases, such as argon or helium, used to protect the weld pool from oxidation. OSHA requires proper ventilation and gas handling to prevent asphyxiation hazards in enclosed workspaces.
Infrared Heating. A heat source used in welding preheating and post-weld heat treatment (PWHT) that emits infrared radiation to gradually heat metal surfaces. OSHA mandates eye and skin protection when working with infrared heating sources.
Intergranular Corrosion. A type of corrosion that occurs along the grain boundaries of a metal, often due to improper welding techniques or exposure to high temperatures. OSHA welding standards require proper filler materials and post-weld treatments to prevent intergranular corrosion.
Interpass Temperature. The temperature of a weld joint between successive weld passes. OSHA welding codes specify interpass temperature limits to prevent weld cracking and distortion.
Interpass Cleaning. The removal of slag, spatter, and oxidation between weld passes to ensure proper fusion. OSHA requires proper cleaning techniques, such as wire brushing or grinding, to prevent weld defects.
Internal Stress. Residual stress within a welded structure due to thermal expansion and contraction. OSHA welding standards require stress relief techniques, such as post-weld heat treatment (PWHT), to reduce internal stress and prevent cracking.
Iron Powder Electrode. A covered electrode containing iron powder in the flux coating, increasing deposition efficiency and weld strength. OSHA requires proper ventilation when using these electrodes due to increased fume generation.
ISO Welding Standards. International Organization for Standardization (ISO) standards that define welding quality, safety, and inspection procedures. OSHA welding regulations often align with ISO standards to ensure international compliance and worker protection.

J

Joint. The location where two or more metal pieces are joined by welding, brazing, or soldering. OSHA welding standards classify joint types to ensure proper preparation, penetration, and weld strength.
Joint Design. The specific configuration of a weld joint, including factors such as bevel angles, root openings, and weld size. OSHA welding codes require proper joint design for structural integrity and safety.
Joint Efficiency. A numerical value representing the strength of a welded joint compared to the base metal. OSHA and industry standards specify joint efficiency requirements for pressure vessels, piping, and structural components.
Joint Fit-Up. The alignment and spacing of materials before welding. Proper fit-up is crucial for achieving complete fusion and preventing defects. OSHA welding standards require inspections of joint fit-up to ensure consistent weld quality.
Joint Penetration. The depth to which a weld extends into the base metal. Complete joint penetration (CJP) welds are required in many structural and pressure applications to ensure maximum strength. OSHA welding codes regulate minimum penetration depths for safety-critical welds.
Joule (J). The unit of measurement for energy, including the heat input in welding. OSHA welding safety guidelines consider heat input in preventing material distortion, cracking, and excessive residual stress.
Judder. A vibration or irregular movement that can occur in welding equipment or workpieces due to improper setup or unstable arc conditions. OSHA welding guidelines recommend checking equipment calibration and workpiece stability to prevent defects caused by judder.

K

Kerf. The width of material removed during a cutting process, such as oxy-fuel or plasma cutting. OSHA requires proper ventilation when cutting metals to prevent exposure to hazardous fumes and particulates.
Keyhole. A small hole that forms in the weld pool during deep penetration welding, such as plasma arc or laser welding. OSHA welding standards ensure proper keyhole control to prevent weld defects.

L

Lap Joint. A type of weld joint where two overlapping metal pieces are joined. OSHA welding codes require adequate weld size and penetration to ensure joint strength.
Liquidus. The temperature at which a metal becomes fully molten. OSHA requires proper temperature control during welding to prevent overheating and material damage.
Lamellar Tear. A type of crack that forms in rolled steel due to stresses in the through-thickness direction, often caused by welding. OSHA requires proper joint design and material selection to prevent lamellar tearing.
Lamination. A type of discontinuity in metal caused by rolling defects during manufacturing, which can weaken welds. OSHA requires material inspection and proper welding techniques to prevent failure due to laminations.
Leg of a Fillet Weld. The distance from the root of a fillet weld to the toe of the weld. OSHA welding standards specify proper fillet weld leg size for structural integrity.
Linear Indication. A weld defect that appears as a continuous line, often due to cracks, lack of fusion, or incomplete penetration. OSHA requires weld inspections to detect and repair linear indications before service.
Lack of Fusion. A weld defect where the weld metal does not fully fuse with the base metal or previous weld pass. OSHA welding codes require proper heat input and technique to ensure complete fusion.
Lack of Penetration. A weld defect where the weld metal does not penetrate fully into the joint, reducing strength. OSHA mandates proper joint preparation and welding technique to ensure full penetration where required.
Low Hydrogen Electrode. A type of welding electrode designed to minimize hydrogen pickup and reduce the risk of hydrogen-induced cracking. OSHA requires proper storage of low hydrogen electrodes in dry conditions to prevent moisture absorption.
Load-Carrying Weld. A weld that is subject to structural loads and stresses. OSHA welding standards require specific design and inspection criteria for load-carrying welds to ensure safety.
Liquid Penetrant Testing (LPT). A non-destructive testing (NDT) method used to detect surface defects in welds and metal surfaces. OSHA mandates proper use of penetrant testing to identify cracks, porosity, and lack of fusion.
Lug. A welded attachment, often used for lifting points or connections in structural components. OSHA requires proper welding and inspection of lugs to ensure load-bearing capacity.
Linear Porosity. A series of gas pockets or voids aligned in a straight line within a weld, which can weaken the joint. OSHA welding standards require proper shielding gas coverage and electrode selection to prevent linear porosity.

M

Melting Range. The temperature range between the solidus and liquidus points of a metal. OSHA welding standards require controlled heating to prevent overheating and warping.
Melt-Through. A welding condition where the weld metal fully penetrates the base metal, sometimes intentionally in full penetration welds or unintentionally as a defect. OSHA mandates proper control of heat input to prevent excessive melt-through.
Metal Cored Wire. A tubular welding electrode filled with metal powders and fluxing agents, designed for high deposition rates and improved weld quality. OSHA requires proper fume extraction when using metal cored wires to minimize exposure to hazardous welding fumes.
Metal Transfer. The way molten metal moves from the electrode to the weld pool in welding processes. Common types include short-circuit, globular, and spray transfer. OSHA mandates proper voltage and wire feed settings to control metal transfer and reduce spatter.
Microcracking. Small, microscopic cracks that form in the weld metal or heat-affected zone due to excessive residual stress, hydrogen embrittlement, or improper cooling. OSHA welding standards require proper preheating and post-weld treatments to prevent microcracking.
Microstructure. The internal structure of a welded metal, including grain size and phase composition, which determines the weld's mechanical properties. OSHA standards specify heat treatment processes to optimize microstructure for strength and toughness.
MIG Welding (Metal Inert Gas Welding). Also known as Gas Metal Arc Welding (GMAW), this welding process uses a continuously fed wire electrode and shielding gas to produce the weld. OSHA requires proper ventilation and fume extraction when MIG welding to prevent exposure to hazardous fumes.
Mill Scale. A layer of iron oxide that forms on steel surfaces during hot rolling. It must be removed before welding to ensure proper fusion and prevent weld defects. OSHA recommends mechanical or chemical cleaning methods to eliminate mill scale before welding.
Misalignment. A condition where welded components are not properly aligned, leading to weak joints and stress concentrations. OSHA welding standards require proper joint preparation and fixture use to minimize misalignment.
Molten Pool. The area of liquid metal created during the welding process. OSHA requires proper heat control to maintain a stable molten pool and prevent defects such as porosity and cracking.
Multi-Pass Welding. A welding technique where multiple weld passes are applied to build up the weld joint. OSHA requires controlled heat input and interpass temperature to prevent cracking and distortion in multi-pass welds.
Metal Fume Fever. A flu-like illness caused by inhaling zinc, copper, or magnesium fumes generated during welding or cutting galvanized steel. OSHA requires proper ventilation, fume extraction, and the use of respiratory protection to prevent metal fume fever.
Magnetic Arc Blow. A welding defect caused by magnetic fields affecting the arc, leading to arc instability and incomplete fusion. OSHA welding standards recommend proper work lead placement and alternating polarity to reduce arc blow effects.
Metal Powder Welding. A welding process in which powdered metal is added to the weld pool to improve mechanical properties and wear resistance. OSHA requires adequate fume extraction due to the potential for airborne metal particles.
Macro Etching. A testing process where a welded joint is chemically etched to reveal internal defects, grain structure, and penetration. OSHA welding inspection guidelines often require macro etching as part of weld quality evaluation.
Melting Efficiency. The percentage of heat energy from the welding process that contributes to melting the base metal and filler metal. OSHA welding guidelines encourage efficient energy use to optimize weld quality and minimize material waste.
Molten Slag. The layer of non-metallic material that forms over a weld bead when using flux-coated electrodes or flux-cored wire. OSHA requires proper slag removal techniques to ensure strong, defect-free welds.
Metal Deposition. The process of adding filler metal to a weld joint. OSHA welding codes regulate deposition rates to ensure weld strength and prevent excessive heat input that can weaken the joint.
Magnesium Welding. The process of welding magnesium and its alloys, requiring special shielding gases and heat control. OSHA mandates proper ventilation when welding magnesium due to the risk of highly flammable magnesium dust.
Manual Welding. A welding process performed entirely by hand, requiring skill and control of the torch or electrode. OSHA welding safety regulations emphasize proper PPE, ventilation, and training for manual welding operators.

N

NDT (Non-Destructive Testing). A testing method used to evaluate the quality of welds without causing damage to the welded component. OSHA requires NDT in critical applications to detect internal and surface defects such as cracks, porosity, and incomplete fusion. Common NDT methods include ultrasonic testing (UT), radiographic testing (RT), and magnetic particle testing (MT).
Neutral Flame. A properly balanced oxy-fuel flame with equal amounts of oxygen and fuel gas, producing a clear and efficient combustion with minimal oxidation. OSHA welding standards emphasize correct flame adjustment to prevent defects and ensure proper metal fusion.
Nick Break Test. A destructive testing method used to evaluate the internal quality of a weld by breaking a sample and inspecting the fractured surface for defects such as porosity and incomplete fusion. OSHA requires proper testing techniques to assess weld integrity in critical applications.
Nickel Alloy. A type of metal alloy containing nickel, often used in high-temperature and corrosion-resistant welding applications. OSHA mandates proper ventilation and PPE when welding nickel alloys to prevent exposure to hazardous fumes.
Nitriding. A heat treatment process that introduces nitrogen into the surface of steel to improve hardness and wear resistance. OSHA requires controlled environments when performing nitriding to prevent hazardous gas exposure.
Noble Gas. A group of inert gases, including argon and helium, commonly used as shielding gases in welding to protect the weld pool from atmospheric contamination. OSHA mandates proper handling and storage of noble gases to prevent asphyxiation risks.
Non-Ferrous Metal. Metals that do not contain iron, such as aluminum, copper, and titanium. OSHA requires specific welding techniques and safety precautions when welding non-ferrous metals to prevent contamination and hazardous fume exposure.
Non-Preheat Welding. Welding performed without preheating the base metal. OSHA welding codes specify when preheating is necessary to prevent cracking and ensure weld quality.
Non-Spatter Electrode. A welding electrode designed to minimize spatter, improving weld quality and reducing cleanup time. OSHA requires the selection of appropriate electrodes for each welding application to optimize safety and efficiency.
Nozzle. A component on a welding or cutting torch that directs the shielding gas or flame to the weld area. OSHA requires regular maintenance and proper selection of nozzles to ensure stable gas flow and prevent flashbacks.
Nozzle Cleaning Station. A device used to remove spatter and debris from welding torch nozzles, ensuring consistent gas flow. OSHA welding standards recommend regular cleaning of nozzles to maintain weld quality and prevent defects.

O

Open-Circuit Voltage (OCV). The voltage between the output terminals of a welding power source when no welding current is flowing. OSHA mandates proper electrical safety measures to prevent electric shock hazards associated with high OCV.
Oscillation. A side-to-side or circular motion used when welding to create a wider bead or improve fusion. OSHA welding guidelines recommend proper oscillation techniques to ensure even heat distribution and prevent weld defects.
Out-of-Position Welding. Any welding performed in positions other than flat, such as vertical, overhead, or horizontal welding. OSHA welding codes classify welding positions and require special techniques and safety measures for out-of-position welding.
Overhead Welding. A welding position where the weld is performed on the underside of a joint, requiring the welder to work from below. OSHA mandates proper PPE, including flame-resistant clothing, to protect against falling sparks and molten metal.
Overlap. A welding defect where the weld metal extends beyond the joint and fails to fuse with the base metal. OSHA welding standards require proper heat control and technique to prevent overlap and ensure strong welds.
Oxidation. A chemical reaction between metal and oxygen that can lead to rust, scale, or weld contamination. OSHA requires proper shielding gas coverage and cleaning techniques to minimize oxidation during welding.
Oxide Inclusion. A weld defect caused by trapped oxides within the weld metal, leading to weakened joints. OSHA welding procedures require thorough surface cleaning and proper shielding gas to prevent oxide inclusions.
Oxygen Cutting. A cutting process that uses oxygen and fuel gas to generate a high-temperature flame to sever metal. OSHA requires the use of flashback arrestors and proper ventilation to prevent fire hazards and exposure to toxic fumes.
Oxygen Cylinder. A high-pressure container used to store oxygen for welding and cutting applications. OSHA mandates that oxygen cylinders be stored separately from fuel gas cylinders, secured upright, and protected from heat and impact to prevent explosions.
Oxygen-Fuel Gas Welding. A welding process that uses a flame produced by burning a fuel gas, such as acetylene, with oxygen. OSHA requires proper gas cylinder handling, leak detection, and PPE to prevent fire and explosion hazards.

P

Passivation. A chemical process used to remove surface contaminants, such as oxides and free iron, from stainless steel welds to enhance corrosion resistance. OSHA requires proper handling of passivation chemicals to prevent exposure to hazardous fumes.
Peening. The mechanical process of striking a weld surface with a hammer or specialized tool to relieve stress and improve ductility. OSHA recommends controlled peening to prevent weld damage and worker injury.
Penetration. The depth to which the weld metal fuses into the base metal. OSHA welding codes specify minimum penetration requirements to ensure strong, defect-free welds.
Perlite. A microstructure found in carbon steel that forms when the metal cools slowly after welding. OSHA welding guidelines recommend proper cooling rates to control microstructure and mechanical properties.
Plasma Arc Cutting (PAC). A cutting process that uses a high-velocity jet of ionized gas (plasma) to cut through metal. OSHA requires proper PPE, ventilation, and fire prevention measures when using plasma cutting equipment.
Plug Weld. A circular weld made by filling a hole in one workpiece to join it to another piece underneath. OSHA welding codes specify plug weld dimensions and penetration requirements to ensure strength.
Polarity. The direction of electrical flow in a welding circuit, which affects penetration and heat distribution. OSHA requires proper polarity selection to optimize weld quality and prevent defects.
Porosity. A weld defect caused by trapped gas pockets within the weld metal. OSHA requires proper shielding gas coverage, electrode selection, and surface preparation to prevent porosity.
Post-Flow Time. The duration that shielding gas continues to flow after the welding arc is extinguished. OSHA requires proper post-flow settings to protect the weld pool from oxidation.
Post-Heating. The controlled heating of a weld after completion to reduce residual stresses and prevent cracking. OSHA welding codes define post-heating requirements for specific materials.
Post Weld Heat Treatment (PWHT). A heat treatment process applied to a welded component to relieve residual stresses, improve mechanical properties, and reduce hardness. OSHA welding codes specify PWHT requirements for certain materials and applications.
Preheating. The controlled heating of a base metal before welding to reduce thermal stress, minimize distortion, and prevent cracking. OSHA requires preheating in certain welding applications, especially for high-carbon steels.
Prequalified Welding Procedure. A welding procedure that has been previously tested and approved without requiring further qualification testing. OSHA welding standards reference industry codes, such as AWS D1.1, for prequalified procedures.
Procedure Qualification Record (PQR). A formal document that records the results of welding procedure qualification tests. OSHA welding codes require PQR documentation to ensure compliance with safety and quality standards.

Q

Quenching. The rapid cooling of a metal, typically using water, oil, or air, to increase hardness and strength. OSHA requires proper handling of quenched materials to prevent cracking and residual stress buildup.
Quality Assurance (QA). A set of procedures and inspections used to ensure that welds meet specified standards and requirements. OSHA welding regulations require QA programs to verify weld integrity and safety.
Quality Control (QC). The process of inspecting and testing welds to detect defects such as cracks, porosity, and incomplete fusion. OSHA mandates QC procedures to ensure compliance with welding safety and performance standards.
Quench Crack. A crack that forms in metal due to excessive stress caused by rapid cooling. OSHA welding standards require controlled cooling processes to prevent quench cracking in welded components.

R

Reactive Gas. A gas, such as oxygen or carbon dioxide, that reacts with molten metal during welding to influence the weld properties. OSHA requires proper handling and ventilation when using reactive gases to prevent hazards.
Residual Stress. Internal stresses that remain in a welded component after cooling, which can lead to distortion or cracking. OSHA welding codes require stress relief treatments to minimize these stresses in critical applications.
Reverse Polarity. A welding polarity setting where the electrode is connected to the positive terminal and the workpiece to the negative terminal, also known as Direct Current Electrode Positive (DCEP). OSHA requires correct polarity settings to optimize weld penetration and arc stability.
Rod Oven. A temperature-controlled storage device used to keep welding electrodes dry and prevent moisture absorption. OSHA recommends using rod ovens for low-hydrogen electrodes to prevent weld defects like hydrogen-induced cracking.
Root Crack. A weld defect that forms at the root of a weld joint, often caused by excessive stress, improper fusion, or shrinkage during cooling. OSHA welding guidelines emphasize proper welding techniques and preheating to reduce the risk of root cracks.
Root Face. The surface of the base metal at the root of the weld joint before welding. OSHA welding codes specify root face dimensions to ensure proper penetration and fusion.
Root Opening. The gap between two pieces of metal at the root of a joint before welding. OSHA welding standards specify root opening dimensions to ensure adequate penetration and weld strength.
Root Pass. The first weld pass made in a multi-pass weld joint, which establishes fusion at the base of the joint. OSHA welding standards require root passes to be free of defects to ensure strong weld integrity.
Root Reinforcement. The additional weld metal beyond the root of the joint, which increases strength and penetration. OSHA welding codes define acceptable limits for root reinforcement to ensure structural stability.
Run-In Length. The distance a welding electrode travels before stabilizing the arc and depositing a consistent weld bead. OSHA welding standards emphasize proper run-in length control to prevent arc instability and defects.
Run-Out Length. The distance from the end of the weld bead to the point where the arc is extinguished. OSHA welding procedures specify controlled run-out techniques to prevent crater cracks and weak terminations.

S

Safety Data Sheet (SDS). A document that provides information on the properties, hazards, and safe handling of welding materials, such as electrodes, shielding gases, and fluxes. OSHA requires SDSs to be accessible to workers to ensure proper hazard communication.
Seal Weld. A weld applied to prevent leakage or protect against environmental exposure rather than for structural strength. OSHA welding standards may require seal welds in pressure vessels and piping applications.
Shielded Metal Arc Welding (SMAW). A manual arc welding process that uses a flux-coated electrode to generate a protective gas shield, preventing contamination. OSHA mandates PPE and proper ventilation to protect workers from welding fumes and arc radiation.
Shielding Gas. A gas, such as argon, helium, or carbon dioxide, used to protect the weld pool from atmospheric contamination. OSHA requires proper storage, handling, and leak detection of shielding gases to prevent asphyxiation and explosion hazards.
Slag. A layer of non-metallic material that forms on top of a weld due to flux decomposition. It protects the molten weld from oxidation and must be removed after welding. OSHA welding codes require slag removal to ensure proper weld inspection and quality.
Slag Inclusion. A welding defect caused by trapped slag within the weld metal, leading to weakened joints. OSHA welding standards require proper slag removal between weld passes to prevent inclusion defects.
Solid-State Welding. A group of welding processes that join metals without melting them, such as friction welding and ultrasonic welding. OSHA requires proper safety measures when using high-pressure and high-speed welding techniques.
Soldering. A joining process that uses a filler metal with a melting point below 450ºC (840ºF) to bond metal parts without melting the base metal. OSHA requires adequate ventilation and PPE to protect workers from lead and flux fumes.
Solidus. The highest temperature at which a metal remains completely solid before it begins to melt. OSHA welding standards emphasize proper temperature control to avoid overheating and structural failure.
Spalling. The breaking or chipping of a surface due to thermal stress or impact, often occurring in welded materials exposed to extreme heat. OSHA welding safety guidelines require proper material selection and heat treatment to minimize spalling risks.
Spatter. Small droplets of molten metal expelled during welding, which can cause burns, damage equipment, and result in poor weld appearance. OSHA mandates proper PPE and controlled welding parameters to reduce spatter.
Staggered Intermittent Weld. A series of welds placed on alternating sides of a joint to reduce distortion and stress concentration. OSHA welding standards define spacing and sizing requirements for staggered welds in structural applications.
Stress Corrosion Cracking (SCC). A type of cracking that occurs in welded materials exposed to tensile stress and corrosive environments. OSHA welding standards require material selection and stress relief techniques to prevent SCC.
Stress Relief Cracking. A form of cracking that occurs in the heat-affected zone of welded metals due to residual stress and embrittlement. OSHA mandates post-weld heat treatment (PWHT) in certain applications to prevent this defect.
Stress Relief Treatment. A controlled heating and cooling process used to reduce residual stresses in welded components. OSHA welding standards require stress relief treatment for certain materials and high-stress applications to prevent cracking.
Stringer Bead. A weld bead applied with little or no weaving motion along the joint. OSHA welding codes specify proper bead placement to ensure good fusion and minimize defects.
Submerged Arc Welding (SAW). A welding process that uses a continuously fed wire electrode and a granular flux that covers the arc, protecting it from contamination. OSHA requires proper ventilation and flux handling to prevent exposure to hazardous fumes.
Surface Tension. The cohesive force that holds molten metal together in a weld pool. OSHA welding guidelines recommend controlling heat input and travel speed to manage surface tension for a smooth weld bead.
Synergic Welding. A welding technique where machine settings are automatically adjusted based on pre-programmed parameters. OSHA welding safety guidelines encourage the use of synergic welding systems to reduce errors and improve consistency.

T

Tack Weld. A small, temporary weld used to hold parts in place before final welding. Tack welds help prevent distortion and misalignment. OSHA requires tack welds to be properly placed and strong enough to support the structure during welding.
Temper Colors. Oxidation colors that appear on metal surfaces when heated, indicating temperature levels. In welding, temper colors can help assess the heat-affected zone (HAZ). OSHA requires proper control of heating and cooling to prevent overheating and metal weakening.
Temper Brittleness. A condition where steel becomes brittle after being heated to certain temperatures and then cooled. This can occur in the heat-affected zone of welds. OSHA requires proper post-weld heat treatment (PWHT) to minimize temper brittleness.
Tempering. A heat treatment process that reduces hardness and brittleness in welded or heat-treated metals while maintaining strength. OSHA welding codes specify tempering requirements for high-strength steels to prevent cracking.
Tensile Strength. The maximum stress a weld or material can withstand before breaking under tension. OSHA welding codes specify minimum tensile strength requirements for different welding applications to ensure structural integrity.
Thermal Cutting. A process that uses heat to cut metal, including oxy-fuel cutting, plasma cutting, and laser cutting. OSHA requires proper ventilation and PPE when using thermal cutting to prevent burns, fume exposure, and fire hazards.
Thermal Expansion. The increase in the size of a material when heated. In welding, thermal expansion can cause distortion and stress in welded joints. OSHA recommends preheating and controlled cooling to minimize thermal expansion effects.
Thermal Stress. Stress caused by uneven heating and cooling during welding, leading to warping or cracking. OSHA welding codes require stress-relief treatments to reduce thermal stress in critical welds.
Thermit Welding. A fusion welding process that uses an exothermic chemical reaction between aluminum powder and metal oxides to produce molten metal. OSHA requires protective clothing and proper handling of reactive materials to prevent burns and fire hazards.
TIG Welding (Tungsten Inert Gas Welding). Also known as Gas Tungsten Arc Welding (GTAW), this process uses a non-consumable tungsten electrode to create high-quality welds. OSHA mandates proper PPE, ventilation, and fume control when welding materials that produce hazardous fumes, such as stainless steel and aluminum.
Toe Crack. A weld defect that occurs at the junction of the weld bead and the base metal, often due to excessive stress or improper welding technique. OSHA requires thorough inspection and repair of toe cracks to maintain weld integrity.
Toe of Weld. The point where the weld bead meets the base metal. Proper weld toe blending is required to prevent stress concentration and cracking. OSHA welding codes specify acceptable weld toe profiles to ensure structural strength.
Torch Standoff Distance. The distance between the welding or cutting torch and the workpiece. Maintaining the correct standoff distance is essential for stable arc control and proper penetration. OSHA welding standards emphasize proper standoff distance to improve weld quality and safety.
Torch Valve. A control device on a welding or cutting torch used to regulate gas flow. OSHA mandates proper torch valve operation and leak checks to prevent gas leaks and fire hazards.
Transverse Crack. A weld defect that runs perpendicular to the weld axis, often caused by high residual stress or poor weld design. OSHA welding codes require crack prevention techniques, such as preheating and stress relief treatments.
Travel Angle. The angle between the welding electrode, torch, or filler rod and the weld joint in the direction of movement. OSHA welding standards recommend optimal travel angles for different welding positions to ensure proper fusion and penetration.
Travel Speed. The rate at which the welding torch or electrode moves along the weld joint. Proper travel speed is essential for achieving good fusion and avoiding defects such as undercut or lack of penetration. OSHA welding standards require controlled travel speeds for high-quality welds.
Tungsten Electrode. A non-consumable electrode used in TIG welding, made from tungsten or tungsten alloys. OSHA requires proper tungsten electrode handling and grinding procedures to prevent contamination and exposure to hazardous particles.
Tungsten Inclusion. A weld defect caused by tungsten particles contaminating the weld metal, often due to improper electrode grinding or excessive current in TIG welding. OSHA welding inspection standards require non-destructive testing (NDT) methods to detect and remove tungsten inclusions.

U

Underbead Crack. A type of weld crack that forms in the heat-affected zone (HAZ) beneath the weld bead, often caused by hydrogen embrittlement, rapid cooling, or excessive residual stress. OSHA requires preheating and post-weld heat treatment in some materials to prevent underbead cracking.
Undercut. A weld defect in which the base metal is melted away at the edge of the weld but not filled with weld metal, leaving a groove that can weaken the joint. OSHA welding standards require proper electrode manipulation and heat control to prevent undercutting.
Undersized Weld. A weld that does not meet the minimum specified size or throat thickness, which can compromise the structural integrity of the joint. OSHA welding codes require welds to be inspected for proper size and strength to ensure safety.
Uphill Welding. A welding technique in which the weld progresses in an upward direction on a vertical surface, typically used for better penetration and stronger welds in thicker materials. OSHA welding standards specify technique requirements for different welding positions to ensure high-quality welds.
Uranium Welding. A specialized welding process used for joining uranium and uranium alloys, often requiring controlled environments to minimize oxidation and radiation hazards. OSHA mandates strict handling and shielding requirements when working with radioactive materials like uranium.
Ultrasonic Inspection (UT). A non-destructive testing (NDT) method that uses high-frequency sound waves to detect internal weld defects, such as cracks, voids, and incomplete fusion. OSHA requires ultrasonic testing in critical applications, such as pressure vessels and structural welds, to ensure weld integrity.
Ultimate Tensile Strength (UTS). The maximum stress that a welded joint or material can withstand before breaking under tension. OSHA welding standards require welds to meet specified tensile strength requirements to ensure structural integrity.
Ultraviolet Radiation (UV). A type of invisible radiation emitted during arc welding that can cause eye injuries (arc flash) and skin burns. OSHA requires welders to wear helmets with appropriate filter lenses and protective clothing to prevent exposure to UV radiation.
Unalloyed Steel. A type of steel that contains no significant alloying elements besides carbon and iron. OSHA welding standards specify preheating and electrode selection for unalloyed steels to prevent cracking and ensure weld quality.
Unstable Arc. A welding condition where the arc fluctuates unpredictably, causing inconsistent weld penetration and spatter. OSHA requires proper machine settings, electrode selection, and workpiece preparation to maintain arc stability.
Upset Welding. A resistance welding process in which pressure is applied to the workpieces before and during heating, causing plastic deformation and forming a weld. OSHA welding safety standards require proper machine settings and protective equipment for upset welding applications.
U-Tube Weld. A weld used to join U-shaped tubing, commonly found in heat exchangers and boiler components. OSHA mandates non-destructive testing and quality assurance measures for U-tube welds in high-pressure applications.

V

Vacuum Brazing. A brazing process conducted in a vacuum chamber to prevent oxidation and contamination. This method is commonly used in aerospace and electronics industries where high-quality, flux-free joints are required. OSHA requires proper training and handling procedures for vacuum brazing equipment to ensure worker safety.
Vacuum Welding. A welding process performed in a vacuum to eliminate oxidation and ensure high-purity welds. Common in semiconductor and aerospace applications, OSHA mandates the use of proper shielding and equipment maintenance when working with vacuum welding systems.
V-Groove Weld. A type of groove weld where the edges of the workpieces are beveled to form a V shape. This allows for better weld penetration and is commonly used in structural and pipe welding. OSHA welding standards require proper preparation and heat control for V-groove welds to prevent defects.
Ventilation. The process of ensuring adequate airflow to remove welding fumes, gases, and particulates from the workspace. OSHA mandates proper ventilation systems, including local exhaust ventilation (LEV), to protect welders from exposure to hazardous airborne contaminants.
Vertical Down Welding. A welding technique in which the weld progresses downward on a vertical joint. This method is commonly used for speed but requires careful control to prevent slag inclusion and lack of fusion. OSHA welding codes specify proper techniques to ensure structural integrity.
Vertical Position Welding. A welding position in which the weld axis is vertical. It includes both vertical up and vertical down techniques. OSHA classifies welding positions to ensure standardization in welding procedures and safety.
Vertical Up Welding. A welding technique in which the weld progresses upward on a vertical joint. This method provides better penetration and strength compared to vertical down welding. OSHA welding standards require controlled heat input to avoid excessive spatter and incomplete fusion.
Voltage. The electrical potential difference that drives current through a welding circuit. In welding, voltage settings affect arc stability, penetration, and bead profile. OSHA requires proper voltage control and insulation to prevent electrical hazards.
Voltage Drop. The reduction in voltage between the welding power source and the electrode due to resistance in the welding leads or connections. Excessive voltage drop can lead to poor arc performance. OSHA requires proper cable sizing and maintenance to minimize voltage drop and ensure safe welding operations.
Voltage Range. The acceptable limits of voltage for a specific welding process or material. Maintaining voltage within the recommended range ensures a stable arc and quality welds. OSHA requires welders to follow manufacturer specifications for voltage settings to ensure consistent weld quality.

W

Weaving. A welding technique in which the electrode or torch is moved side-to-side in a controlled motion to create a wider weld bead and improve fusion. OSHA requires proper weaving techniques to prevent defects such as undercut and incomplete fusion.
Weaving Bead. A weld bead created using a weaving motion, often used for filling large gaps or increasing deposition rate. OSHA welding standards ensure weaving bead control to prevent excessive heat input and distortion.
Weld Bead. The deposited molten filler metal that forms a single pass weld. OSHA welding standards require weld beads to have proper size, shape, and penetration to ensure joint strength.
Weld Crack. A defect in a weld that can occur due to excessive stress, cooling shrinkage, or contamination. OSHA requires thorough weld inspections to detect and repair cracks before service.
Weld Defect. Any imperfection in a weld that reduces its strength, quality, or performance. OSHA welding codes classify defects such as porosity, undercut, and incomplete fusion and require proper corrective actions.
Weld Distortion. The warping or misalignment of a metal workpiece due to heat-induced expansion and contraction during welding. OSHA welding procedures recommend controlled heat input and preheating to minimize distortion.
Weld Inspection. The process of evaluating a weld for defects, strength, and compliance with welding codes. OSHA requires non-destructive testing (NDT) methods, such as visual, ultrasonic, and radiographic inspections, for critical welds.
Weld Metal. The portion of the weld consisting of molten and solidified filler metal. OSHA welding codes specify weld metal properties to ensure durability and resistance to cracking.
Weld Overlay. A process in which additional layers of weld metal are deposited onto a surface to improve corrosion resistance or wear resistance. OSHA welding standards require proper shielding gas and filler metal selection for overlay applications.
Weld Pass. A single progression of welding along a joint or weld bead. Multiple weld passes may be required for thicker materials. OSHA welding codes define procedures for multi-pass welding to ensure proper fusion and joint strength.
Weld Pool. The localized area of molten metal created during welding. OSHA welding standards emphasize control of the weld pool to ensure complete fusion and prevent defects.
Weld Procedure Specification (WPS). A documented set of welding instructions that outlines materials, techniques, and parameters required for a specific welding job. OSHA requires WPS compliance in regulated industries to ensure weld quality and safety.
Weld Puddle. Another term for the weld pool, referring to the molten metal formed during welding. OSHA requires welders to control heat input to prevent defects such as porosity and cracking.
Weld Reinforcement. The excess weld metal that extends beyond the joint surface. While reinforcement adds strength, excessive reinforcement can lead to stress concentrations. OSHA welding codes specify acceptable reinforcement limits.
Weld Root. The bottom part of a weld joint, where fusion between the base metals begins. OSHA requires proper penetration at the weld root to prevent root cracks and lack of fusion.
Weld Seam. The continuous line where two materials are joined by welding. OSHA welding codes define requirements for seam welds to ensure structural integrity in applications such as pipelines and pressure vessels.
Weld Symbol. A standardized symbol used in blueprints to indicate weld type, size, and location. OSHA welding standards require welders to understand and follow weld symbols for compliance with design specifications.
Weld Toe. The edge of a weld bead where it meets the base metal. OSHA welding standards require smooth weld toes to prevent stress concentrations that can lead to cracking.
Weldability. The ability of a metal to be welded without forming defects. OSHA welding guidelines require the use of preheating, filler material selection, and proper techniques to improve weldability.
Welding Arc. The sustained electrical discharge between the electrode and workpiece that generates the heat needed for welding. OSHA requires welders to wear appropriate PPE to protect against arc radiation and burns.
Welding Fume. Airborne particles generated by the welding process, which can contain hazardous metals such as chromium and manganese. OSHA mandates proper fume extraction and respiratory protection to limit exposure.
Wire Feed Speed. The rate at which the electrode wire is fed into the weld in MIG and flux-cored welding. OSHA requires proper wire feed speed settings to ensure quality welds and prevent defects such as burn-through and lack of fusion.
Work Lead. The cable that connects the welding power source to the workpiece, completing the electrical circuit. OSHA requires proper grounding of the work lead to prevent electrical hazards.

X

X-Ray Inspection. A non-destructive testing (NDT) method that uses X-rays to examine the internal structure of a weld for defects such as porosity, cracks, or incomplete fusion. OSHA requires proper shielding and safety measures when using X-ray inspection to protect workers from radiation exposure.
X-Pattern Welding. A welding technique where weld beads are applied in an "X" shape to improve strength and minimize distortion. OSHA recommends controlled heat input to avoid warping and residual stresses in welded structures.
Xenon Arc Testing. A laboratory test that uses a xenon arc lamp to simulate sunlight exposure and assess the durability of welded materials and coatings. While not directly regulated by OSHA, material durability testing is essential in industries requiring long-lasting weld performance.
X-Groove Weld. A type of groove weld in which the edges of the base metal are beveled to form an "X" shape when viewed in cross-section. This joint preparation is used in thick metal welding to ensure full penetration. OSHA welding codes define joint design specifications to achieve strong and defect-free welds.
X-Weld Symbol. A welding symbol used in blueprints to indicate a weld applied at the intersection of two perpendicular surfaces. OSHA requires welders to understand and follow welding symbols to ensure proper joint preparation and execution.

Y

Yield Point. The stress level at which a metal begins to deform permanently under an applied load. In welding, understanding the yield point is essential for selecting materials that can withstand stress without failure. OSHA welding codes specify yield strength requirements for structural components to ensure safety.
Yield Strength. The maximum stress a material can withstand before it starts to permanently deform. In welding applications, yield strength determines the ability of a welded joint to resist forces without bending or breaking. OSHA requires that welded structures meet specific yield strength standards to ensure durability and safety.
Yoke. A U-shaped or magnetic device used in non-destructive testing (NDT), such as magnetic particle inspection, to detect surface and subsurface cracks in welded joints. OSHA requires proper inspection techniques to identify welding defects that could compromise structural integrity.

Z

Zero Defect Welding. A quality control approach in welding that aims to produce welds with no defects, such as cracks, porosity, or incomplete fusion. OSHA welding standards emphasize thorough inspection and testing to achieve high-quality welds with minimal defects.
Zero Gap. A welding joint configuration where no gap exists between the two workpieces being joined. OSHA welding procedures specify appropriate joint preparation techniques to ensure complete fusion and structural integrity.
Zinc Coating. A protective layer of zinc applied to steel (such as galvanized steel) to prevent corrosion. Welding zinc-coated materials can produce hazardous fumes, so OSHA requires proper ventilation and respiratory protection to prevent metal fume fever.
Zinc Fume Fever. A temporary illness caused by inhaling zinc oxide fumes, commonly produced when welding galvanized steel. Symptoms include chills, fever, nausea, and muscle pain. OSHA mandates proper fume extraction and respiratory protection to prevent zinc fume fever.
Zone of Thermal Influence. Also known as the heat-affected zone (HAZ), this is the area surrounding a weld that experiences changes in microstructure and mechanical properties due to welding heat. OSHA welding standards require careful control of heat input to minimize weakening of the base metal.
Z-Toughness. A measure of a metal's resistance to lamellar tearing, particularly in thick steel plates used for structural welding. OSHA welding standards require material testing to ensure adequate toughness in applications with high stress or impact loads.