82 Questions
What is backgouging in welding?
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
What is an arc strike in welding?
A discontinuity resulting from an arc, consisting of any localized remelted metal, heat-affected metal, or change in the surface profile of any metal object
What does insufficient throat refer to in welding?
The distance from the root of the weld to the face of the weld
What is the main cause of undercut in welding?
Excessive heat input during the welding process
What is the purpose of backgouging in welding?
To facilitate complete fusion and complete joint penetration upon subsequent welding from the root side of the joint
What is the main consequence of incomplete fusion in welding?
Reduced joint strength and integrity
What is the maximum stress a material can withstand while being stretched?
Ultimate tensile strength
What is the type of force that tends to pull an object in opposite directions?
Tension
What does weld reinforcement refer to in a groove weld?
Excess weld metal
What is the point where the weld metal intersects the base metal and extends furthest into the weld joint?
Weld root
What is the groove melted into the base metal adjacent to the weld toe or weld root?
Undercut
What do dimensional errors, such as incorrect bevel angles and root openings, indicate in weld discontinuities?
Process-related discontinuities
What is the definition of complete joint penetration (CJP)?
A groove weld condition where weld metal extends through the joint thickness
What is the purpose of a backing in welding?
To support and shield molten weld metal
What is the definition of ductility?
The property of a material to sustain large permanent changes in shape without breaking
What is the definition of hardness?
A measure of how resistant solid matter is to various kinds of shape change when a force is applied
What is the purpose of nondestructive testing (NDT) in welding?
To evaluate components without damaging them
What is the definition of porosity in welding?
Cavity-type discontinuities formed by gas entrapment during solidification
What is the purpose of requesting Mill Certificates for ordered material?
To ensure receipt of the correct type and grade of material
What is the potential consequence of excessive convexity in welds?
Stress risers, slag inclusions, incomplete fusion, and porosity
What does underfill, a groove weld defect, do to the effective load carrying capacity of the joint?
Reduces it
What is the consequence of excessive weld reinforcement?
Stiffens the section, establishes notches, and increases weight
What is overlap in welding and what can it cause?
An excess of weld metal at the toe, causing stress concentration and potential incomplete fusion
What does familiarity with code and procedure requirements allow for?
Informed decisions on cutting and preparation methods
What can insufficient root opening result in?
Inadequate joint penetration, incomplete fusion, and slag entrapment
What may excessive root opening lead to?
Melt-through, porosity, slag entrapment, and additional distortion
What can misalignment of parts cause?
Insufficient effective throat and stress concentration at the weld root
What do codes and specifications provide workmanship tolerances for?
Bevel angle, root face thickness, and root openings
What can surface irregularities such as sheared, flame-cut, plasma-cut, and water jet-cut surfaces lead to?
Various weld discontinuities
What can oxyfuel cutting with oxygen result in?
Notches and irregularities, potentially leading to porosity, incomplete fusion, and slag entrapment
What is the purpose of backgouging in welding?
To facilitate complete fusion and complete joint penetration upon subsequent welding from the root side
What does insufficient throat refer to in welding?
Inadequate depth of the weld within a joint
What is the main consequence of incomplete fusion in welding?
Reduced load carrying capacity
What does weld reinforcement refer to in a groove weld?
The weld metal that extends beyond the surface of the base metal
What is the maximum stress a material can withstand while being stretched or pulled before necking?
Ultimate tensile strength
What is the stress at which a material begins to permanently deform?
Yield strength
What is the type of force that tends to pull an object or a surface of an object in opposite directions?
Tension
What is the internal force induced in a material to counterbalance an externally applied force, represented by the Greek letter sigma, Ơ?
Stress
What is a nonmetallic product resulting from the mutual dissolution of flux and nonmetallic impurities in welding or brazing processes?
Slag
What is the excess weld metal required to fill a groove weld?
Weld reinforcement
What is the detailed methods and practices involved in the production of a weldment?
Welding procedure
What is the misalignment of joint members?
Weld joint mismatch
What is the groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal?
Undercut
What is the points, shown in cross-section, at which the weld metal intersects the base metal and extends furthest into the weld joint?
Weld root
What is the document detailing the requirements and acceptance criteria demanded by a buyer for a product, forming the basis of a contractual agreement?
Specification
What is a document against which a product is judged, summarizing requirements for welding processes, procedures, consumables, materials, inspection, and acceptance criteria?
Standard
What is the distance that a weld fusion extends into the base metal or previous pass from the surface melted during welding?
Depth of fusion
What is the measure of how resistant solid matter is to various kinds of shape change when a force is applied?
Hardness
What is the localized structural damage that occurs when a material is subjected to cyclic loading?
Fatigue
What is the physical property of a material to sustain large permanent changes in shape without breaking?
Ductility
What is a weld of approximately triangular cross-section joining two surfaces approximately at right angles to each other?
Fillet weld
What is the included angle between the groove faces of a groove weld?
Groove angle
What refers to the metal or alloy being welded, brazed, soldered, or cut?
Base metal
What is a material or device placed behind the joint to support and shield molten weld metal?
Backing
What is a discontinuity that renders a part or product unable to meet minimum acceptance standards?
Defect
What is a measure of the how much a material can stretch without breaking?
Elongation
What refers to examination methods where a component or assembly is evaluated without damaging its intended service life?
Nondestructive Testing (NDT)
What is a weld discontinuity in which fusion does not occur between the weld metal and the fusion faces or the adjoining weld beads?
Incomplete fusion (IF)
What is the consequence of excessive convexity in a fillet weld?
Added stress risers at the toes
What is the purpose of grooving the toes in multipass welds?
To correct excessive convexity
What is the main consequence of overlap in welding?
Stress concentration and incomplete fusion
What does excessive weld reinforcement in groove welds lead to?
Stiffening the section and creating notches
What is the purpose of grinding in welding?
To correct overlap and excessive convexity
What is the effect of underfill in a groove weld?
Reduces the effective load carrying capacity of the joint
What is the purpose of requesting mill certificates for ordered material?
To ensure proper type and grade of the material
What is the effect of excessive weld reinforcement in a groove weld?
Stiffens the section and establishes notches
What is the consequence of overlap in a weld?
Stress concentration and masking of incomplete fusion
What is the purpose of grooving the toes in welding?
To correct excessive convexity
What does underfill in a groove weld do to the effective load carrying capacity of the joint?
Reduces the effective load carrying capacity of the joint
What is the main consequence of excessive convexity in a fillet weld?
Added stress risers at the toes
What can result from insufficient root opening in welding?
Inadequate joint penetration and incomplete fusion
What may excessive bevel angle lead to in welding?
Need for a larger joint to be filled with weld metal and excessive distortion
What is the consequence of misalignment of parts in welding?
Insufficient effective throat and stress concentration at the root of the weld
What do flame cut surfaces with notches and irregularities in welding lead to?
Porosity, incomplete fusion, and slag entrapment
What is the effect of plasma and laser cut surfaces in welding high-strength steel?
Dross and oxide film causing porosity and crack formations
What is true about water jet cut surfaces in welding?
Do not require cleaning and can be successfully welded on if uniform
What is the potential consequence of sheared surfaces in welding?
Entrapped foreign materials causing porosity, slag entrapment, and incomplete fusion
What do codes and specifications provide workmanship tolerances for in welding?
Bevel angle, root face thickness, and root openings
What can excessive root opening lead to in welding?
Melt-through, porosity, slag entrapment, and additional distortion
What is true about irregularities in the finished surface to be welded in welding?
Can lead to various weld discontinuities
What is the consequence of excessive bevel angle in welding?
Need for a larger joint to be filled with weld metal and excessive distortion
What is the potential result of irregularities in the finished surface to be welded in welding?
Various weld discontinuities
Study Notes
Weld Discontinuities Due to Joint Preparation and Surface Irregularities
- Insufficient root opening may result in inadequate joint penetration, incomplete fusion, and slag entrapment
- Excessive root opening may lead to melt-through, porosity, slag entrapment, and additional distortion
- Misalignment of parts can cause insufficient effective throat and stress concentration at the weld root
- Codes and specifications provide workmanship tolerances for bevel angle, root face thickness, and root openings
- Table 2 summarizes dimensional errors and resulting weld discontinuities or defects
- Surface irregularities such as sheared, flame-cut, plasma-cut, laser-cut, and water jet-cut surfaces can lead to various weld discontinuities
- Oxygen used in oxyfuel cutting can result in notches and irregularities, potentially leading to porosity, incomplete fusion, and slag entrapment
- Plasma cutting can produce dross and oxide film, leading to porosity if not removed before welding
- Water jet cutting does not alter the material's microstructure and does not require cleaning before welding
- Cutting surfaces using oil as a lubricant, such as milling machines, lathes, and saws, require lubricant removal before welding to avoid porosity
- High-strength quenched and tempered steel cutting may require removal of material to prevent crack formations during welding
- Adherence to codes, standards, and company welding procedures is crucial before any cutting and material preparation begins
Welding Procedure and Inspection Guidelines
- Material should be inspected upon receipt to ensure proper type and grade, and mill certificates should be requested.
- Weld profiles of fillet welds should adhere to required tolerances to avoid deficiencies.
- Overlap is an excess of weld metal at the toe of a weld, causing stress concentration and masking incomplete fusion.
- Causes of overlap include incorrect work angles, electrode size, welding parameters, and surface contaminants.
- Proper welding procedures and techniques should prevent overlap, and if it occurs, grinding is necessary.
- Convexity is the maximum distance from the face of a convex fillet weld, causing added stress risers at the toes.
- Excessive convexity can lead to weld discontinuities and may be caused by poor weld metal fluidity.
- Causes of convexity include operator technique, electrode size, welding parameters, and surface contaminants.
- Grinding may be performed to correct excessive convexity on fillet welds, and grooving the toes is recommended for multipass welds.
- Excessive weld reinforcement stiffens the section, establishes notches, and increases weight, and is associated with groove welds.
- Codes, specifications, and standards limit the amount of reinforcement permitted on groove welds.
- Underfill is when the groove weld size of the joint is insufficient, reducing the effective l.
Weld Discontinuities and Surface Irregularities in Joint Preparation
- Insufficient root opening can lead to inadequate joint penetration, incomplete fusion, and slag entrapment.
- Excessive root opening may cause melt-through, porosity, slag entrapment, and additional distortion.
- Misalignment of parts can result in insufficient effective throat and stress concentration at the root of the weld.
- An excessive bevel angle can lead to the need for a larger joint to be filled with weld metal and excessive distortion.
- Codes and specifications provide workmanship tolerances for bevel angle, root face thickness, and root openings.
- Table 2 summarizes dimensional errors and resulting weld discontinuities or defects.
- Irregularities in the finished surface to be welded can lead to various weld discontinuities.
- Sheared surfaces can lead to entrapped foreign materials causing porosity, slag entrapment, and incomplete fusion.
- Flame cut surfaces with notches and irregularities may lead to porosity, incomplete fusion, and slag entrapment.
- Plasma and laser cut surfaces may lead to dross and oxide film causing porosity and crack formations in high-strength steel.
- Water jet cut surfaces do not require cleaning and can be successfully welded on if uniform.
- Machine cut surfaces require removal of lubricant to avoid weld discontinuities such as porosity.
Test your knowledge of weld discontinuities caused by joint preparation and surface irregularities with this quiz. Explore the effects of insufficient and excessive root opening, misalignment, and various cutting methods on weld quality. Learn about workmanship tolerances, dimensional errors, and the importance of adhering to codes and standards.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
