API 653 API 577 Flashcards
P number
group comparable base metal characteristic such as composition, weldability and mechanical properties (reduce # of procedure qualification)
F numbers
electrodes/welding rods group by usability characteristics
F numbers
electrodes/welding rods group by usability characteristics (reduce number of welding procedure and performance qualifications)
A number
steel and steel alloy filler metals are grouped
A number
based on chemical composition of weld metal (minimize # of welding procedure qualifications)
How to minimize burn through?
first weld pass to equipment or piping less than 1/4” thick should be made with 3/32” or smaller diameter welding electrode
low h2 electrodes are ending
ending 5,6,8
What is a nonconformancs?
defects
What action to be taken for non conformance depends on?
depends on the nature of the nonconformance and its impact on the properties
tasks that a welding inspector should perform?
task prior to welding, during welding and upon completion of welding
VI min lightening?
100 foot candles / 1000 lux
welder who qualify with one filler metal can?
well all filler metal having same F number and MAYBE lower F numbers with backing limitiation
SMAW electrode identification
EXXXX (XX - strength, x position - x coating )
GMAW/GTAW electrode identification
ERXXS (S stand for solid wire), (XX Strength)
(min/max) welding on in-service piping the flow rate should be
min is 1.3 ft/s , max is based on process temperature
SMAW
shielded metal arc welding, creates an arc between a covered consumable electrode and the weld pool. WITH FLUX
GMAW arc ?
Gas metal arc welding, produces an arc between a continuously fed filler metal electrode and weld pool.
GLOBAL Transfer
SMAW is what process
manual with flux
Which has a low tolerance for contaminants for filler/base metals
GTAW
SMAW deposition rates
lower than for other processes such as GMAW
advantages of SMAW (5)
- equipment is relatively simple, not expensive and portable
- used in areas of limited access
- process is less sensitive to wind and draft
- most suitable for commonly used metals and alloys
- level of training and experience is lower than others.
welding consumables becomes slightly damp?
can dry in a separate special oven
calibration for UT with what temp?
with 25F of the part to be examined
What is an autogenous weld?
fusion weld made without filler metal
Define HAZ
portion of base metal whose mechanical properties have been altered by the heat of welding, brazing, soldering, thermal cutting
Definite peening
Mechanical working of metals using impact blows.
Which is most widely use arc?
SMAW
How is shielding obtain in SMAW?
Shielding is provided by the decomposition of the electrode coating,
electrode covering? (5)
- prevent excessive atm condition
- prevent excessive grain growth
- influence operability
- enhance mechanical properties
- increase deposition efficiency
SMAW limitations? (2)
- deposition rates are lower
2. slag must be removed from every deposited weld pass
GTAW
gas tungsten arc welding, arc created between non consumable electrode and weld pool
type of current and polarity used for GTAW?
DCEN
Advantages of GTAW? (5)
- produces high purity welds
- requires little postweld cleaning
- allow for excellent control of root pass
- used with or without filler metals
- produces a relatively defect and contaminant free root passes
Limitations of GTAW (4)
- low deposition rates
- low tolerance for contaminants even than SMAW
- difficulty in shielding the weld zone properly
- greater operator skill
GMAW how is shielding accomplish?
shielding gas
GmAW-S stand for?
short circuiting mode,
GMAW-s high potential of causing?
lack of sidewall fusion
advantages of GMAW
- only consumable electrode process that used most common metal/alloys
- depositing rate high than SMAW and GTAW
- minimal post weld cleaning is required
Limitation of GMAW?
- welding equipment is more complex, costly, and less portable
- welding arc must be protected by air drafts
- GMAW-S is more susceptible lack of fusion
FCAW?
flux contained arc welding, continuously fed tubular electrode
advantages of FCAW (5)
- metallurgical benefits derived from the alloying element in the flux
- slag that supports and shapes the weld bead (allows for a lower cooling rates)
- high deposition that SMAW and GTAW
- shielding produced at the surface of the weld that makes it more tolerant of stronger air currents than GMAW
limitation of FCAW? (5)
- more complex, costly, less portable than SMAW
- self shielding generate large volume of welding fumes
- slag must be removed between weld passes
- backing material is required for root pass welding
- shelf shield is typically not recommend for pressure contain welds
SAW
Submerged arc welding, arc between a flux covered bare metal electrode and weld pool
SAW shielded by
blanket of granular flux covering the arc and molten metal
Advantage of SAW? (2)
- provides high metal deposition rates
2. produce repeatable high quality welds for large weldments
limitation of SAW? (4)
- power supply cable of providing high amp at 100% duty cycle
- weld is not visible during the welding process
- equipment costly, extensive
- process is limited to shop application and flat positions
why should lower h2 electrode be stored away from electrode with higher h2 content?
to prevent absorption of h2 from the high h2 electrodes
If electrodes are wet , what to do?
discard them
why is moisture a concern with low h2 electrodes
- covered electrodes to become unstable
2. moisture can be source of hydrogen
what is susceptible to moisture pickup?
- low h2 electrodes
2. SS electrodes
For welders, a minimum of ______length of the first production weld must be examined for performance
qualification, while a minimum of _____length must be examined for welding operators.
6 in. (150 mm) / 36” (3ft)
What is addressed on the WPQ ( welder performance qualification)
essential variables
GTAW welding process is qualified, any other processed welder is qualified for
NO OTHER just GTAW
who must supervise and control the welding of the WPQ coupon
employer of the welder
WPS/PQR/WPQ format
not fixed provided it addresses (everything)
best results for MT?
when the lines of flux are perpendicular to the discontinuity.
MT overlap requirement?
at least 2”
When to use WFMT
for added sensitivity
ACFM technique?
alternative current field measurement, non contacting technique used for complex geometries.
ACFM(3)
- minimal surface preparation
- elevate temp up to 900F
- less sensitive and more prone to errors than WFMT
ET eddy current?(3)
- subsurface discontinuities
- surface imperfections
- measure thickness of coating / cladding thickness
What exposure technique should be used when possible?
single wall exposure
double wall viewing is limited to what size? (ellipse type) and # of exposure?
<3.5” , min 2 at 90 degree
shear wave in UT is used for ?
detecting discontinuities in welds
how often UT instrument be calibrated?
Prior to use and after used
UT overlap?
previous pass by 10% of the dimension of the transducer
Pressure test should be held for?
30 mins or long enough for a thorough inspection to be completed
why shielding gas is protected by argon / nitrogen?
minimize the formation of oxides that could effect the corrosion resistance of the weld
high electrical conductivity = high thermal conductivity
means more heat input to melt (poor conductor of heat = less heat)
welds are ____dense than wrought steel
less dense
concerns when welding in piping?
burn through / cracking
Ut examine what is temp variable allowed?
25F
welder performance qualification expires?
not used during any 6 month period
welding is most similar to
a casting
what is toughness?
ability of a metal to absorb energy and deform plastically
LP can detect ?
surface imperfections
MT can detect
surface and near subsurface
UT can detect
surface and subsurface
ET
surface and some subsurface
impact test test for?
toughness
why AWS classification are assigned to electrodes ?
means to identify filler metals for welding procedures
Most used NDE for inspection of welds?
VI
how to do MT?
yolk place perpendicular to the weld
grain size can be kept small if (2)
- max rate of cooling
2. slow heat input
foreign weld metals is called
inclusions
if defect found during welding , what to do?
correct before welding further
CUI prevention is best achieved
by coating/insulation barriers
penetrating a thin component with the welding arc while hot tap is called
burn through
crack
fracture type discontinuity characterized by a sharp tip and high ratio of length to width
defect that can caused y residual magnetic field?
arc blow - Deflection of an arc from its normal path due to by magnetic forces.
AWS classification purpose
provide a means to identify filler metals for the welding process
