Welding Engineering

welding banner 3Welding is the fabrication process that fuses like materials togeather by heating them to a suitable temperatures, this can be acomplished by brazing, soldering or welding.  The filler metal has a melting point approximately the same or below that of the metals being joined togeather.  Welding is done by melting like metals then add a filler material to the joint, once cooled forming a sturdy joint.  Brazing and soldering is the melting of a filler material that is pulled into the gap between materials joining them togeather.  The brazing filler has a melting point below the materials being joind togeather.

There are many different types of welds, techniques, designs, codes and procedures.

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Welding Engineering Index


Welding Process

  • Arc Welding  -  A group of welding processes used to weld metal using heat of an electric arc, with or without filler material.
    • Carbon Arc Welding  -  A process with an electric arc is struck between a carbon electrode and the work piece.
    • Flux Cored Arc Welding  -  This process has a constantly fed electrode that becomes part of the weld.  The flux cored electrode is a composit tubular filler metal surounded with a core of mineral compounds and powdered metals.
    • Gas Metal Arc Welding  -  Also called MIG (metal inert gas) welding.  This process has a constantly fed electrode that becomes part of the weld.  Also a seperate tank adds inert gas to the arc in order to ensure that oxidation does not occur during the menting process.
    • Gas Tungsten Arc Welding  -  Also called TIG welding and heliarc welding.  The arc is created between a non-consumable tungsten electrode and the workpiece.
    • Plasma Arc Welding  -  The arc is created between a non-consumable tungsten electrode and the workpiece.  Plasma gas, usually argon, is added between the electrode and the nozzle.
    • Shielded Metal Arc Welding  -  Also called stick welding.  Is one of the older arc welding method by heating with an arc between a flux covered electrode (filler material) that melts to form a weld pool, which cools and joins the two to metals.
    • Submerged Arc Welding  -  This type of weld is usually used on thick steel with longer welds.  It is created by submerging the electric arc beneath a layer of powdered flux.
  • Oxy-fuel Gas Welding  -  A group of welding processes used to weld metal using heat from a combination of oxygen and a fuel gas.
    • Air-acetylene Welding  -  Uses air-aceetylene flame without the application of pressure.  Not used very often. 
    • Oxy-acetylene Welding  -  Uses acetylene as a fuel gas.
    • Oxy-propane Welding  -  Uses propane as a fuel gas.
    • Oxy-hydrogen Welding  -  Uses hydrogen as a fuel gas.
    • Pressure Gas Welding  -  Makes a weld simultaneously over the entire surface.  This is done with pressure and without filler material.
  • Resistance Welding  -  A group of welding processes used to weld metal using electric current to force join by pressure of the metals.  The current passed through and heats the metals until they begin to melt at the spot where they are in contact.
    • Resistance Flash Welding  -  Also called butt welding.  The work pieces act as an electrode and the entire cross-section gap is welded.  Two secured work pieces are placed close togeather and a current is applied.  The current creates an arc between the two work pieces, melting both togeather.
    • Resistance Projection Welding  -  The curent is focused from electrode to electrode through the tip of the projection.  This concentrates on specific raised sections or projections of a work piece.  The weld current and force can be forcused into a small area of the projection to produce heat at a specific spot.  During the process the projection collapses making it impossible for further welding since the large surface of the electrode diffuses under current density.
    • Resistance Spot Welding  -  The curent is focused from electrode to electrode and disperced between the two.  Two operlapping work pieces are placed togeather creating a surface between the two.  An electrode is placed on each side of the work piece across from each other.  An electric charge between the two electrodes melts the two pieces togeather from the center out.
    • Resistance Seam Welding  -  The electroces are two copper wheels constantly applying force to the work piece, each rooling on opposite sides of the materials.  The electric charge can be applied in spurts or at a constant feed.
  • Solid-state Welding  -  A group of welding processes used to weld metal by requiring a temperatures below the melting point of the base metal being joined, without the addition of brazing filter metal.
    • Coextrusion Welding  -  Dissimilar metals are extruded through the same die.
    • Cold Pressure Welding  -  A pressure is applied at room temperature to cause compress and bond the materials togeather.  This process has no heat or flux and one of the materials must be highly ductile.
    • Diffusion Welding  -  Uses heat and pressure in a controlled atmosphere, with enough time for diffusion and coalescence to happen.
    • Explosion Welding  -  Also called explosive cladding.  Combines two metals togeather with an explosive force causing enough energy to form a metallic bond.   
    • Forge Welding  -  The workpieces are heated to the welding temperature and hamered togeather to make the weld.
    • Friction Welding  -  The compressive force contact of workpieces rotating or moving relative to one another to produce heat from the faying surfaces.
    • Friction Stir Welding  -  A rapidly rotating tool traversing a joint between two metals creating friction heating and plastic material displacement welding the seam togeather.
    • Hot Pressure Welding  -  Metals are pressed togeather at elevated temperatures below the melting point in a vacuum or an inert gas atmosphere.
    • Hot Isostatic Pressure Welding  -  A hot inert gas applies pressure inside a pressure vessel.
    • Magnetic Pulse Welding  -  Short electromagnetic pulses produce a high-density magnetic field in the workpiece.  This causes plastic deformation along the workpiece and the two pieces to share electrons at the atomic level.
    • Roll Welding  -  Also called roll bonding is a cold welding process.  Two or more metals are fed through a cold rolling mill under enough pressure to compress and bond the materials togeather.
    • Ultrasonic Welding  -  Two workpieces are held togeather, the oscillatory shear stresses of ultrasonic frequency causes coalescence or welding.


Welding Safety Procedures

Welding is safe when sufficient measures are taken to protect the welder from potential hazards.  When these measures are overlooked or ignored, welders can encounter such dangers as electric shock, overexposure to radiation, fumes and gases, fire, or explosion, any of which can result in fatal injuries.

  • Shop staff approval is required before using any welding equipment.
  • Welders, assistants, and anyone else in the welding area shall wear glasses or shields of recommended shades during welding operations.
  • The welder is responsible for erecting a screen around the welding area to protect other personnel in the shop from eye injury.
  • Inspect all welding equipment to be used, prior to each use, for possible damage.
  • Avoid handling oxygen bottles with greasy hands, gloves or rags.  Fatal explosions have resulted from this cause.
  • Always strap tanks to a welding cart or a fixed object.  Never allow a gas cylinder to be free standing.  Replace the safety cap on all cylinders when not in use.
  • When arc welding, make sure work and/or work table is properly grounded.
  • Do not arc weld in a wet area.
  • Be alert to possible fire hazards.  Move the object to be welded to a safe location, or, remove all flammable materials from the work area.
  • Never weld in the same area where degreasing or other cleaning operations are performed.
  • Keep suitable fire extinguishing equipment nearby and know how to operate it.
  • Shut off the cylinder valves when the job is completed, release pressure from the regulators by opening the torch valves momentarily, and back out regulator adjusting valves.  Never leave the torch unattended with pressure in the hoses.
  • Utilize all protective equipment and clothing.  Do not arc weld with any part of the body uncovered, the arc light is actinic light (excessive ultraviolet) and will cause burns similar to severe sunburn.
  • Never weld inside drums or enclosed spaces without adequate ventilation, or, the use of airline respirators or self contained breathing apparatus.
  • Check the ventilation system before starting to weld and periodically thereafter to insure adequate performance.  Welding fumes should not be allowed to get into the rest of the shop working areas.
  • Never cut or weld any container that has held explosive or flammable materials. Use prescribed methods for cleaning or flooding.
  • Never use wrenches or tools except those provided or approved by the gas cylinder manufacturer to open valves.  Never use a hammer to open or close valves.
  • Abide by any other safety measures required for each particular type of welding.
  • Allow for proper ventilation when brazing or soldering.  The fluxes are acidic and toxic.
  • Do not weld on painted, galvanized or greasy, oily metals. Not only can the fumes be toxic, but the welds will not be satisfactory and will fail in use.


Welding Engineering Standards

ISO Standards

  • ISO 693 - Dimensions of seam welding wheel blanks
  • ISO 4850 - Personal eye-protectors for welding and related techniques -- Filters -- Utilisation and transmittance requirements
  • ISO 7286 - Graphical symbols for resistance welding equipment
  • ISO 8167 - Projections for resistance welding
  • ISO 15607 - Specification and qualification of welding procedures for metallic materials -- General rules
  • ISO 17846 - Welding and allied processes -- Health and safety -- Wordless precautionary labels for equipment and consumables used in arc welding and cuttin


Welding Abbreviations

  • Above Grade (AG)
  • Above Ground (AG)
  • Alternating Current (AC)
  • Aluminium (AL)
  • Amperes (AMP)
  • Argon (Ar)
  • Below Grade (BG)
  • Bottom (BOT)
  • Bottom of Concrete (BOC)
  • Bottom of Pipe (BOP)
  • Bottom of Steel (BOS)
  • Brazing (BZ)
  • Carbon Dioxide (\(CO_2\))
  • Center (CTR)
  • Center to Center (C-C)
  • Contact Tip to Work Distance (CTWD)
  • Constant Current (CC)
  • Constant Voltage (CV)
  • Direct Current (DC)
  • Direct Current Electrode Negative Polarity (DCEN)
  • Direct Current Electrode Positive Polarity  (DCEP)
  • Electrical Stick Out (ESO)
  • Face to Face (F-F)
  • Flat on Top (FOT)
  • Forged Steel (FST)
  • Foundation (FND)
  • Ground (GN)
  • Heat Affected Zone (HAZ)
  • Helium (He)
  • Induction Soldering (IS)
  • Inter Pass Temperature (IPT)
  • Laser Beam (LB)
  • Magnetic Practice Testing (MT)
  • Metal Active Gas (MAG)
  • Metal Inert Gas (MIG)
  • Optical  Emision Spectroscrope (OES)
  • Oxygen (\(O_2\))
  • Post Weld Heat Treatment (PWHT)
  • Radiographic Testing (X-ray)
  • Resistance Soldering (RS)
  • Top of Concrete (TOC)
  • Top of Pipe (TOP)
  • Top of Steel (TOS)
  • Torch Soldering (TS)
  • Travel Speed (TS)
  • Tungsten Inert Gas (TIG)
  • Ultrasonic Testing (UT)
  • Welding Procedure Specification (WPS)
  • Wire Feed Speed (WSF)
  • X-ray Fluorescence Spectroscrope (XRF)
  • X-ray Photoelectric Spectroscrope (XPS)


Welding Process Abbreviations

  • Air-acetylene Welding (AAW)
  • Arc Welding (AW)
  • Carbon Arc Welding (CAW)
  • Coextrusion Welding (CEW)
  • Cold Pressure Welding (CPW)
  • Diffusion Welding (DFW)
  • Explosion Welding (EXW)
  • Flux Cored Arc Welding (FCAW)
  • Forge Welding (FOW)
  • Friction Welding (FRW)
  • Friction Stir Welding (FSW)
  • Gas Metal Arc Welding (GMAW)
  • Gas Tungsten Arc Welding (GTAW)
  • Hot Pressure Welding (HPW)
  • Hot Isostatic Pressure Welding (HIPW)
  • Magnetic Pulse Welding (MPW)
  • Oxy-acetylene Welding (OAW)
  • Oxy-fuel Gas Welding (OFW)
  • Oxy-hydrogen Welding (OHW)
  • Oxy-propane Welding (OPW)
  • Plasma Arc Welding (PAW)
  • Pressure Gas Welding (PSW)
  • Resistance Welding (RW)
  • Resistance Flash Welding (RFW)
  • Resistance Projection Welding (RPW)
  • Resistance Spot Welding (RSW)
  • Resistance Seam Welding (RESW)
  • Roll Welding (ROW)
  • Shielded Metal Arc Welding (SMAW)
  • Solid-state Welding (SSW)
  • Submerged Arc Welding (SAW)
  • Ultrasonic Welding (USW


Tags: Abbreviations Nomenclature and Symbols

Welding Engineering GlossaRy


  • Aging  -   The term origionally applied to the process or sometimes to the effect of allowing a metal to remain at ordinary temperatures.
  • Alclad  -   The common name for a type of clad wrought aluminum product with coatings of high purity aluminum or an aluminum alloy different from the core alloy in composition.
  • Alloy  -  A metallic substance consisting of two or more elements, of which at least one is a metal, and in which all elements are miscible in the molten state, and which do not separate when solid.
  • Alloying Elements  -  Chemical elements constituting an alloy.  In steel, usually the elements added to modify the properties of the steel.
  • Annealing  -   A heating and controlled cooling operation to impart specific desirable properties generally concerned with subsequent fabrication of the alloy.
  • Applied Force  -  Can come from different types of forces, one of them could be Newton's Second Law.  There really is no one formula.
  • Arc  -  A gap between the end of the electrode and the base metal.
  • Arc Eye  -  A burn on the exterior surface of the operators eye, due to its exposure to an open arc.
  • Arc Gap  -  See arc length
  • Arc Length  -  The distance between the material and the electrode tip.
  • Arc Strike  -  Arc strike is an arc initiated (accidental or intentional) on the base metal surface away from the weld zone.
  • Arc Time  -  How long a welder can weld without any problems per 8 hours.
  • Arc Voltage  - The voltage across the welding arc.
  • Arc Welding  -  See welding processes
  • Area  -  The square units of a given plane.
  • Austenite  -  A solid solutionin which gamma iron is solvent, having a face-centered cubic crystal structure.
  • Austenite Steel  -  Steel, which due to its composition has a stable structure at normal (room) temperature.
  • Automatic Welding  -  Permits the operation without adjustment of controls by an operator.
  • Axial Force  -  The force acting parallel to the longitudinal x-axis.


  • Back Weld  -  A weld at the back of a groove weld.
  • Backhand Welding  -  A technique in which the welding tourch or gun is directed opposite to the process welding.
  • Backing Ring  -  Is inserted between two butt welding joints before welding to allow for complete penetration.
  • Base Metal  -  A part that all other parts are being brazed, cut, soldered, or welded to.
  • Bead Weld  -  A type of weld having one or more string beads delivered on any surface.
  • Bend Allowance  -  The length of the arc through the bend area at the neutral axis.
  • Bend Angle  -  The included angle of the arc formed by the bending operation.
  • Bend Compensation  -  The amount by which the material is stretched or compressed by a bend operation.  All stretch or compression is assumed to occure in the bend area.
  • Bend Deduction  -  The amount of material needed to be removed to achieve the correct length.
  • Bend Lines  -  The straight lines on the inside and outside surfaces of the material where the flange boundary meets the bend area.
  • Bending Stress  -  Is when a beam is subjected to a load along it's length axis with stress applied perpendicular to the axis.
  • Bent Test  -  A test commonly used to determine relative ductility of a sample by bending it over a given radius through a given angle.
  • Bevel  -  An angle edge cut or ground.
  • Blind Joint  -  A joint where no portion of which is visible.
  • Blow Hole  -  Formed due to the gas in the liquid metal and the weld can not escape when metal puddles solidify.
  • Blue Brittleness  -  Brittleness exhibited by some steels after being heated to a temperature within the range of about 400F to 700F (200C to 370C), particularly if the steel is worked at the elevated temperature.
  • Bond  -  The junction of the weld metal and the base metal.
  • Brass  -  A copper-base alloy in which zinc is the principle added element.
  • Brazing  -  The brazing filler metal melts at a temperature having a liquid above 450 deg C and always below the base metal being joined.
  • Brinell Hardness Number  -  Is a value assigned to the hardness of metals and alloys.
  • Brittleness  -  A tendency to fracture without appreciable deformation.
  • Burr  -  A sharp thin ridge of roughness left after cutting.
  • Butt Joint  -  Joining two metals aligned approximately of lying on the same plane.
  • Butt Joint Types  -  bevel-groove, flare-bevel-groove, flare-V-groove, J-groove, square-groove, U-groove, and V-groove.
  • Buttweld  -  A weld at the butt joint.


  • Carbon Electrode  -  A non-filter metal electrode used in arc welding or cutting, consisting of a carbon or graphite rod, which may be coated with copper or other coatings.
  • Carbon Steel  -  A metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties.
  • Case Hardning  -  Adding carbon to the surface of a mild steel object and heat treating to produce a hard surface.
  • Cold Working  -  The permanent crystal distortion of a metal below its lowest temperature of re-crystallization.
  • Combustion  -  A reaction called rapid oxidation or burning produced with the right combination of a fuel, oxygen, and heat.
  • Complete Joint Penetration (CJP)  -  Weld completely fills the gap between the two pieces.
  • Composite Electrode  -  Multi component filter metal electrodes in various physical forms such a standard wires, tubes and covered wires.
  • Continuous Weld -  A weld that extends continuously from one end of a joint to the other.
  • Corner Joint Types  -  bevel-groove, corner-flange, edge, fillet, flair-V-groove, J-groove, spot, square-groove or butt, U-groove, and V-groove.
  • Corrosion  -  The thinning of a pipe wall that is typically caused by a chemical reaction from a corroding fluid or agent and is limited almost exclusively to metal products. 
  • Cover Pass  -  The final pass of the weld that forms the face.
  • Cover Plate  -  Used for eye protection.  A removable pane of colourless glass, plastic coated glass or plastic that covers the filter plate and protects it from weld splatter, pitting or scratching when used in a helmet, hood or goggles.
  • Covered Electrode  -  An electrode consisting of a core of a bare electrode or metal cored electrode to which a covering, sufficient to provide a slag layer on the weld metal, has been applied.
  • Crater  -  A depression at the termination of a weld bead.
  • Current  -  The rate of flow of electricity flowing past a point in a conductor every second.


  • Decarburizing Flame  -  A flame which removes carbon from the molten metal.
  • Defective Weld  -  A weld having one or more defects.
  • Density  -  The ratio of the amount of matter in an object compared to its volume.
  • Deposition Efficiency  -  Ratio of the weight of deposited metal to the net weight of the filter metal consumed.  Arch welding.
  • Depth of Fusion  -  Distance the fusion extends into the base metal or previous pass from the surface melted during welding.


  • Edge Joint  -  Joining the edges of two or more parallel workpieces.
  • Edge Joint Types  -  bevel-groove, corner-flange, edge-flange, J-groove, square-groove, U-groove, and V-groove.
  • Elastic Modulus  -  The ratio of the stress applied to a body or substance to the resulting strain within the elastic limits.
  • Elastic Potential Energy  -  The energy stored in objects as the result of deformation, such as a spring when stretching or compressing.
  • Electrode  -  Conducts current through, creating an arc through the tip of the electrode to the metal.  The electrode is a coated metal wire made with a composit material similar to the material being welded.  See stick electrode and MIG electrode.
  • Electrode Force  -  The force between electrodes in a spot, seam, and projection weld.
  • Electrode Lead  -  The electrical conductor between the source of arc welding current and the electrode holder.
  • Electrode Reaction  -  Interfacial reaction equivalent to the transfer of change between electronic and ionic conductors.
  • Emissive Electrode  -  A filter metal electrode consisting of a core of a bare electrode or a composite electrode to which a very light coating has been applied to produce to a stable arc.


  • Face  -  The outer most portion of the weld or the final pass of a multi-pass weld from the weld face.
  • Face Shield  -  Used for eye protection.  A device positioned in front of the eyes and over all or a portion of the face to protect the eyes and face.
  • Faying Surfaces  -  Contacting surfaces of faces of two similar or dissimilar materials placed in tightcontact ot form a joint.
  • Field Weld  -  A weld made at a location other than the shop or place of construction.
  • Filler Material  -  A metal added to make a joint.
  • Fish Eye  -  A discontinuity found on the fracture surface of a weld in steel.
  • Flux  -  A chemical compound to hender or stop the formation of oxides and other substances in the moltent metal.
  • Flux Cored Electrode  -  A composite hollow filler metal electrode containing within it ingredients to provide such functions as shielding atmosphere, deoxidation, arc stabilization and slag formation.
  • Force  -  The push or pull of an object resulting in a change from rest or motion.
  • Forehand Welding  -  A technique in which the welding torch or gun is directed toward the process of welding.
  • Full Penetration (FP)  -  Weld completely fills the gap between the two pieces. 
  • Fume  -  Solid particles formed when a solid vaporizes once and then condenses throught rapid cooling.
  • Fusion  -  The melting togeather of the filler material and base metal or only the base metal.
  • Fusion Face  -  The surface of the base metal that is melted during welding.
  • Fusion Welding  -  Amy type of welding process that uses fusion.
  • Fusion Zone  -  Area of base metal melting as determined on the cross-section of a weld.


  • Gas Welding  -  See solid-state welding processes
  • Gouging  -  The forming of a bevel or groove by material removal.
  • Groove  -  A channel or opening created between the surface of the weld joint before welding to achieve necessary penetration.
  • Grove Angle  -  The inclined angle between the weld channel or grove face.
  • Grove Face  -  Any surface in a weld channel or groove before welding.
  • Groove Radius  -  The radius used to form the shape J or U groove weld joint.
  • Groove Weld  -  A weld made in a channel or opening between two workpieces.
  • Groove Weld Types  -  double-bevel-groove, double-flare-bevel-groove, double-flare-V-grove, double-J-groove, double-U-groove, double-V-groove, single-bevel-groove, single-flare-bevel-groove, single-flare-V-groove, single-J-groove, single-U-groove, single-V-groove, square-groove
  • Ground Connection  -  A safety connection from the welding machine to the earth.
  • Ground Lead  -  A connection from the welding machine to the work.


  • Hand Shield  -  A protective device, used in arc welding, for shielding the eyes, face and neck.
  • Hardfacing  -  A surfacing material added to the surface of impliments/objects to reduce wear from cracking, erosion, impact, and etc.
  • Hardness  -  The property of a material that enables it to resist plastic deformation, usually by penetration.
  • Heat  -  A form of energy that causes physical change in what is being heated.
  • Heat Affected Zone  -  The portion of the base metal that has not been melted, but whose mechanical properties or microstructure have been altered by the heat of welding, brazing, soldering or cutting.
  • Helmet  -  Used for eye protection.  A device designed to be worn on the head to protect the eyes, face and neck from arc radiation, radiated heat, splatter, or other harmfull matter expelled during arc welding.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
  • Heat Capacity  -  The ratio of heat transferred to raise the temperature of an object.
  • Heat Input  -  The measure of energy that is supplied to the material to form a weld.
  • Heat Transfer  -  The exertion of power that is created by heat, or the increase in temperature.
  • Heat Transfer by Conduction  -  It is the flow of energy between two objects, or within one object, where there is a temperature differential.
  • Heat Treatment  -  The heating and cooling of metals or alloys.
  • Hot Cracks (solidification cracks)  -  Develops in high temperatures (over 1200 °C) as the weld solidifies or right after.  The most common type is a longitudinal crack on the centerline of the weld. It can appear on the weld’s surface or just below, either as a separate crack or starting from acrater crack.
  • Hot Pass  -  A second pass in a multi-pass joint.
  • Hot Work Permit  -  The employer's written authorization to perform operations (for example, riveting, welding, cutting, burning, and heating) capable of providing a source of ignition.


  • Incomplete Fusion  -  A weld break where complete fusion did not occur between the weld material and the faces or adjoining weld material. It is usually caused by improper handling of the welding electrode, inadequate groove preparation, mill scale or poor interpass cleaning.
  • Incomplete Penetration  -  A root condition in a groove weld where the weld metal doesn't totally extend through the joint thickness. This can be because of improper manipulation of the electrode, poor groove preparation or excessive contamination.
  • Incomplete Weld  -  A defect in the solder joint that causes cracks or damage to the bond.
  • Inductance  -  The measure of an electric conductor or circuit by which an electromotive force is induced in it.
  • Inert Gas  -  A gas which does not normally combine chemically with the base metal or filler metal.
  • Inside Bend Radius  -  The radius of the arc on the inside surface of the bend area.
  • Integranulat Corrosion  -  Usally of stainless steals or certain nickle-base alloys, that occures as the result of sensitization in the heat affected zone during the welding process.
  • Intermittent Weld  -  A weld in which the continuity is broken by recurring unwelded spaces.


  • Joint  -  The junction of members or the edge of members that are joined or to be joined.
  • Joint Penetration  -  The minimum a groove weld extends from its face into a joint.
    • Complete Joint Penetration (CJP)  -  Weld completely fills the gap between the two pieces.
    • Partial Joint Penetration (PJP)  -  Weld fills a portion of the gap between the two pieces.
  • Joint types  - 
    • Butt Joint  -  When two plates are butted togeather.
    • Corner Joint  -  When two plates are butted togeather creating a L.
    • Edge Joint  -  When two plate edges are butted togeather.
    • Lap Joint  -  When two flat surfaces overlap each other.
    • Tee Joint  -  When two plates are butted togeather creating a T.
  • Joule’s Law  -  The amount of heat (energy) delivered to something.


  • K-factor  -  The distance from the inside bend to the neutral axis.  The neutral axis is where the material is neither compressed or stretched.
  • Kinetic Energy  -  The energy in moving objects or mass.  If it moves, it has kinetic energy.


  • Lap Joint Types  -  bevel-groove, flare-bevel-groove, J-groove, plug, slot, and spot.
  • Liquidus  -  The lowest temperature at which a metal or alloy is completely liquid.


  • Manual Welding  -  The entire welding process is performed and controlled by hand.
  • Mass  -  The amount of matter an object has.
  • Matching Weld Metal  -  The electrode strength, both yield and tensile strength, is similar to the strength of the base metal.
  • Machining Metal Removal  -
  • Machining Surface Feet per Minute  -
  • Materials  -  The matter an object is made of.
  • Material Hardness  -  The property of a material that enables it to resist plastic deformation, usually by penetration.
  • Maximum Fillet Weld Size  -  There is no size restrictions to a fillet weld.  But if the weld is greater than 1/2" it will take a larger amount of heat to be put into the connection.  Preheating will allow for more even cooling which could help prevent distortion and weld cracking.
  • Metal Removal Rate  -  The volume of chips material removed in one minute.
  • Melt-thru  -  Complete penetration of a joint weld from one side.
  • Melting Point  -  A solid is the temperature at which it changes state from solid to liquid.
  • Melting Range  -  The temperature range between solidus and liquidus of a weld.
  • Melting Rate  -  The weight or length of electrode melted in unit time.
  • Metal Cored Electrode  -  A composite filler metal electrode consisting of a metal tube or other hollow configuration containing alloying ingredients.
  • Metal Electrode  -  A filter or non-filler wire or rod, either bare or covered, used in an arc welding or cutting.
  • MIG Electrode  -  A constantly fed electrode that becomes part of the weld.
  • MIG Welding  -  Also called gas metal arc welding.
  • Minimum Fillet Weld Length  -  When only longitudinal welds are used for connection of bars and plates, their length may not be less than the distance between them.
  • Mold Lines  -  For bends of less than 180 degrees, the mold lines are the straight lines where the surfaces of the flange bounding the bend area intersect.


  • Neutral Axis  -  Looking at the cross-section of the bend, the neutral axes is the theoretical location at which the material is neither compressed nor stretched.
  • Neutral Flame  -  Is when oxygen and acetylene are mixed in equal porporttions.  See oxyfuel gas welding.
  • Non-ferrous  -  Contain no iron, is corrosion resistant, lighter in weight, malleability.


  • Overlap  -  Liquid metal surface is not melting on the weld.
  • Over Welding  -  Depositing more filler metal than required.
  • Oxidizing Flame  -  Is when an excess amount of oxygen is used.  See oxyfuel gas welding.
  • Oxyfuel Gas Welding  -  See welding processes


  • Partial Joint Penetration (PJP)  -  Weld fills a portion of the gap between the two pieces.
  • Partial Penetration (PP)  -  Weld fills a portion of the gap between the two pieces.
  • Pass  -  A single progression of a welding surfacing operation along a joint, weld deposit, or substrate.
  • Pickling  -  The chemical removal of surface oxides (scale) and other contaminants such as dirt from iron and steel by immersion in an aqueous acid solution.
  • Pickling Stain  -  Discoloration of metal due to chemical cleaning without adequate washing and drying.
  • Plug Weld  -  Joining two pieces of metal through a drilled hole or slot in the top piece which is laid over the bottom piece.
  • Porosity  -  Happens when a contaminent or gas is absorbed into the weld puddle.
  • Post Heating  -  The application of heat to an assembly after welding, brazing, soldering, thermal spraying ot thermal cutting.
  • Pre Heating  -  The application of heat to the base metal immediately before welding, brazing, soldering, thermal spraying ot thermal cutting.
  • Prandtl Number  -  In fluid dynamics, used to calculate force by the ratio of momentum diffusivity (kinematic viscosity) and thermal diffusivities.
  • Prequalified Welded Joints  -  The fabricator can use these joints with a prequalified procedure and not have to do any additional testing to insure weld joint soundness and strength.
  • Preheat  -  The application of heat to the base metal immediately before welding, brazing, soldering, cutting, or forming.
  • Process Qualification  -  The demonstration that welds or other work produced by a specified procedure can meet prescribed standards.
  • Puddle  -  A nonstandard term for weld pool.
  • Pure Gas  -  The replacement of air within a piping system with an inert gas.  May be required by the welding process.


  • Quenching  -  The fast cooling of metals or alloys for the process of hardening.  This process can be done with air, oil, or water.  If the metal cools too quickly due to a large flow of heat into the thick base plate, the weld may become brittle, having low fracture toughness.


  • Reducing Flame  -  Is when an excess amount of acetylene is used.  See oxyfuel gas welding.
  • Reinforcement  -  In branch connections, reinforcement is material around a branch opening that serves to strengthen it.
  • Residual Stress  -  Stress present in a member that is free to external forces or thermal gardients.
  • Resistance Welding (RW)  -  See welding processes
  • Reverse Ploority  -  The arrangement of direct current arc welding leads with the work as the negative pole and electrode as the positive pole of the welding arc.
  • Root  -  The narrowest point in the gap between the two work pieces to be welded or the point in the gap furthest from the electrode.
  • Root Opening  -  A seperation at the joint between the workpieces.
  • Root Pass  -  The first weld pass made into the root of the weld.
  • Root Penetration  -  The depth that a weld extends into the root of the joint.
  • Root Reinforcement  -  The opposite side from which the weld was done.
  • Root Surface  -  The exposed surface of a weld on the side other than that from which welding was done.
  • Running a Bead  -  The process of making a weld.


  • Seal Weld  -  A weld commonly used to stop leakage of gasses and liquids from containers and pipelines.
  • Seam Weld  -  A continous weld.
  • Second Moment of Area  -  The resistance of an object to bend around a certain axis of a cross-section area.
  • Set Back  -  For bends of less than 180 degrees,  the setback is the distance from the bend lines to the mold line.
  • Shear Carriage  -  Bottom section of the shear that rises when a cut is made and catches the pieces of scrap.  Located at the weld.
  • Shear Modulus  -  The ratio of the tangential force per unit area applied to a body or substance to the resulting tangential strain within the elastic limits.
  • Shear Stress  - Tends to deform the material by breaking rather than stretching without changing the volume by restraining the object.
  • Shielding Gas  -  A gas ueed to block out the atmosphere or contamination in order to prevent oxidization in the moltent well pool.
  • Shrinkage  -  The contractive force that an object undergoes as it cools.
  • Soldering  -  The solder filler metal melts at a temperature having a liquid below 450 deg C and uses a flux is to clean the metal suface allowing the solder to flow easy.
  • Solidus  -  The highest temperature at which a metal or alloy is completely solid.
  • Slag  -  A non-metallic substance that forms in the weld.
  • Slag Inclusion  -  It is introduced in the weld, between welds and the surface of the weld.
  • Slot Weld  -  When two workpieces are places togeather and one of them have a slot cut in it for access to weld.
  • Spacer Strip  -  A metal strip or bar prepared for a groove weld, and inserted in the root of a joint to serve as a backing and to maintain root opening during welding.
  • Spatter  -  Droplets of moltent metal over the surface near an arc weld.
  • Spatter Loss  -  Difference between the amount of electrode consumed and the amount of electrode deposited.
  • Stack Cutting  -  Thermal cutting of stacked metal plates arranged so that all the plates are severed by a single cut.
  • Stitch Weld  -  A short length of weld over and over.
  • Stick Electrode  -  A consumable electrode that becomes part of the weld.
  • Stick Welding  -  Also called shielded metal arc welding.
  • Straight Ploarity  -  The arrangement of direct current arc welding leads in which the work is the positive pole and the electrode is the negative pole of the welding arc.
  • Strain  -  The deformation, stretched or compressed, of a material compared to its original length.
  • Stress  -  The force per unit area of cross-section.
  • String Bead  -  A type of weld bead made without appreciable weaving motion.
  • Stringer Bead  -  A type of weld bead made without appreciable weaving motion.
  • Supplemential Steel  -  Structural members that frame between existing building framing steel members and are significantly smaller in size than the existing steel.
  • Surface Tension  -  The energy or force at the surface of a liquid that holds it together.
  • Surfacing  -  Adding one or more layers of material to a surface to get the desired dimension or properties.


  • Tack Weld  -  A weld made to hold parts in proper alignment until final welds are made.
  • Temper  -  The amount of hardness that an alloy has after cold working or heat treatment.
  • Tempering  -  A process of heating a normalized or quench-hardening steel to a temperature below the transformation range and then cooling at any rate desired.
  • Temperature  -  Normally described as the amount of heat or cold, but it is neither heat or cold.
  • Tensile Strength  -  The maximum stress a material can resist before it starts to elongate.
  • Tension  -  The force (pulling or stretching) acting on a material.
  • Tension Strength  -  The capacity of a material to resist a force tending to stretch it.
  • Thermal Conductivity  -  The ability to transfer heat within a material without any motion of the material.
  • Thermal Diffusivity  -  A measure of the transient thermal reaction of a material to a change in temperature.
  • Thermal Expansion  -  The increase in length, area or volume due to the increase (in some cased decrease) in temperature.
  • Thermal Resistance  -  Measures the temperature difference by which an object or material resists a heat flow.
  • Throat Area  -  Area of the weld.
  • Throat of a Fillet Weld (Actual)  -  The shortest distance from the root of a weld to its face.
  • Throat of a Tillet Weld (Theoretical)  -  The perpendicular distance from the beginning of the root of the joint to the hypotenuse of the largest right triangle that can be inscribed within the fillet weld cross section.
  • TIG Welding  -  Also called gas tungsten arc welding.
  • Toe of Weld  -  The junction between the face of a weld and the base metal.
  • Torch  -  A device used in gas tungsten arc welding (GTAW), also called TIG welding, to manage the position of the electrode.
  • Torsion  -  The stress of twisting of an object due to applied torque.
  • Tungsten Electrode  -  A nonconsumable electrode used in arc welding, consisting of a tungsten wire.


  • Ultimate Tensile Strength  -  Also called tensile strength or ultimate strength, is the maximum stress a material can resist before it starts to elongate.
  • Undercut  -  A groove melted into the base metal adjacent to the toe or root of a weld, and left unfilled by weld metal.  Can cause high stress and structural damage.
  • Underwater Welding  -  The process in which divers use shielded metal arc welding (SMAW or stick welding) to join metal, almost exclusively low carbon steels, underwater.
  • Under Welding  -  Depositing less filler material than required.


  • Vacuum  -  A contained space having little or no matter or a volume having a pressure lower than the outside atmospheric pressure.
  • Vacuum Melting  -  Melting in a vacuum to prevent contamination from air, as well as to remove gasses already dissolved in the metal.  The solidification may also be carried out in a vacuum or at low pressure.
  • Vapor Pressure  -  The pressure at a certain temperature when the liquid and vapor are in equilibrium.
  • Vertical Weld  -  The weld axis and force is approximately vertical.
  • Viscosity  -  The measure of the internal friction/resistance to the flow of a liquid.
  • Voltage  -  The amount of pressure that will cause one ampere of current in one ohm of resistance.
  • Volume  -  The space occupied by a mass.


  • Weld Bead  -  A weld created from one weld pass.
  • Weld Crack  -  Cracks can appear on the surface, inside the weld or heat effected zone.
  • Weld Decay  -  See integranulat corrosion
  • Weld Design Strength  -  AISC-13 Table J2.5 defines the resistance factors and nominal strengths for the base metal and weld metal for various type welds and loading conditions.  The orientation of the applied sterss with respect to the longitudal weld axis determines whether the weld is subject to tension, compression, or shear
  • Weld Face  -  The exposed surface of the weld on the side from which welding was done.
  • Weld Groove  -  The opening between two workpieces that provides a space to contain the welding metal.
  • Weld Joint Types  -  butt joint, corner joint, edge joint, lap joint, square joint, and tee joint.
    • Butt Joint Types  -  bevel-groove, flare-bevel-groove, flare-V-groove, J-groove, square-groove, U-groove, and V-groove.
    • Corner Joint Types  -  bevel-groove, corner-flange, edge, fillet, flair-V-groove, J-groove, spot, square-groove or butt, U-groove, and V-groove.
    • Edge Joint Types  -  bevel-groove, corner-flange, edge-flange, J-groove, square-groove, U-groove, and V-groove. 
    • Lap Joint Types  -  bevel-groove, flare-bevel-groove, J-groove, plug, slot, and spot.
  • Weld Meat  -  The portion of the weld that has been melted during welding.
  • Weld Meat Area  -  The area of the weld metal as measured on the cross-section of the weld.
  • Weld Metal  -  That portion of a weld that has been melted during welding.
  • Weld Nugget  -  The weld metal in spot, seam or projection welding.
  • Weld Pass  -  A single line of welding along a line leaving a bead or layer.
  • Weld Pool  -  A small body of moltent metal created by the arc of the tourch.
  • Weld Puddle (Weld Pool)  -
  • Weld Reinforcement  -  Weld metal in excess of the quantity required to fill a joint.
  • Weld Toe  -  Where the weld face meets the base metal.
  • Welder Certification  -  The act of determining, verifying, or attesting in wrighting that a welder is qualified to produce welds which can meet perscribed standards.
  • Welder Performance Qualification  -  Demonstration of a welder's ability to produce welds in a manner described in a welding procedure specification that meets prescribed standards.
  • Welding  -  Used to join most all metals whether thin or thick and suitable for high-temperature applications, producing a strong joint than brazing or soldering.
  • Welding Current  -  The current which flows through the electric welding circuit during the making of a weld.
  • Welding Defects  -  Blow hole, defect of joint shape, incomplete fusion, overlap, slag inclusion, undercut, weld crack.
  • Welding Electrode Types  -  arc weld electrode, barr electrode, carbon electrode, flux-cored electrode, metal electrode, stranded electrode, and tungsten electrode.
  • Welding Heat Input Required  -  How much heat is required to weld.
  • Welding Machine  -  Equipment used to perform the welding procedure.
  • Welding Operator  -  One who operates a welding machine or automatic welding equipment.
  • Welding Procedure  -  The detailed methods and practices, including all joint welding procedures, involved in making a welded joint.  The parameters of the weld procedure include:
    • Base metal strength
    • Electrode strength and type
    • Heat inlut, current, travel dtime, etc.
    • Weld process
  • Welding Procedure Qualification  -  Demonstration that welds made in a manner described in the Welding Procedure Specification will meet prescribed standards.
  • Welding Procedure Specification  -  The written form of the welding procedure for making a specified kind of a welded joint using specified base and filler metals.
  • Weld Reinforcement  -  Weld material in excess of the specified weld size.
  • Welding Rod  -  A filler metal, in wire or rod form, used in gas welding and brazing procedures and those arc welding processes where the electrode does not furnish the filler metal.
  • Weldment  -  An assembly whose component parts are to be joined by welding.
  • Wetting  -  The condition in which a liquid filler metal of flux forms a zero angle of contact on a solid base metal surface.



  • Yield Point  -  The point where an elastic material is permanent change in length with no extra load force.
  • Yield Strength  -  The minimum stress that leads to permanent deformation of the material.
  • Young's Modulus  -  Measures the stiffness of an elastic material.


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Display #
Arc Strike
Backing Ring
Bar to Plate Welds
Beam to Plate Welds
Elements of a Welding Symbol
Flat Plate Welds
Heat Input
Hot Work Permit
Incomplete Fusion
Incomplete Penetration

Tags: Mechanical Engineering