Welder Handbook (Booklets)

2024

VISUAL INSPECTION HANDBOOK This handbook is NOT intended to serve as a work procedure or to replace any existing procedures. It is solely intended to provide basic information about weld conditions, weld gauges, symbols and weld terms. WELDER’S

SUCCESS THROUGH TRAINING “ I hated every minute of training, but I said, “Don’t Quit. Suffer Now and live the rest of your life as a Champion.” Muhammad Ali

Visual Inspection How to Measure a Fillet Size Weld Defects Cracks Cavities Porosity Wormholes Shrinkage Voids Inclusions Slag Tungsten Oxide Incomplete Fusion Incomplete Penetration Incorrect Shape Undercut Overlap Excess Weld Reinforcement Underfill Concave Root Surface Melt-Through Arc Strikes Splatter Joint Design and Types of Welds Parts of a Weld Types of Welding Welding Positions and Symbols Misc.

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Visual Inspection

Responsibilities & Techniques

Visual Inspection Responsibilities When Where

Final visual inspections must be performed:

The weld inspection zone:

When the weld is complete, and in the final surface and heat treated conditions

All work

Completed weld faces plus ½ inch on both sides of weld shall be visually inspected for the entire length of the weld. Gauge where the weld size visually appears to be the smallest To gauge weld size If the weld length is five feet or less, gauge a minimum of once per weld If the weld length is greater than five feet, gauge a minimum of once every five feet.

Before other NDT (when required) Before being made inaccessible for inspection

Visual Inspection Technique

What

How

In order to perform final visual inspection you need:

Distance and angle:

All work

Adequate lighting (use flashlight as needed) Weld gauges (bridge cam and finger gauges recommended) Prescription glasses (as required)

The inspector’s eyes should be within 24 inches of the surface to be inspected and At an angle of at least 30 degrees to the surface being inspected

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How to Measure a Fillet Weld Size

The leg lengths and throat of the largest triangle that can be drawn within the fillet weld cross section.

Size/ Leg

Leg/ Size

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Weld Defects

Types of Defects

External

Internal

Dimensional

Can be identified by a visual inspection method IE: Dye Penetrant and Magnetic Particle testing.

Require a Non-Destructive testing (NDT) method IE: X- Ray or Ultrasonic testing

Defect Classes

CRACKS

CAVITIES INCLUSIONS

INCOMPLETE FUSION

INCOMPLETE PENETRATION

GEOMETRIC IMPERFECTIONS

MISC.

Main Causes: Welding operators carelessness or lack of skill. Adverse working conditions (Hot - Cold). Poor Design or lack of preparation.

Main Defects: ▲ Undercut. ▲ Slag inclusions. ▲ Porosity. ▲ Overlap or over-roll.

▲ Lack of fusion. ▲ Incomplete penetration. ▲ Weld cracking. ▲ Joint Misalignment.

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Cracks

A tear, fracture or fissure in the weld or base metal appearing as a broken, jagged or straight line. Cracks are the most serious defect and are prohibited by industry standards.

Crack Types

Cracking can develop in the weld, heat- affected zone (HAZ), or base metal when localized stress surpasses the metal's ultimate strength. These cracks are categorized as hot or cold and may be longitudinal or transverse in their orientation. Hot cracks, also known as centerline or solidification cracking occur immediately after welds are completed and sometimes while welds are being made. Cold cracks, also known as delayed cracking or hydrogen cracking occur after the solidification of weld metal. Cracks are classified according to their location in the weld. Crack types in welds are throat cracks, crater cracks, transverse cracks, underbead cracks, lamellar tearing, toe and root cracks, fissures, and liquid metal embrittlement.

CRATER CRACK (HOT CRACK)

TRANSVERSE CRACK

LONGITUDINAL CRACK

UNDERBEAD CRACK (COLD CRACK)

TOE CRACK (COLD CRACK)

ROOT CRACK (HOT CRACK)

Most Common Types of Cracks

Hot Cracks

Crater Cracking:

Hot cracks, also known as centerline or solidification cracking occur immediately after welds are completed and sometimes while welds are being made.

Hot cracking mainly caused by a failure to fill up the crater depression at the end of a weld pass. Shrinkage stresses and inadequate weld metal in the crater causes crater cracking. Cold cracking that is usually in the Heat-affected zone (HAZ) of the parent metal Usually a hot cracking phenomenon. Cracking runs along the length of the weld.

Cold Cracks

Underbead Cracks:

Cold cracks, also known as delayed cracking or hydrogen cracking occur after the solidification of weld metal.

Longitudinal Crack:

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Cracks

Cause

Prevention

Weld Metal

Highly Rigid Joint

Preheat Relieve residual stresses mechanically Minimize shrinkage stresses using back-step or block welding sequence Change welding current and travel speed Weld with covered electrode, DCEN; butter the joint faces prior to welding Change to new electrode; properly store and maintain electrodes

Excessive Dilution

Detective Electrodes

Poor Fit-Up

Reduce root opening; build up edges with weld metal

Small Weld Bead

Increase electrode size; raise welding current; reduce travel speed

High-Sulfur Base Metal

Use low-sulfur filler metal

Angular Distortion

Change to balanced welding on both sides of joint

Crater Cracking

Fill crater before extinguishing the arc; use a welding current decay device when terminating the weld bead

Heat Affected Zone (HAZ)

Hydrogen in welding atmosphere

Use low-hydrogen welding process; preheat and hold for 2 hr after welding or post-heat immediately Use low heat input; deposit thin layers; change base metal

Hot cracking

Low Ductility

Use preheat; anneal base metal

High Residual Stresses

Redesign the weldment; change welding sequence; apply immediate stress-relief heat treatment Preheat; increase heat input; heat treat without cooling to room temperature

High Hardenability

Brittle phases in the microstructure

Solution heat treat prior to welding

Effects

Reduces static, fatigue and impact strengths, corrosion performance and leak resistance; all leading to joint failure.

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Corrective Action

Weld metal cracks are removed by gouging and grinding followed by re-welding with the correct welding procedure. HAZ cracks are more difficult to repair. Extensive gouging and grinding may be required with magnetic particle inspection or dye penetrant inspection to ensure complete removal. Butter layers of weld metal may be required to build up locally to the best weld geometry. A weld procedure specific to the individual joint is advisable. Repair using a qualified low hydrogen weld procedure. May require weld procedure utilizing very low (H5) consumables. May need hydrogen to be removed by heat treatment. Inspection & Standards Surface opening cracks can be detected by magnetic particle inspection or dye penetrant inspection. Sub-surface defects can be found by ultrasonic examination and/or radiography depending on the size and orientation of the defect.

Throat cracks are longitudinal cracks that start in the middle of a weld and extend through the weld as more layers are added. They can appear on the surface after cooling. Throat Cracks

Underbead Cracks Underbead cracks are cracks in the HAZ, under the surface of the metal. They can be longitudinal or transverse. Underbead cracks are small and usually don't go all the way through the metal.

Underbead Cracks

Throat Cracks

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Lamellar Tearing Cracking in the parent metal adjacent to the weld arising from weld stresses in the through thickness direction of the plate. The cracking usually occurs in a stepped configuration, associated with lamellar non- metallic inclusions in the plate, parallel to the working direction. Crater Cracks Crater cracks are hot cracks that develops at the crater on the weld metal by improperly ending the welding arc in the crater of the weld. Crater cracks are clearly visible to the naked eye as star-shaped fissures in the small crater formed at the termination of a weld pass.

Transverse Cracks Cracks in the weld perpendicular to the axis of the weld and sometimes extending beyond the weld into the base metal. Transverse cracks that happen when the metal is not very flexible.

Toe Cracks and Root Cracks Cracking in the parent metal adjacent to the weld arising from weld stresses in the through thickness direction of the plate. The cracking usually occurs in a stepped configuration, associated with lamellar non- metallic inclusions in the plate, parallel to the working direction.

Lamellar Tearing

Underbead Cracks

GROOVE

FILLET

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Cavities

Cavities are weld discontinuities consisting of rounded holes of various types, either within the weld or at the surface of the weld. Porosity and wormholes are cavity types formed by gases. Shrinkage voids are a cavity types formed by contraction of the weld material during solidifcation.

Porosity

Cavities

Porosity occurs when gas bubbles accumulate and get trapped inside the weld, weakening it. During welding, gases like steam, hydrogen, and carbon dioxide are produced and can't escape. Porosity creates small holes, while blowholes are comparatively larger holes or cavities. They can be found on the surface or inside the weld metal and may occur alone or in groups, known as cluster porosity.

Shrinkage Voids

Worm Holes

Shrinkage voids are holes that appear when the metal cools and shrinks, often running parallel to the root of the weld.

Wormholes are elongated or tubular cavities caused by excessive entrapped gas.

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Porosity

Cause

Prevention

Excessive hydrogen, nitrogen, or oxygen in welding atmosphere

Use preheat or increase heat input

High solidification rate

Clean joint faces and adjacent surfaces

Dirty base metal or filler wire

Use specially cleaned and packaged filler wire, and store it in clean area

Improper arc length, welding current, or electrode manipulation

Change welding conditions & techniques

Volatilization of zinc from brass

Use copper-silicon filler metal; reduce heat input Use recommended procedures for baking & storing electrodes; preheat base metal

Excessive moisture in electrode covering or on joint surfaces

High-sulfur base metal

Use electrodes w/ basic slagging reactions

Effects

Porosity causes reduced strength and failures in some cases due to fatigue

Corrective Action

Completely remove porosity from all intermediate weld areas. Grind or carbon arc the affected area until the unacceptable porosity is removed from the weld. Weld repair the affected area, if needed.

Inspection & Standards

Excessive hydrogen, nitrogen, or oxygen in welding atmosphere High solidification rate Dirty base metal or filler wire Improper arc length, welding current, or electrode manipulation

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Inclusions

Inclusions refer to solid materials that become trapped within the weld metal. Tungsten, oxides, slag, and flux are among the typical foreign substances that can become entrapped in the molten weld pool and form inclusions.

Slag

Inclusions

Slag inclusions are nonmetallic materials that get trapped in the weld material. Slag is nonmetallic product resulting from chemical reactions of flux and nonmetallic impurities. Slag inclusions can occur between passes or at the groove face. Slag inclusions often occur during certain welding methods like SMAW, FCAW and SAW. Slag inclusions are lighter than the surrounded metal and usually rise to the surface of molten metal, unless they become entrapped in the weld metal. Multiple-pass welds are more likely to have slag inclusions than single-pass welds because slag from the previous pass if not completely removed will become entrapped in the subsequent pass.

Tungsten

Oxide

When droplets of tungsten get entrapped within the weld metal this is called Tungsten Inclusion.

When surface oxides get entrapped in the weld metal this is called Oxide Inclusion.

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Slag Inclusions

Cause

Prevention

Slag Inclusions

Clean surface and previous weld bead

Entrapment of refractory oxides

Power wire brush the previous weld bead

Tungsten in the weld metal

Avoid contact between the electrode and the work; use larger electrode

Improper joint design

Increase groove angle of joint

Oxide inclusions

Provide proper gas shielding

Slag flooding ahead of the welding arc

Reposition work

Poor Electrode manipulative technique

Change electrode or flux

Entrapped pieces of electrode covering

Use undamaged electrodes

Effects

The presence of slag causes concentrated stress which reduces the durability and productivity of the weld metal.

Corrective Action

Completely remove slag from all intermediate weld areas. Remove all loose slag with a needle gun or chipping hammer? Grind all tightly adhering, unacceptable slag from the surface of the base material or weld.

Inspection & Standards

Radiography Test (RT) Incomplete fusion will be detected as a thin, dark line with sharply defined edges. based on how the defect aligns with the X-ray beam's orientation, the line may tend to be wavy and diffuse

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Incomplete Fusion & Incomplete Penetration

Incomplete fusion (lack of fusion) and incomplete joint penetration (lack of penetration) are similar discontinuities. They result from incomplete melting at the interface between weld passes or in the root of the joint.

Incomplete fusion happens more often in some welding methods than in others. It causes unwanted stresses, and most fabrication standards and codes have strict limits on allowing incomplete fusion. Incomplete Fusion Inclusions

Incomplete penetration in a groove weld happens when the weld metal doesn't go all the way through the joint's thickness. During arc welding, the arc starts between the electrode and the nearest part of the base metal. The rest of the base metal gets heated mostly through conduction. If the part of the base metal closest to the electrode is far from the joint root, the heat might not spread enough to reach the necessary temperature for proper fusion at the root. Incomplete Penetration

INCOMPLETE FUSION)

Single Bevel Groove

INCOMPLETE FUSION)

Incomplete Penetration

INCOMPLETE FUSION)

Double Bevel Groove

INCOMPLETE FUSION)

Incomplete Fusion

Fillet Groove

INCOMPLETE FUSION)

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Incomplete Fusion

Cause

Prevention

Insufficient heat input

Use correct type or size of electrode; proper joint design; and proper gas shielding

Incorrect electrode position

Maintain proper electrode position

Weld metal running ahead of the arc

Reposition work; lower current; increase weld travel speed

Trapped oxides or slag on weld groove or weld face

Clean weld surface prior to welding

Effects

The presence of slag causes concentrated stress which reduces the durability and productivity of the weld metal.

Corrective Action

Place ceramic tape or approved metal backing strap on the bottom side of the hole. Weld repair the first side of the hole from the easiest side to weld Once sufficient weld metal has been deposited on the easiest top side; grind or carbon arc the other side of the hole to sound metal. Weld the other side of the hole to the appropriate size or height

Inspection & Standards

Radiography Test (RT) Incomplete fusion will be detected as a thin, dark line with sharply defined edges.

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Incomplete Penetration

Cause

Prevention

Excessively thick root face or insufficient root opening

Use proper joint geometry

Insufficient heat input

Follow welding procedure

Slag flooding ahead of arc

Adjust electrode or work position

Electrode diameter too large

Use smaller electrode or increase root opening

Misalignment of second side weld

Improve visibility or backgouge weld

Failure to backgouge when specified

Backgouge to sound metal if required in welding procedure specification Use wider root opening or smaller electrode in root pass

Bridging of root opening

Effects

The presence of slag causes concentrated stress which reduces the durability and productivity of the weld metal.

Corrective Action

Inspection & Standards

Radiography Test (RT) Incomplete fusion will be detected as a thin, dark line with sharply defined edges.

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Incorrect Shape A groove at the toe or root of a weld either on the weld face or in previously deposited weld metal. Undercut

Weld metal applied to the surface of a weld producing reinforcement greater than that specified. Also referred to as excess weld metal (butt weld) and excess convexity (fillet weld). Excessive Weld Reinforcement

Excessive amperage Too long an arc length

Causes:

Incorrect welding parameters. Weld energy input too high. Travel speed too low. Size and type of electrode and welding position. Incorrect welder technique.

Excessive weaving of the electrode. -Too fast a rate of travel. - Angle of electrode too inclined to the joint face Result: A stress concentration site and a potential site for fatigue

Result: Increased distortion and reduced fatigue life.

Undercut

An imperfection at the toe or root of a weld caused by metal flowing onto the surface of the parent metal without fusing to it. Overlap

Overlap

Incorrect rate of travel. Incorrect “angle of approach”. Too large an electrode size. Too low an amperage.

Causes:

Overlap

Result: Has a similar effect as undercut and produces a stress concentration site due to the unfused weld metal.

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Incorrect Shape Cont’d.

Underfill

A concave root surface is a depression in the weld extending below the surface of the adjacent base metal caused by an underfill in the root pass of a weld, Concave root surface is detected by RT. If considered a defect, the surface may be suitably prepared or cleaned and additional weld metal added. Concave Root Surface reduces the cross-sectional area of the weld below the amount required in the design. Underfill tends to occur primarily in the flat position in filler welding and in the 5G and 6G pipe groove welding positions. Underfill creates a region susceptible to structural failure from insufficient cross section to support the load. Underfill is detected by VT. A discontinuity in which the weld face or root surface extends below the adjacent surface of the base metal. Underfill

Melt through is also called burn through. It is a discontinuity that occurs in butt welds when the arc melts through the bottom of the weld. Melt-through is different than melt-thru, which is visible root reinforcement produced in a joint that is welded from one side. Melt through is detected by RT as a region of excessive thickness in the region of the weld root. Melt Through

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Miscellaneous A discontinuity consisting of any localized re-melted metal, heat effected metal, or change in surface profile of a finished weld or base mate-rial surface resulting from an electrical arc. Note: Arc strikes may develop stress risers, which could lead to cracking. Arc Strikes Causes: Shrinkage of molten metal at weld root. Incorrect weld preparation or insufficient heat input. Incorrect welding technique.

The metal particles expelled during welding that do not form a part of the weld. Splatter Causes: Excessive amperage Too long an arc length Excessive weaving of the electrode. -Too fast a rate of travel. - Angle of electrode too inclined to the joint face Result: A stress concentration site and a potential site for fatigue

Insufficient arc energy to produce a positive penetration bead. An excessively thick root face. Excessive backing pressure. Slag flooding in MMAW.

Excessive Splatter

Result: Reduces

static

and

fatigue

strengths when excessive.

Arc Strikes

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Joint Design and Types of Welds A weld joint is the term used for the specific location where two or more metal pieces are joined through welding. In ensuring a weld of superior quality and optimizing the cost-effective utilization of filler metal, careful attention to joint design is imperative across all weldment types. A proper joint design is pivotal for attaining the requisite strength and ensuring the weld's utmost quality, all while minimizing costs. The chosen joint design plays a decisive role in determining the type of weld necessary.

Groove & Fillet Welds

Five basic joint designs

Groove welds are created in specifically prepared joints to achieve deeper penetration. Groove welds typically need some level of joint preparation, whereas fillet welds can be made on joints without any preparation. When the edges or surfaces of joint members meet at a right angle, the resulting triangular-shaped weld is called a fillet weld. Weld joints should not be too narrow, so as to restrict access of the gas cup. In some cases, using a narrower gas cup, or a gas lens with the electrode extending up to an inch beyond the gas cup will help.

Butt

Corner

Lap

Edge

Edge Joints

Edge joints

Edge joints are a common choice when the pieces to be welded won't face significant stresses. However, they're not the best option if there's a risk of impact or high stress on either or both of the welded pieces. An edge joint happens when the edges of parallel or nearly parallel members come together and are joined by a weld. You can change the joints by using methods like grinding, cutting, or machining to shape the edges into a groove. The groove can take various forms, such as square, beveled, V, J, or U. The primary aim of the groove is to enable adequate penetration or depth of fusion.

Square Groove

Bevel

U-Groove

V-Groove

J-Groove

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Butt Joints

Butt joints

A butt joint occurs when the surfaces of the pieces to be welded meet in the same plane. When done correctly, butt joints exhibit excellent mechanical strength. Joint preparation requires: material removal, and welding to fill the groove. Distortion and residual stresses can be challenges with butt joints. These joints can be designed with or without a backing bar or strip. The edges can be shaped into grooves like square, beveled, V, J, or U. When pieces to be welded meet at approximately a 90˚ angle, creating an "L" shape, it's termed a corner joint. Welds on the inside of the "L" are fillet welds, while those on the outside are groove welds. Corner joints are straightforward to assemble and often need minimal joint preparation. Corner Joints Corner Joints

Square Groove

Square Groove with Root Opening

V-Groove

Beveled Butt

J-Groove

U-Groove

Lap Joints A lap joint exhibits strong mechanical properties, particularly when welded on both sides. The degree of overlap between the joint members is usually determined by the thickness of the plate.

Lap Joints

Double Bevel Groove

Single or Double Fillet

Single Bevel Groove

A T-joint forms when the surfaces of two members meet at about 90˚, creating a "T" shape. T-joints exhibit strong mechanical strength, especially when welded from both sides. Typically, they need minimal or no joint preparation and are easily welded with the right parameters. If only a fillet weld is needed, the edges of the T-joint can be left square. T-Joints

T Joints

Fillet T-Joint

J-Groove

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Fillet Welds Fillet welds are approximately triangular cross-sectional shape and are applied to members with surfaces or edges at roughly 90˚ angles to each other. These welds can match or surpass the strength of the base metal when they are of the correct size and made using proper welding techniques. When assessing the size of fillet welds, it's essential to establish the weld contour first, which refers to the shape of the weld's face.

V-Groove

Flare-V and Flare-Bevel Flared-groove welds get their name from the shape of the pieces being welded. Either one or both of the pieces have a rounded edge, creating a natural groove for welding. Typically, you don't need to do any special preparation for this type of weld. Groove Weld Size When you're told to make a weld on a joint, the size of the weld matters because it needs to handle the applied load. To get groove weld size right, it's crucial to know some terms related to typical groove designs, like a V-groove joint. You should be familiar with terms like groove angle, bevel angle, root face, and root opening. The bevel-groove weld also needs preparation, but only one of the members needs to be beveled. Whether backing is used on single bevel-grooves depends on the joint's penetration requirements. Bevel-Groove For thicker materials, U- or J-grooves are good for getting deep into the material. With thicker materials, U- and J-grooves can use a smaller groove angle and still get the fusion right. The usual groove angle for both U- and J-grooves is about 20˚ to 25˚, and this applies to double U- and double J-grooves as well. U- and J-Grooves Making V-groove welds requires careful preparation. Well-executed V-groove welds provide excellent quality. For the root pass of a weld without backing, some melt-through usually occurs, ensuring proper penetration and fusion to prevent defects.

Fillet Face contours

Flat

Convex

Concave

The groove name is taken from the profile of the groove. A groove weld is made in square, V, bevel, U, J, flare-V or flare-bevel type grooves between workpieces. Groove Welds You can make a square-groove weld with an open or closed groove. Typically, open- square-groove-welds have groove openings of 5/32" or less. If you're welding from one side, you might use a temporary or permanent backup bar or strip. For crucial welds, a consumable insert can be used to ensure the right joint penetration, avoid excessive melt-through, or provide a flush backing to the weld. Square-Groove

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Parts of a Weld

Fillet Weld Definitions

Reinforcement

Toe

Throat Thickness

Leg Length

Effective Throat Thickness

Toe

Heat Affected Zone (H.A.Z) Root Leg Length

Depth of Penetration

Butt Weld Definitions

Toe

Heat Affected Zone (H.A.Z)

Throat Thickness

Reinforcement

Depth of Penetration

Depth of Root Bead “Penetration”

Effective Throat Thickness

(H.A.Z)

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Types of Welding

Welding Processes

Welding Procedures

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Basic Welding Symbols Welding Positions and Symbols

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How Welding Symbols are Used

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How Welding Symbols are Used Con’t.

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Terms and Definitions

The terms and definitions in this glossary are extracted from the American Welding Society publication AWS A3.0-80 Welding Terms and Definitions. The terms with an asterisk are from a source other than the American Welding Society.

*Abrasives. Materials that are usually sharp and are used to clean or grind a surface. They may be used as a powder such as sand to blast the surface or they may be formed into disks or stones to be used by a grinder.

Arc welding (AW). A group of welding processes producing coalescence of workpieces by melting them with an arc. The processes are used with or without the application of pressure and with or without filler metal. As-welded. Pertaining to the condition of weldments prior to subsequent thermal, mechanical, or chemical treatments. *Automatic welding. Welding with equipment that requires only occasional or no observation of the welding and no manual adjustment of the equipment controls. Variations of this term are automatic brazing, automatic soldering, automatic thermal cutting, and automatic thermal spraying. Axis of a weld. A line through the length of a weld, perpendicular to and at the geometric center of its cross section. B Back weld. A weld deposited at the back of a single groove weld. Back gouging. The removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side. *Backing. A material (base metal, weld metal, carbon, or granular material) placed at the root of a weld joint for the purpose of supporting molten weld metal.

Acceptable criteria. Agreed upon standards that must be satisfactorily met.

Acceptable weld. A weld that meets all the requirements and the acceptance criteria.

Actual throat. See throat of a fillet weld.

*Acetylene. A fuel gas used for welding and cutting. It is produced as a result of the chemical reaction between calcium carbide and water. The chemical formula for acetylene is C2H2. It is colorless, is lighter than air, and has a strong garlic-like smell. Acetylene is unstable above pressures of 15 psig (1.05 kg/cm2 g). When burned in the presence of oxygen, acetylene produces one of the highest flame temperatures available. Air acetylene welding (AAW). An oxyfuel gas welding process that uses an air-acetylene flame. The process is used without the application of pressure. This is an obsolete or seldom used process.

Air carbon arc cutting (CAC-A). A carbon arc cutting process variation removing molten metal with a jet of air.

*allotropic metals. Metals that have specific lattice or crystal structures that form when the metal is cool and that change within the solid metal as it is heated and before it melts.

*Alloy. A metal with one or more elements added to it, resulting in a significant change in the metal’s properties.

Backing strip. Backing in the form of a strip.

Backing weld. Backing in the form of a weld.

*American Welding Society. (AWS). Organization that promotes the art and science of welding and that publishes international codes and standards.

Base material. The material that is welded, brazed, soldered, or cut. See also base metal and substrate.

*Amperage. A measurement of the rate of flow of electrons; amperage controls the size of the arc.

Base metal. The metal or alloy that is welded, brazed, soldered, or cut. See also base material and substrate.

Arc strike. A discontinuity consisting of any localized remelted metal, heat-affected metal, or change in the surface profile of any part of a weld or base metal resulting from an arc.

Bend test. A test in which a specimen is bent to a specified bend radius. See also face-bend test, root-bend test, and side-bend test.

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Carbon arc welding (CAW). An arc welding process that uses an arc between a carbon electrode and the weld pool. The process is used with or without shielding and without the application of pressure. carbon electrode. A nonfiller metal electrode used in arc welding and cutting, consisting of a carbon or graphite rod, which may be coated with copper or other materials. *carbon steel. Steel whose physical properties are primarily the result of the percentage of carbon contained within the alloy. Carbon content ranges from 0.04% to 1.4%, often referred to as plain carbon steel, low carbon steel, or straight carbon steel. carbonizing (carburizing). A reducing oxyfuel gas flame in which there is an excess of fuel gas, resulting in a carbon- rich zone extending around and beyond the cone. *cast. The natural curve in the electrode wire for gas metal arc welding as it is removed from the spool; cast is measured by the diameter of the circle that the wire makes when it is placed on a flat surface without any restraint. *cast iron. A combination of iron and carbon. The carbon may range from 2% to 4%. Approximately 0.8% of the carbon is combined with the iron. The remaining free carbon is found as graphite mixed throughout the metal. Gray cast iron is the most common form of cast iron.

Bevel. An angular type of edge preparation.

Bevel angle. The angle formed between the prepared edge of a member and a plane perpendicular to the surface of the member. Refer to drawings for bevel. Braze. A bond produced as a result of heating an assembly to the brazing temperature, 840°F (450°C), using a brazing filler metal distributed and retained between the closely fitted faying surfaces of the joint by capillary action. Braze welding. A welding process variation that uses a filler metal with a liquidus above 840°F (450°C) and below the solidus of the base metal. Unlike brazing, in braze welding the filler metal is not distributed in the joint by capillary action. Brazing (B). A group of welding processes that produces coalescence of materials by heating them to the brazing temperature in the presence of a filler metal with a liquidus above 840°F (450°C) and below the solidus of the base metal. The filler metal is distributed between the closely fitted faying surfaces of the joint by capillary action. Buildup. The material deposited by the welding filler metal to a weld. Also, surfacing variation in which surfacing material is deposited to achieve the required dimensions. See also buttering, cladding, and hardfacing. Burnthrough. A hole or depression in the root bead of a single-groove weld due to excessive penetration. A nonstandard term when used for melt-through.

cathode. A natural curve material with an excess of electrons, thus having a negative charge.

*cell. A manufacturing unit consisting of two or more workstations and the material transport mechanisms and storage buffers that interconnect them. cellulose-based electrode fluxes. Fluxes that use an organicbased cellulose (C6H10O5) (a material commonly used to make paper) held together with a lime binder. When this flux is exposed to the heat of the arc, it burns and forms a rapidly expanding gaseous cloud of CO2 that protects the molten weld pool from oxidation. Most of the fluxing material is burned, and little slag is deposited on the weld. E6010 is an example of an electrode that uses this type of flux.

Butt joint. A joint between two members aligned approximately in the same plane.

Buttering. A surfacing variation depositing surfacing metal on one or more surfaces to provide metallurgically compatible weld metal for the subsequent completion of the weld. C Capillary action. The force by which liquid, in contact with a solid, is distributed between closely fitted faying surfaces of the joint to be brazed or soldered. *Carbon. A nonmetallic element that can be found in all organic and many inorganic compounds, the most common allowing element used in iron to change its mechanical properties.

*cementite. A crystalline form of iron and carbon that is hard and brittle.

*center. A manufacturing unit consisting of two or more cells and the materials transport and storage buffers that interconnect them. *centerline. Lines on a drawing that show the center point of circles and arcs and round or symmetrical objects. They also locate the center point for holes, irregular curves, and bolts.

Carbon arc cutting (CAC). An arc cutting process that uses a carbon electrode. See also air carbon arc cutting.

Carbon arc gouging (CAG). A thermal gouging process using heat from a carbon arc and the force of compressed air or other nonflammable gas.

*certification. See certified welders.

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Welder’s Handbook

certified welders. Individuals who have demonstrated their welding skills for a process by passing a specific welding test. chain intermittent welds. An intermittent weld on both sides of a joint in which the weld segments on one side are approximately opposite those on the other side.

concave fillet weld. A fillet weld with a concave face.

concave root surface. A root surface that is concave.

concavity. The maximum distance from the face of a concave fillet weld perpendicular to a line joining the toes.

conduit liner. A flexible steel tube that guides the welding wire from the feed rollers through the welding lead to the gun used for GMAW and FCAW welding. The steel conduit liner may have a nylon or Teflon inner surface for use with soft metals such as aluminum.

*chill plate. A large piece of metal used in welding to correct overheating.

cladding. A relatively thick layer greater than 1 mm (0.04 in.) of material applied by surfacing for the purpose of improved corrosion resistance or other properties. See also coating, surfacing, and hardfacing.

cone. The conical part of an oxyfuel gas flame adjacent to the orifice of the tip.

coalescence. The growing together or growth into one body of the materials being welded.

constricted arc. A plasma arc column shaped by the constricting orifice in the nozzle of the plasma arc torch or plasma spraying gun. constricting nozzle. A device at the exit end of a plasma arc torch or plasma spraying gun containing the constricting orifice. constricting orifice. The hole in the constricting nozzle of the plasma arc torch or plasma spraying gun through which the arc plasma passes.

coating. A relatively thin layer 1 mm (0.04 in.) of material applied by surfacing for the purpose of corrosion prevention, resistance to high-temperature scaling, wear resistance, lubrication, or other purposes. See also cladding, surfacing, and hardfacing. cold crack. A crack occuring in a metal at or near ambient temperatures. Cold cracks can occur in base metal, heat-affected zones, and weld metal zones. cold soldered joint. A joint with incomplete coalescence caused by insufficient application of heat to the base metal during soldering.

consumable electrode. An electrode that provides filler metal.

consumable insert. Filler metal placed at the joint root before welding and intended to be completely fused into the root of the joint and become part of the weld.

*combustion. A rapid chemical reaction between oxygen and another substance that gives off heat and light.

contact tube. A device that transfers current to a continuous electrode.

*combustion rate. Also known as rate of propagation of a flame, this is the speed at which the fuel gas burns, in ft/sec (m/sec). The ratio of fuel gas to oxygen affects the rate of burning: a higher percentage of oxygen increases the burn rate.

*contamination. Any undesirable material that might enter the molten weld metal.

continuous weld. A weld that extends continuously from one end of a joint to the other. Where the joint is essentially circular, it extends completely around the joint.

complete fusion. Fusion over the entire fusion faces and between all adjoining weld beads.

composite electrode. A generic term for multicomponent filler metal electrodes in various physical forms, such as stranded wires, tubes, and covered wire. See also covered electrode, flux cored electrode, and stranded electrode. *computer-aided design (CAD). Computer software programs that typically use vector lines to produce a mechanical type drawing. *computer-aided manufacturing (CAM). Computer software programs used to aid in the automated manufacturing of parts.

convex fillet weld. A fillet weld with a convex face.

convexity. The maximum distance from the face of a convex fillet weld perpendicular to a line joining the toes.

convex root surface. A root surface that is convex.

copper. A pinkish or peach colored highly thermally and electrically conductive soft metal that resists corrosion.

copper alloys. An alloy primarily containing copper. The two most common copper alloys are brass, a copper tin alloy; and bronze, a copper zinc alloy.

computer control. Control involving one or more electronic digital computers.

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Welder’s Handbook

corner joint. A joint type in which butting or nonbutting ends of one or more workpieces converge approximately perpendicular to one another. *corrosion resistance. The ability of the joint to withstand chemical attack; determined by the compatibility of the base materials to the filler metal. corrosive flux. A flux with a residue that chemically attacks the base metal. It may be composed of inorganic salts and acids, organic salts and acids, or activated rosins or resins.

cross-sectional sequence. The order in which the weld passes of a multiple pass weld are made with respect to the cross section of the weld. See also block sequence. crucible. A high-temperature container that holds the thermite welding mixture as it begins its thermal reaction before the molten metal is released into the mold. *crystalline structures. Orderly arrangements of atoms in a solid in a specific geometric pattern; sometimes called lattices.

cutting attachment. A device for converting an oxyfuel gas welding torch into an oxygen cutting torch.

cosmetic pass. A weld pass made primarily to enhance appearance.

*cutting gas assist. A nonreactive or exothermic gas jet directed on the metal to aid in laser cutting.

*coupling distance. The distance to be maintained between the inner cones of the cutting flame and the surface of the metal being cut, in the range of 1/8 in. (3 mm) to 3/8 in. (10 mm).

cutting head. The part of a cutting machine in which a cutting torch or tip is incorporated.

cover lens. A round cover plate.

*cutting plane line. Lines on a drawing that represent an imaginary cut through the object. They are used to expose the details of internal parts that would not be shown clearly with hidden lines.

*cover pass. The last layer of weld beads on a multipass weld. The final bead should be uniform in width and reinforcement, not excessively wide, and free of any visual defects. cover plate. A removable pane of colorless glass, plastic- coated glass, or plastic that covers the filter plate and protects it from weld spatter, pitting, and scratching. covered electrode. A composite filler metal electrode consisting of a bare or metal cored electrode with a flux covering to provide a slag layer and/or alloying elements. The covering may contain materials providing such functions as shielding from the atmosphere, deoxidation, and arc stabilization and can serve as a source of metallic additions to the weld. crack. A fracture-type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement.

cutting tip. The part of an oxygen cutting torch from which the gases issue.

cutting tip, high speed. Designed to provide higher oxygen pressure, thus allowing the torch to travel faster.

cutting torch. A device used for plasma arc cutting to control the position of the electrode, to transfer current to the arc, and to direct the flow of plasma and shielding gas. *cycle time. The period of time from starting one machine operation to starting another (in a pattern of continuous repetition).

cylinder. A portable container used for transportation and storage of a compressed gas.

cylinder manifold. A multiple header for interconnection of gas sources with distribution points.

crater. A depression in the weld face at the termination of a weld bead.

*cylinder pressure. The pressure at which a gas is stored in approximately 2200 lb per square inch (psi), and acetylene is stored at approximately 225 psi. D DCEN – The arrangement of direct current arc welding leads in which the electrode is the negative pole and workpiece is the positive pole of the welding arc. DCEP – The arrangement of direct current arc welding leads in which the electrode is the positive pole and the workpiece is the negative pole of the welding arc.

crater crack. A crack initiated and localized within a crater.

*creep. A property of metal that allows it to be deformed under a load that is below the metal’s yield point.

crevice corrosion. Oxidation that occurs in the small space (crevice) between two pieces of metal as the result of moisture being trapped in the small space. critical weld. A weld so important to the soundness of the weldment that its failure could result in the loss or destruction of the weldment and injury or death.

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Welder’s Handbook

Defect – A discontinuity or discontinuities that by nature or accumulated effected (for example total crack length) render a part or product unable to meet minimum applicable acceptance standards or specifications. The term designates rejectability. Deoxidizers – Elements, such as manganese, silicon, aluminium, titanium, and zirconium, used in welding electrodes and wires to prevent oxygen from forming harmful oxides and porosity in weld metal.

Divergency – The tapered part of the oxygen bore directly behind the throat in high pressure (high speed) nozzle designs. The divergency allows the high pressure to become close to atmospheric before it leaves the nozzle. This increases stream velocity and improves cut quality by keeping stream uniform. The increased velocity produces 10–15% higher cutting speeds. Double Arcing – A condition in which the welding or cutting arc of a plasma arc torch does not pass through the constricting orifice but transfers to the inside surface of the nozzle. A secondary arc is simultaneously established between the outside surface of the nozzle and the workpiece. Downhill – Welding with a downward progression. Drag – The offset distance between the entrance and exit points of the gas stream on the plate being cut, measured on the cut edge. Drag will increase and decrease with varying conditions such as speed, oxygen pressure, plate thickness, oxygen purity, etc.

Deposited Metal – Filler metal that has been added during welding, brazing or soldering.

Deposition Efficiency – The relationship of the electrode used to the amount of the weld metal deposited, expressed in percent, i.e.; DE = Weight of Weld Metal ÷ Weight of Electrode Used Deposition Rate – The weight of weld metal deposited compared to the time of welding. It is usually expressed in pounds per hour. Depth of Bevel – The perpendicular distance from the base metal surface to the root edge or the beginning of the root face. Depth of Fusion – The distance that fusion extends into the base metal or previous bead from the surface melted during welding. Digging – Refers to the arc characteristics that you normally see with a 6010 electrode. A “digging” arc is one in which you can see parent metal being penetrated at the arc. Dilution – The change in chemical composition of a welding filler metal caused by the admixture of the base metal or previous weld metal in the weld bead. It is measured by the percentage of base metal or previous weld metal in the weld bead. Direct Current – An electrical current which flows in only one direction in a conductor. Direction of current is dependent upon the electrical connections to the battery or other DC power source. Terminals on all DC devices are usually marked (+) or (-). Reversing the leads will reverse the direction of current flow. Discontinuity – An interruption of the typical structure of a material, such as a lack of homogeneity in its mechanical, metallurgical, or physical characteristics. A discontinuity is not necessarily a defect. Distortion – All fusion welding methods produce the weld by moving a molten pool along the weld joint. When the heated metal cools the shrinkage introduces distortion in (or a change in the shape of) the welded structure.

Drag Angle – The angle between the impinging jet stream centerline and a direction perpendicular to the plate surface.

Dross – Re-solidified molten metal and oxides adhering to the top or bottom edge during thermal cutting.

Ductility – The ability of a material to become permanently deformed without failure.

Duty Cycle – A power source specification describing the percentage of time a system can be operated at a given current level. Based on a ten-minute cycle. E Edge Preparation – The preparation of the edges of the joint members, by cutting, cleaning, plating or other means. Effective Throat – The minimum distance minus any convexity between the weld root and the face of a fillet weld. Elastic Limit – The maximum stress to which a material can be subjected without permanent deformation or failure by breaking. Elasticity – The ability of a material to return to original shape and dimensions after a deforming load has been removed. Electrical Stick-Out – In any welding process using a solid or flux cored wire, the electrical stick-out is the distance from the contact tip to the un-melted electrode end. Sometimes called the “amount of wire in resistance”. This distance influences melt-off rate, penetration, and weld bead shape.

Electrode – The plasma arc torch part from which arc current is emitted.

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