120102h Flashcards
For each term answer whether it is a dimensional defect, structural discontinuity, or a defective property
A) overlap
B) insufficient Root opening
C) lack of fusion
D) warping
E) Filler metal composition
F) excessive reinforcement
G) incorrect joint preparation
H) incorrect weld size
I) excessive hardness
J) undercut
K) cracking
L) porosity
M) insufficient, tensile strength
N) slag inclusions
I) stray arc strikes
P) poor weld profile
A) overlap- dimensional defect
B) insufficient Root opening - dimensional defect before welding
C) lack of fusion- structural discontinuity
D) warping- dimensional defect
E) Filler metal composition - defective property
F) excessive reinforcement- dimensional defect
G) incorrect joint preparation - dimensional defect
H) incorrect weld size - dimensional defect
I) excessive hardness - defective property
J) undercut - dimensional defect after welding
K) cracking - structural discontinuity
L) porosity - structural discontinuity
M) insufficient, tensile strength - defective property
N) slag inclusions - structural discontinuity
I) stray arc strikes - structural discontinuity
P) poor weld profile - dimensional defect
Which weld fault is considered the most serious explain your answer
Cracking is the most serious because cracks usually continue to spread and lead to complete weld failure
Cutting a notch into both ends of a weld and applying force against one end is known as a
A) stress, flow test
B) weld default test
C) weld press test
D) Nick brake test
D) Nick brake test
Notch affect in a weld has stress flow lines
A) concentrated at one point
B) flowing from left to right
C) flowing smoothly through the welded joint
D) stretched beyond the elastic limit
A) concentrated at one point
A taper transition ratio of 3:1 when joining plates of different thicknesses would
A) waste time and energy
B) decrease notch effect
C) decrease cross-section strength
D) create a point of high stress
B) decrease notch effect
A high concentration of stress in a weld causes
A) stress flow
B) high strength
C) a notch effect
D) a nick break
C) a notch effect
List three weld faults that may be caused by each of the following.
A) inadequate heat input
B) excessive heat input
C) incorrect electrode angle
D) travel speed too slow
E) travel speed too fast
F) contaminated joint area (rust, scale, oil, or paint)
A) any of these: slag inclusions, porosity, lack of fusion, incomplete penetration
B) cracking, undercut, excess penetration
C) undercut, overlap, lack of fusion
D) overlap, excess convexity, excess penetration
E) any of these: cracking, lack of fusion, slag, inclusions, incomplete penetration
F) any of these: porosity, slag, inclusions, lack of fusion, cracking
An insufficient Root opening on a groove weld is likely to cause
A) lack of penetration
B) excessive penetration
C) complete fusion
D) stray ark strike
A) lack of penetration
Which of the following variables would be effective in controlling excessive penetration on a groove weld?
A) reduce the land thickness
B) increase the bevel angle
C) decrease the Root opening
D) preset the plates to widen the groove opening
C) decrease the Root opening
Porosity in a weld can be reduced by
A) cleaning the joint area before welding
B) welding with string beads instead of weave beads
C) maintaining a fast travel speed with the electrode
D) avoiding the use of low hydrogen electrodes
A) cleaning the joint area before welding
Undercut is most commonly caused by
A) current setting to low
B) travel speed too fast
C) using high iron powder electrodes
D) incorrect electrode angle
D) incorrect electrode angle
Distortion can be controlled by
A) making several passes using small electrodes at a low current setting
B) using a long arc length
C) using low hydrogen electrodes
D) maintaining accurate joint fit up
D) maintaining accurate joint fit up
Which of the following can cause quenched and brittle condition in metal
A) a stray arc strike
B) welding current set to low
C) and inadequately filled crater
D) using a damp electrode
A) a stray arc strike
Which situations would most likely produce slag inclusions in multi pass welds
A) Hi current setting with a short arc length
B) hi current setting with a normal arc length
C) low setting with a long arc length
D) removing the slag between passes
C) low setting with a long arc length
Longitudinal cracks in a weld can be caused by
A) excessive travel speed
B) excessive joint restraint
C) arc length too long
D) incorrect electrode inclination
B) excessive joint restraint
Incomplete penetration would likely be caused by
A) travel speed, too slow
B) the Root opening to narrow
C) electrode diameter too small
D) welding with excessively high current settings
B) the Root opening to narrow
Excessive penetration on a Root pass would likely be caused by
A) current settings to low
B) travel speeds too slow
C) Root opening to narrow
D) arc length too short
B) travel speeds too slow
From a welding standpoint, a crater is a term used to describe
A) a person who puts tools in crates
B) a pinhole at the beginning of a weld
C) depression at the end of the weld
D) the cup shaped cavity at the end of used electrode
C) depression at the end of the weld
A weld is said to be concave when the
A) surface of the weld has a slight reinforcement
B) centreline of the weld is below the sides of the weld
C) centreline of the weld is above the sides of the weld
D) centreline of the weld level with the sides of the weld
B) centreline of the weld is below the sides of the weld
____ welds should show a slight reinforcement; ____ welds should be flat to slightly convex across the face.
a) fillet, tee
b) groove, fillet
c) fillet, corner
d) fillet, groove
b) groove, fillet
_____ is a broad term that describes a variety of welding-related issues that may compromise the quality of a weld and its fitness for service.
a) lack of standards
b) code error
c) procedural errors
d) weld fault/defect/discontinuities
d) weld fault/defect/discontinuities
Welding-related codes and standards are useful because they define ______ for welded structures in service.
a) WPS
b) procedural standards
c) acceptance standards
d) weldment procedures
c) acceptance standards
Defects fall into 3 general classifications
a) chemical, dimensional, defective properties
b) chemical , structural, defective procedure
c) dimensional, structural, defective procedure
d) dimensional, structural, defective properties
d)
1. dimensional defects (prior to and after welding),
2. structural discontinuities in the weld or on the surface and
3. defective properties (mechanical or chemical).
Satisfactory welds depend upon maintaining specified dimensions related to:
a) prep, fit up, size & shape of completed welds, finished dimensions of welded assembly
b) prep, size & shape of completed welds,
finished dimensions of welded assembly
c) fit up, size & shape of completed welds,
finished dimensions of welded assembly
d) prep, fit up, size & shape of completed welds,
a) prep, fit up, size & shape of completed welds,
finished dimensions of welded assembly
Departure from specified dimensions in any way is regarded as a _____
a) mechanical or chemical defects
b) defective properties
c) structural discontinuities
d) dimensional defect
d) dimensional defect
List 4 dimensional defects
poor/incorrect material prep
poor/incorrect fit up
incorrect weld size/profile
distortion or warping
_______ in the weld zone are generally caused during the welding operation.
a) mechanical or chemical defects
b) defective properties
c) structural discontinuities
d) dimensional defect
c) structural discontinuities
Weld faults of this nature are often internal,
a) mechanical or chemical defects
b) defective properties
c) structural discontinuities
d) dimensional defect
c) structural discontinuities
To see structural discontinuities you would:
a) visual exam
b) radiographic
c) ultrasonic
d) both b&c
To see structural discontinuities you would: d) use both radiographic and ultrasonic
List the top 2 structural discontinuities
- Porosity
- Lack of fusion
slag inclusions
oxidation
incomplete penetration
cracking
stray arc strikes
True or false
Specific mechanical and chemical properties are often required of the weld metal and base metal of all welds on a given fabrication.
These properties are generally determined with specially prepared test plates, but may be made on sample welds taken from production.
True
Defective Mechanical Properties include which of the following:
tensile strength
yield strength
ductility
hardness
impact strength ( fracture toughness)
incomplete penetration
All except incomplete penetration are defective mechanical properties
tensile strength
yield strength
ductility
hardness
impact strength ( fracture toughness)
A measure of the amount of _____ or pull that a material can withstand. When the _____ is exceeded, the material tears or pulls apart.
a) fracture, fracture toughness
b) yield, yield strength
c) hardness, resistance to indentation
d) tensile, tensile strength
d) tensile, tensile strength
The amount of force required to cause a material to take a permanent upset or deformation.
a) fracture toughness
b) yield strength
c) hardness
d) tensile strength
b) yield strength
The ability of a material to bend or permanently deform without breaking.
a) fracture toughness
b) yield strength
c) ductility
d) tensile strength
c) ductility
A material’s resistance to indentation.
a) fracture toughness
b) yield strength
c) hardness
d) tensile strength
c) hardness
A material’s resistance to extension of a crack.
a) fracture toughness
b) yield strength
c) hardness
d) tensile strength
a) fracture toughness
_______ properties may be deficient in two ways. Incorrect weld metal composition causes too much dilution between the weld metal and base metal, resulting in a loss of corrosion resistance at the weld.
a) physical
b) chemical
c) structural
d) tensile
b) chemical
An incorrect welding procedure can lead to a serious metallurgical condition known as __________
a) convex reinforcement
b) incomplete penetration
c) loss of corrosion resistance
d) intergranular carbide precipitation.
d) intergranular carbide precipitation.
Carbide precipitation leads to a _____ in the area adjacent to the weld.
a) increased surface porosity
b) loss of corrosion resistance
c) increased HAZ
d) incorrect joint prep
b) loss of corrosion resistance
Match the weld faults with the mechanical properties
Fracture toughness, Carbide precipitation, Tensile strength, yield strength, ductility,
1. Dimensional : incorrect joint prep & fit up Structural: surface porosity
2. Dimensional: surface irregularities Structural: badly shaped welds
3. Dimensional: surface discontinuities Structural: excessive spatter
4. Dimensional: surface discontinuities Structural: stray acs
5. Dimensional: incorrect weld profile Structural: lack of fusion, incomplete penetration
Tensile Strength : 1. Dimensional : incorrect joint prep & fit up Structural: surface porosity
Yield Strength : 2. Dimensional: surface irregularities Structural: badly shaped welds
Ductility: 3. Dimensional: surface discontinuities Structural: excessive spatter
Fracture toughness: 4. Dimensional: surface discontinuities Structural: stray acs
Carbide precipitation: 5. Dimensional: incorrect weld profile Structural: lack of fusion, incomplete penetration
True or False
Many discontinuities are caused by the base metal as it does not meet requirements such as:
* chemical composition
* internal conditions (laminations and stringers)
* surface conditions (mill scale, grease, paint or oil)
* mechanical properties and dimensions.
True
______ occurs whenever a notch is placed or formed within the cross-section of a material, creating a point of weakness.
a) changes in cross sections
b) notch effect
c) distortion
d) stress fractures
b) notch effect
Notch effect can happen as a result of:
a) poor joint design
b) poor weld profile
c) structural discontinuities in the weld zone
d) all of the above
d) all of the above
True or false
The term notching effect is derived from the notch break or nick break test
True
When you apply any type of stress to an object, imaginary lines of force known as ______ run through the object.
a) warping stress flow lines
b) stress lines
c) stress flow lines
d) tapered transition lines
c) stress flow lines
True or False
If there is a void in the plate or in a weld within the object, the stress flow lines must go around the fault. They do not go through the fault because the void cannot carry any load.
True
Where ______ are forced to go around a fault, the lines are squeezed together.
This causes a high concentration of stress at this point.
a) warping stress flow lines
b) stress lines
c) stress flow lines
d) tapered transition lines
c) stress flow lines
Where joints are to be made between parts of unequal thickness, failure to taper out rapid changes in the cross-section leads to a severe ______ and possible failure of the weldment.
a) changes in cross sections
b) notching effect
c) distortion
d) stress fractures
b) notch effect
As a general rule, if you use a ______ ratio of 3:1, you will probably have a good welding design that falls within the acceptance criteria of many codes and standards.
a) notched transition
b) flow transition
c) tapered transition
d) lapped transition
c) tapered transition
If you were joining 1” material to 1/2” material. You then multiply 1/2” by 3 which =1.5
You would then taper the thicker material back over a length of
a) 1/2”
b) 1”
c) 1.5”
d) 1.75”
c) 1.5”
What is the ratio used to calculate the amount to taper a thicker material to weld it to a thinner material (tapered transition)
a) 3:1
b) 3:2
c) 4:1
d) 4:2
a) 3:1
If stress flow lines are applied to ________ on lap joints, excess convexity or concavity leads to a _________
a) groove weld, minimal notching effect
b) groove weld, sever notching effect
c) fillet weld, minimal notching effect
d) fillet weld, severe notching effect
d) fillet weld, severe notching effect
True or False
Gussets and corner braces are used on frames and support structures to provide a more gradual change in cross-section
True
With _______ fillet welding, always fill craters and never stop on a corner; instead carry the fillet weld around the corner.
a) continuous
b) intermittent
c) stitch
d) backstep
b) intermittent
________ defects that occur prior to welding are a direct result of poor workmanship.
The 3 general types of weld faults caused by this:
1. incorrect joint preparation and fit-up,
2. irregularities in the surface of the joint preparation and
3. surface discontinuities
a) surface
b) defective properties
c) structural
d) dimensional
d) dimensional
Discontinuities on cut surfaces to be welded may also lead to 3 types of weld faults and defects. List the types of surfaces.
Sheared Surfaces
Flame Cut Surfaces
Gouged Surfaces
True or False
* Sheared discontinuities is caused by poor shear blade condition or the lubricants used
* flame cut discontinuities often occur due to slag adhering to cut surfaces that is not removed prior to welding
* gouging surface discontinuities are caused by improper gouging techniques leaving deposits of carbon, copper or oxidized metal in the joint.
True
What is the code # for surface irregularities - preparation of material
a) 5.3.1
b) 5.3.2
c) 5.3.3
d) 5.3.4
a) 5.3.1
What are the 2 dimensional defects/faults after welding.
distortion/warping
incorrect weld profile
What are the 4 incorrect weld profiles
- convex reinforcement,
- insufficient throat or leg,
- overlap
- undercut.
Weld deficiencies related to weld profiles are based in what CSA Standard
a) A59
b) L59
c) O59
d) W59
d) W59
Label the 4 groove weld profiles in but joints.
Excessive Undercut
Overlap
Excessive convexity
Insufficient Throat
Left: Excessive Convexity
2nd: Insufficient Throat
3rd: Excessive Undercut
4th: Overlap
Excessive convexity tends to produce ________ in multi-pass welds. The term convexity normally refers to a bulging profile of a fillet weld
a) undercut
b) poor weld profile
c) notch effects
d) distortion
c) notch effects
There are several causes of convexity and excessive reinforcement. List the top 3
- travel speed too slow,
- incorrect electrode angle,
- insufficient current.
- incorrect electrode or filler metal size,
- incorrect welding technique and
What are the top 3 effects of convexity
distortion
points of high stress
poor weld profile that causes notch effects
True or False
Insufficient throat or leg (concavity) requires corrective passes
True
Causes of insufficient throat or leg.
a) Excessive heat input causes root to suck back.
b) insufficient # of passes
c) incorrect welding technique
d) all of the above
d) all of the above
Effects of insufficient throat or leg that causes
a) low strength
b) notch effect
c) undercut
d) all of the above
d) all of the above
________ weld deficiencies due to insufficient or excessive size and poor profile may be detected with visual examination or with suitable gauges
a) lap
b) groove
c) fillet
d) corner
c) fillet
_______ is a condition in which an excess of weld metal exists at the toe of a weld beyond the limits of fusion.
a) overlap
b) notch effect
c) cold lap
d) undercut
a) overlap
This condition can produce a notching effect that can result in stress concentrations under load. In the case of a fillet weld, the overlap may actually reduce the weld’s effective size.
a) overlap
b) notch effect
c) cold lap
d) undercut
a) overlap
Overlap is caused by:
a) incorrect welding technique
b) excessive passes
c) incorrect electrode angle & travel speed
d) all of the above
d) all of the above
Results of overlap
a) low strength
b) poor weld metal appearance
c) notch effect
d) all of the above
d) all of the above
also the weld size does not meet specifications
The term _____ describes the melting away of the parent material during the welding process.
a) overlap
b) notch effect
c) cold lap
d) undercut
d) undercut
Can undercut occur at any stage of the welding process?
Yes/No
Yes, undercut can occur at any stage of the welding process
- root bead undercut in single-welded groove welds,
- undercut of the sidewall of a groove at the edge of a layer or bead
- external undercut at the point where the weld metal meets the base metal
Undercut of the _______ of a groove does not affect the completed weld if sufficient care is taken to correct the condition before depositing the next bead.
a) root
b) leg
c) side walls
d) throat
c) side walls
it may be necessary to grind the sidewall undercut to prevent slag inclusion
There are many surface defects. What are the top 3
Surface porosity
excessive spatter
stray arc strike
craters
badly shaped surface ripples on the weld bead
The _______ is usually directly responsible for these defects as a result of improper base metal preparation, incorrect technique or improper current settings.
a) excessive passes
b) base metal composition
c) electrode angle
d) welder
d) welder
_____ irregularities are defects because they constitute an abrupt change of cross-section and may create a notch effect.
a) leg
b) throat
c) toe
d) bead
d) bead
______ is not necessarily a defect in itself, but it indicates improper welding techniques, incorrect current settings or the likelihood of other associated faults.
a) excessive concavity
b) spatter
c) lack of fusion
d) undercut
b) spatter
_______ create a quenched, hard and brittle condition (often called a metallurgical notch) in steels, especially alloys.
a) undercut
b) notch effect
c) cold lap
d) stray arc strikes
d) stray arc strikes
Internal discontinuities fall into what 2 categories
a) spherical
b) columnar
c) helical
d) laminar
Internal discontinuities fall into categories
a) spherical & d) laminar
_______ faults tend to be less serious unless they are present in large quantities or are positioned in line.
a) spherical
b) columnar
c) helical
d) laminar
a) spherical
Spherical discontinuities include
porosity & inclusions
_____faults are found in the form of:
lack of fusion
incomplete penetration
cracking
a) physical
b) discontinuities
c) laminar
d) surface
c) laminar
________ (also called pinholes, gas pockets, wormholes and piping) refers to gaseous voids trapped within the weld metal.
a) cracks
b) undercut
c) porosity
d) over roll
c) porosity
Some porosity may appear on the surface of a weld, so it can be detected visually. However, when the porosity is sub-surface, special testing such as _____________ is necessary to detect it.
a) ultrasonic
b) magnetic
c) radiography
d) bending
c) radiography
Does porosity tend to accumulate as additional passes are added?
Yes and the porosity must be completely removed before additional passes are added
The following items are the cause of what weld failure
* moisture in the electrode or parent metal or both,
* chemistry and structure of the parent material
* surface impurities and contaminants,
* faulty electrodes, fluxes, insufficient gas shielding, trapped slag and
* incorrect welding techniques.
a) cracks
b) under fill
c) porosity
d) under cut
c) porosity
_________ pick-up in flux-coated electrodes or flux-cored wire can cause porosity.
a) contaminant
b) moisture
c) mill scale
d) lamination
b) moisture
The same situation pertains to externally applied flux in welding processes such as submerged arc welding.
In cases such as ________-bearing steels, porosity is commonly encountered.
a) high sulphur
b) high carbon
c) high iron
d) high manganese
a) high sulphur
Other elements, such as zinc found on galvanized steels, may also create excessive porosity in the weld.
Materials with dense oxides, such as aluminum, should be carefully cleaned to avoid_______. Laminations in plate may also be a source of ________ in the welding operation.
a) cracks
b) under fill
c) porosity
d) under cut
c) porosity
This term describes oxides and other non-metallic solids that are sometimes found as elongated or irregular shaped inclusions in welds.
a) slag inclusions
b) in inclusions
c) worm holes
d) pin holes
a) slag inclusions
What is the #1 factor in slag becoming trapped in weld metal?
Current setting to low (amps)
Do slag inclusions cause a notch effect?
Y/N
Yes slag inclusions like porosity can cause a notch effect
The majority of slag inclusions may be prevented by:
a) proper voltage settings
b) proper welding techniques
c) proper welding position
d) proper filler metal
b) proper welding techniques is #1
followed by
Correct current settings
Complete interpass slag removal
Proper joint prep
Correct filler metal selection
Tungsten inclusions are characteristic of :
a) SMAW
b) SAW
c) GTAW
d) GMAW
c) GTAW
If the tungsten ______ contacts the molten weld metal, tungsten particles may separate from the electrode and become trapped in the deposited metal.
electrode
Using excessive heat settings or a contaminated electrode can also cause tungsten ______.
a) worm holes
b) pin holes
c) inclusions
d) slag inclusions
c) inclusions
Due to its _________, the tungsten does not fuse to the deposited weld metal, creating the same problems as porosity or slag inclusions.
a) high melting point
b) low melting point
c) High yield strength
d) low yield strength
a) high melting point
How do you prevent tungsten inclusions list 3:
- Avoid touching the electrode to the molten metal.
- Keep the electrode clean.
- Maintain heat settings within the parameters for the electrode size.
Copper inclusions occurs when a piece of copper; from the coating on a carbon arc-air_____, falls into the groove and is subsequently welded over.
electrode
Copper______ may also occur when magnetic particle testing of welds is done.
a) worm holes
b) pin holes
c) inclusions
d) slag inclusions
c) inclusions
The current for the _______ may be passed through copper conductors (prods). If there is poor contact between the prods and the steel when the current is applied, arcing can occur and copper particles may be melted into the weld.
a) DCEN
b) DCEP
c) magnetic field
d) straight polarity
c) magnetic field
Another cause of copper inclusions is accidental arcing through damaged __________.
a) ground cables
b) welding cables.
c) base metal
d) electrode
b) welding cables.
What is another term for cold lapping
lack of fusion
_______ describes the failure to fuse the weld metal to the base material or adjacent layers of weld metal to each other.
lack of fusion or cold lapping (both mean the same)
_________ is more common with gas shielded welding processes (especially GMAW using short-circuit metal transfer where the puddle can build on itself and not be melted into the parent metal
a) spatter
b) lack of fusion
c) slag inclusions
d) porosity
b) lack of fusion
What are the following causes of_________
- electrode to large for the joint prep
- wrong filler metal
- insufficient current (amps)
- improper manipulation of the electrode
a) spatter
b) lack of fusion
c) slag inclusions
d) porosity
b) lack of fusion
Does lack of fusion cause notch effect?
Yes, and it weakens the weld.
What is the only way lack of fusion is detectable?
a) visual exam
b) ultrasonic testing
c) x-ray texting
d) magnetic testing
b) ultrasonic testing
What are the 3 main ways of preventing lack of fusion.
Prep the joint properly
use the correct current settings
select the correct filler metal
______ describes the failure of the deposited weld metal to fuse fully and completely with the parent material at the root of the weld
a) concave weldment
b) incomplete penetration
c) lack of fusion
d) cold roll
incomplete penetration
(sometimes identified as IP)
________ becomes a weld fault when the amount of weld penetration does not meet the requirements of the applicable codes, specifications or standards.
a) concave weldment
b) incomplete penetration
c) lack of fusion
d) cold roll
b) incomplete penetration
These top 3 causes describe what weld failure?
- poor joint design,
- poor fit-up which causes inadequate gap between the root faces,
- insufficient welding current
a) concave weldment
b) incomplete penetration
c) lack of fusion
d) cold lap
b) incomplete penetration
What weld fault is the most serious
a) cracking
b) incomplete penetration
c) lack of fusion
d) cold lap
a) cracking
* because cracks can be difficult to detect and usually lead to complete joint failure.
* cracks can occur after all welding is complete
What are the 2 types of cracking?
Hydrogen induced cold cracking
Solidification cracking
__________ develops after the weld metal has cooled and can occur in the weld metal or in the heat-affected zone (HAZ).
a) cold cracking
b) incomplete penetration
c) lack of fusion
d) cold lap
a) cold cracking ( hydrogen induced cold cracking
True or False
The 2 conditions that lead to cold cracking are:
* hydrogen from moisture, oils, rust
* low temps
True
______ cracks are usually longitudinal and most often occur at the root or the toes of the weld.
a) short leg
b) root bead
c) HAZ
d) throat
c) HAZ
_____ cracks (across the weld) may also start in the weld metal and may extend through the HAZ and beyond.
a) parallell
b) cross section
c) vertical
d) transverse
d) transverse
_______ may cause fine micro-cracks that are difficult to detect by visual inspection or even non-destructive testing. These cracks may continue to grow until they cause failure much later (sometimes years).
a) cold cracking
b) incomplete penetration
c) lack of fusion
d) cold lap
a) cold cracking
Cold cracking of steel results from the introduction of excess_____ into the weld zone.
a) magnesium
b) oxygen
c) hydrogen
d) argon
hydrogen
________ may come from various sources such as:
* cellulose coated electrodes,
* water on the plate or electrode (for example, unbaked 7018) or external sources on the base material, such as oil or rust.
a) magnesium
b) oxygen
c) hydrogen
d) argon
c) hydrogen
________ is also known as hot cracking, crater cracking, centreline cracking, longitudinal cracking,
a) cold cracking
b) incomplete penetration
c) solidification cracking
d) cold lap
c) solidification cracking
also called hot cracking
With_______ cracking: during the solidification of weld metal, grains begin to grow from the fusion boundary
towards the central region of the weld pool.
a) cold
b) solidification
b) solidification
Sometimes referred to as star cracks, crater cracks are a type of _____ crack which are usually caused by improper termination of the welding arc. Always try to withdraw the electrode slowly from the weld zones that molten metal has time to refill the crater.
a) hot
b) cold
a) hot
Crater cracks occurring during solidification are more likely to form in a ______ crater.
a) short
b) long
c) no predictable length
d) vertical crater across the face of the weldment
b) long
A ____ crater displays crystals radiating from the centre
a) short
b) long
a) short
A mechanical cause of cracks is strain (tension)
What are the top 3 causes?
High restraint on the joint
rapid cooling
poor joint fit up
Some steel alloys that contain significant amounts of alloying elements are more prone to cracking, especially those higher in ______.
a) nickle
b) manganese
c) carbon
d) iron
c) carbon
______ usually require preheating to slow the cooling rate and prevent cold cracking.
a) alloys
b) carbon base metals
c) iron base metals
d) composite base metals
a) alloys
if a _____ tack weld is made on the cold surface of a large mass of metal, the result is a rapid quench effect. If the tack is too _____, a crack may occur because of the rapid cooling and the shrinkage that occurs.
a) small
b) large
c) continuous
d) staggered
a) small
This can also be true of penetration root beads made with small electrodes on thick materials. The rapid quench effect from the surrounding material leaves the _______ and the weld metal brittle and prone to cracking.
a) tack
b) throat
c) root
d) HAZ
d) HAZ
Low hydrogen electrodes (for example, _____, GMAW, GTAW) must be used to prevent cold cracks.
a) 7010
b) 7014
c) 7018
d) 6010
c) 7018
More ______ helps to prevent cold cracks by slowing the cooling rate, but may cause hot cracks to form.
a) surface prep
b) preheat
c) post heat
d) local heat
b) preheat
Large welds which cool more slowly, reduces cold cracking, but may increase hot cracking.
True or False
True
Which of the following parent metal characteristics could cause porosity? (23)
lamination
dense oxides
high sulphur content
all of the above
all of the above
An excessively concave cap on a fillet weld will: (8)
a) reduce the chances of notch effect
b) cause an interruption of stress flow lines
c) reduce the amount of distortion in the weld
d) will increase the load carrying capacity of the structure
b) cause an interruption of stress flow lines
Solidification cracking could also be referred to as: (32)
hot cracking
crater cracking
longitudinal cracking
all of the above
all of the above
Slag inclusions can: (26)
create a notch effect
be caused from low current settings
be reduced with proper welding techniques
all of the above
all of the above
Which weld fault listed presents the most serious notching effect: (30)
internal cracks
internal porosity
bead edge undercut
Incorrect Response
excessive weld overlay
internal cracks
Hydrogen finds its way into welds by: (32)
cellulose electrodes
tungsten electrodes
argon shielding gas
distortion caused by welding
cellulose electrodes
A metallurgical notch is caused by: (21)
a) an excessive cap on a fillet weld
b) too high of a preheat temperature
c) an accidental stray arc on the pipe
d) electrodes that do not have enough moisture in the coating
c) an accidental stray arc on the pipe
Structural discontinuities are generally caused: (3)
before the welding operation (poor fit up)
after the welding operation (distortion)
by incorrect electrode selection
during the weld operation
during the weld operation
Gaseous inclusions such as porosity can be caused by: (23)
a) surface impurities and contaminants
b) using too short of an arc length
c) a very fluid puddle
d) slow travel speeds
a) surface impurities and contaminants
A surface defect may include: (20)
porosity
stray arc
excessive spatter
all of the above
all of the above
Copper inclusions may be caused by: (28)
a faulty amperage setting
incorrect buffing wheels
damaged welding cables
incorrect grinding discs
damaged welding cables
Hydrogen induced cold cracks: (31)
a) occur while the weld is cooling
b) occur before the weld is complete
c) develop after the weld has cooled
d) occur while welding the root bead in piping
c) develop after the weld has cooled
Warpage is classed as a/an: (3)
internal weld fault
external weld fault
dimensional weld fault
structural discontinuity
dimensional weld fault
When referring to the profile of a weld the term excess convexity refers to: (15)
a depression
a flat profile
a bulging profile
an uneven profile
a bulging profile
Lack of fusion or cold lap is most common with: (28)
SAW process
FCAW process
SMAW process
GMAW process
GMAW process
Which of the following is a dimensional weld fault? (3)
warpage
gas pocket
slag inclusion
lack of fusion
warpage
Plates that differ in thickness should be tapered with a ratio of_____ to meet codes and standards. (7)
3:1
4:1
5:1
6:1
3:1
To correct insufficient face reinforcement on a groove weld going into a working environment you could: (16)
a) add corrective passes
b) grind weld deposit down smooth
c) machine weld deposit down smooth
d) all of the above
a) add corrective passes
Excessive weld reinforcement when associated with groove welds can be referred to as: (15)
a) high in stress
b) a notch effect
c) poor weld profile
d) all of the above
d) all of the above
Cold cracking is caused by: (32)
argon
oxygen
nitrogen
hydrogen
hydrogen
Gas voids in weld metal that are free from all solid matter are known as: (22)
craters
dilution
porosity
Impurities
porosity
Porosity could be caused from: (23-25)
a) moisture in the shielding gas
b) slag residue trapped inside welds
c) damp coating on flux coated electrodes
d) all of the above
d) all of the above
Incomplete penetration is classified as a weld fault if: (30)
a) the amount of penetration does not meet the code requirement
b) the root pass does not completely penetrate joint
c) there is excessive reinforcement on root bead
Incorrect Response
d) all of the above
a) the amount of penetration does not meet the code requirement
Incomplete penetration is often caused by: (30)
a) a short arc length
b) welding speed too slow
c) root opening too narrow
d) low hydrogen electrodes
c) root opening too narrow
Another name for lack of fusion could also be referred to as:(28)
cold lap
concavity
convexity
undercutting
cold lap
The cause of excessive convexity or reinforcement could include: (15)
insufficient current
travel speed to slow
incorrect electrode angle
all of the above
all of the above
Which of the following may cause overlap: (18)
excess voltage
excess amperage
incorrect welding technique
all of the above
incorrect welding technique
A loss of corrosion resistance in austenitic stainless steel could be caused by: (4)
a) removing the mill scale
b) a lack of pre-heat prior to welding
c) intergranular carbide precipitation
d) cooling the weld area when welding the joint
c) intergranular carbide precipitation
Lack of fusion is caused by: (29)
a) too large an electrode
b) improper manipulation of the electrode
c) insufficient current
d) all of the above
d) all of the above
Copper inclusions are caused by: (27)
a) oxy-acetylene braze welding
b) carbon arc cutting with air
c) gas tungsten arc welding
d) all of the above
b) carbon arc cutting with air
Incorrect weld profile could include: (14)
overlap
undercut
insufficient throat
all of the above
all of the above
Transverse cracks: (31)
a) form across the weld
b) are not found in the HAZ
c) form along the toe of the cap
d) are parallel with the weld bead
a) form across the weld
Weld faults and defects could be caused by: (11)
a) lubricants from shear blades
b) particles of slag adhering to weld edges
c) carbon or copper deposits on weld preparations
d) all of the above
d) all of the above
Sulphur bearing steels are prone to: (23)
porosity
hot cracking
crater cracks
slag inclusions
porosity
Which one of the following would not be considered a cause of incomplete penetration? (30)
poor fit-up
short arc length
poor joint design
insufficient welding current
short arc length
The three general classes of weld faults are: (3)
a) mechanical, chemical and physical faults
b) dimensional, structural and metallic properties
c) dimensional, structural and defective properties
d) dimensional, structural and mechanical properties
c) dimensional, structural and defective properties
How does notching effect alter stress flow lines in a welded structure? (7)
a) perform a tensile test to identify notch toughness
b) the hardness of the metal could lead to notch effect
c) failure to taper cross sectional changes could lead to a notch
d) stress flow lines are imaginary lines of force and do not affect the weld
c) failure to taper cross sectional changes could lead to a notch
Notching effect in a weldment refers to stress flow lines: (7)
a) flowing from left to right
b) being too short for the plate
c) being concentrated at one point
d) being stretched beyond the elastic limit
c) being concentrated at one point
Which would be classified as an example of a dimensional defect? (3)
distortion
excessive cap
incorrect fit up
all of the above
all of the above
Lack of fusion is detected by: (29)
visual inspection
ultrasonic inspection
radiographic inspection
magnetic particle inspection
ultrasonic inspection
