B31.3 Flashcards
What does casting quality factors Ec defined?
Ec is used for cast components not have pressure-temperature ratings
What does factors Ej defined?
weld joint quality factor /
are basic factors for straight or spiral (helical seam) welded joints for pressure containing components
How can you increase quality factors?
if additional examination is performed (NDE)
Ec=.8 (2)
- for most other metals, static castings that conform to the material specification and have been visually examined as required by MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges and Fittings and Other Piping Components
- Centrifugal castings that meet specification
requirements only for chemical analysis, tensile,
hydrostatic, and flattening tests, and visual examination
max quality factor
1
For furnace but weld Ej is ? / Any additional QF allowed with NDE?
.6 / No
For ERW Ej is ? / Any additional QF allowed with NDE
.85 / No
seamless pipe Ej?
1.0
Category D Fluid Service: (4) - pressure (max) / temp limits (min/max)
1) the fluid handled is nonflammable, nontoxic, and not damaging to human tissues as defined in para. 300.2
(2) the design gage pressure does not exceed 1 035 kPa (150 psi)
(3) the design temperature is not greater than 186°C 366°F)
(4) the fluid temperature caused by anything other than atmospheric conditions is not less than −29°C
(−20°F)
Category MFluid Service:
the fluid is so highly toxic that a single exposure to a very small quantity of the fluid, caused by leakage, can produce serious irreversible harm to persons on breathing or bodily contact,
stress-relief:
uniform heating of a structure or portion thereof to a sufficient temperature below the transformation temperature range to relieve the major portion of the residual stresses, followed by uniform
cooling slowly enough to minimize development of
new residual stresses
tempering:
reheating a hardened metal to a temperature below the transformation range to improve toughness
difference between normalizing an annealing:
annealing is done in a control environment, normalizing is in ambient temp
seal weld:
a weld intended primarily to provide joint
tightness against leakage in metallic piping
theoretical throat is based on___x the leg length?
.707
spot radiograph for circumferential butt welds?
not less than one shot on one in each 20 welds for each welder or welding operator
spot radiograph for longitudinal butt welds with Ej=0.9
1 feet in each 100 feet
A slip-on flange shall be double-welded when (4) subject to (3) temp
(1) subject to severe erosion, crevice corrosion, or
cyclic loading
(2) flammable, toxic, or damaging to human tissue
(3) under severe cyclic conditions
(4) at temperatures below −101°C (−150°F)
The use of slip-on flanges should be avoided where
many large temperature cycles are expected, particularly if the flanges are not insulated.
a flange to be used under severe cyclic conditions shall be
welding neck
Bolting having not more than 207 MPa (30 ksi) specified minimum yield strength shall not be used for flanged joints (2) (class / material gaskets)
- ASME B16.5 Class 400 and higher,
2. flanged joints using metallic gaskets,
carbon steel bolting may be used with what type of class flanges and temp?
nonmetallic gaskets in flanged joints rated ASME B16.5 Class 300 and lower for bolt metal temperatures
at −29°C to 204°C (−20°F to 400°F), inclusive.
Low yield strength bolting shall not be
used for
flanged joints under severe cyclic conditions.
Tapped holes for pressure-retaining bolting in metallic piping components shall be of sufficient depth that the thread engagement
will be at least seven-eighths times the nominal thread diameter.
when can Fillet welds may be used as primary welds (2)
- to attach socket welding components and slip-on flanges.
- Fillet welds use to attached reinforcement and structural attachments, to supplement the strength or reduce stress concentration of primary
welds, and to prevent disassembly of joints.
Seal welds may be used
only to prevent leakage of threaded joints and shall
not be considered as contributing any strength to the
joints.
what should be done If a backing ring is used where the resulting crevice is detrimental (e.g., subject to corrosion, vibration, or
severe cyclic conditions)
it should be removed and the internal joint face ground smooth.
When it is impractical to remove the backing ring in such a case, consideration shall
be given to welding without backing rings or to the use of consumable inserts or removable nonmetallic backing rings.
Split backing rings shall not be used
under severe cyclic conditions.
Socket welded joints should be avoided in any service
where crevice corrosion or severe erosion may occur.
Socket welds larger than ________ shall not be
used under severe cyclic conditions.
DN 50 (NPS 2)
Where a metallic flange is bolted to a nonmetallic flange both should be
flat-faced. A full-faced gasket is preferred.
Cold spring purposes, and when is it recommend?
serves to balance the magnitude of the reaction under initial and extreme displacement conditions.
piping material of limited ductility
min gap with socket weld joint on the weld?
1/16”
A weld defect to be repaired shall be removed to
sound metal.
Alternative Heat Treatment.
Normalizing, or normalizing and tempering, or annealing may be applied in lieu of the required heat treatment after welding, bending, or forming,
what code provide guidance to PRD design and fabrication?
ASME Section VIII
Examination for Leaks. The leak test pressure shall be maintained for
at least 10 min and then all joints and connections shall be examined for leaks.
For P-Nos. 3, 4, 5A, 5B, 5C, and 15E materials, examinations shall be performed after completion of
heat treatment. However, examinations need not be repeated on welds or portions of welds that are subjected to additional heat treatments and have not been repaired by welding.
Piping in Normal Fluid Service shall be examined with what NDE and requirements?
a) Visual Examination.
1.at least 5% of fabrication
2. 100% of all completed welds,
3.100% of all completed welds, Ej, of 0.90.
4. random examination of the assembly of threaded, bolted, and other joints to satisfy the examiner, When pneumatic testing is to be performed,
all threaded, bolted, and other mechanical joints shall
be examined
b. Not less than 5% of circumferential butt and
miter groove welds shall be examined fully by random
radiography
undercut
a groove melted into the base material adjacent
to the toe or root of a weld and left unfilled by weld
material.
Examination — Elevated Temperature Fluid Service.
(a) Visual Examination.
(1) All fabrication shall be examined.
(2) All threaded, bolted, and other joints shall be examined.
(3) All piping erection shall be examined to verify dimensions and alignment.
(b) Additional Examination. The examination requirements
:
(1) Fabrication for longitudinal and spiral (helical
seam) welds in P-No. 4 and P-No. 5 materials, except
those in components made in accordance with a listed
specification, shall be examined by 100% radiographn accordance with para. 344.5, or by 100% ultrasonic
examination in accordance with para. 344.6.
(2) Socket welds and branch connection welds in PNo.
4 and P-No. 5 materials that are not radiographed or
ultrasonically examined shall be examined by magnetic particle or liquid penetrant methods in accordance
Extent of Radiography for 100%/ random and spot
a) 100% Radiography. This applies only to girth and miter groove welds and to fabricated branch connection welds
(b) Random Radiography. This applies only to girth and miter groove welds.
(c) Spot Radiography. This requires a single exposure radiograph in accordance with para. 344.5.1 at a point within a specified extent of welding. For girth, miter, and branch groove welds, the minimum requirement is
(1) for sizes ≤DN 65 (NPS 21 ∕2), a single elliptical exposure encompassing the entire weld circumference
(2) for sizes >DN 65, the lesser of 25% of the inside circumference or 152 mm (6 in.)
For longitudinal welds, the minimum requirement is 152 mm (6 in.) of weld length.
In-Process Examination type of NDE
VT
Expanded joints shall not be used
under severe
cyclic conditions.
Threaded joints should be avoided
avoided in any service where crevice corrosion, severe erosion, or cyclic loading
may occur
when to used expanded joints?
subjected to vibration, differential expansion or contraction due to temperature cycling, or external mechanical loads.
When threaded joints are intended to be seal welded, thread sealing compound
shall not be used.
pneumatic test requirement? (3)
- PRD not higher than 50 psi or 10% of test pressure
- not less than 1.1 x DP
- cannot exceed (lessor) 1.33x DP or exceed 90 % of YS
Flattening of a bend, the difference between maximum and minimum diameters at any cross section, shall not
exceed 8% of nominal outside diameter for internal pressure and 3% for external pressure. Removal of metal shall not be used to achieve
these requirements.
When welding two different P-No. materials, the preheat temperature shall be
the higher temperature for the material being welded
Pneumatic Test pressure
The test pressure shall be not
less than 1.1 times the design pressure and shall not exceed the lesser of
(a) 1.33 times the design pressure
(b) the pressure that would exceed 90% of the pressure
Pressure Relief Device. A pressure relief
device shall be provided, having a set pressure not
higher than the test pressure plus the lesser of 345 kPa (50 psi) or 10% of the test pressure.
Hydro test presssure
atleast 1.5x design pressure
The preheat zone shall be at or above the specified minimum temperature in all directions from the point of welding for a distance of the
larger of 75 mm (3 in.) or 1.5 times the greater
nominal thickness.
limitation on pressure test (3)
- reduce test pressure - if test pressure exceeds YS
- test fluid expansion - precaution taken for thermal expansion
- preliminary pneumatic test - preliminary leak test using air at no more than 25 PSI to locate major leaks first
examination for leaks should be held for atleast
10 min
when should leak test be conducted
after heat treatment
hydro leak test requirements (2)
- atleast 1.5 x DP
2. when test temp > DT use formula
pneumatic test requirement? (3)
- PRD not higher than 50 psi or 10% of test pressure
- not less than 1.1 x DP
- cannot exceed (lessor) 1.33x DP or exceed 90 % of YS
when is impact test exempt?
the design minimum temperature is warmer than or equal to the temperature listed in the Min. Temp. column of Table A1
impact test requirements (1) what size
All impact tests shall be made using standard 10 mm (0.394 in.) square cross section Charpy V-notch specimen bars, except where shape/thickness does not permit
Impact test for Materials of Thickness Equal to or Greater Than 10 mm
and less than 10MM
(2)
- specimen has a width along the notch of at least 8 mm (0.315 in.), the Charpy test using such a specimen shall be conducted at a temperature NOT higher than the design minimum temperature.
- specimen has a width along the notch LESS than 8 mm, the test shall be conducted at a temperature lower than the design minimum temperature by the amount shown in Table 323.3.4
Impact test For Materials With Thickness Less Than 10 mm
- specimen has a width along the notch of at least
80% of the material thickness, the Charpy test of such
a specimen shall be conducted at a temperature not
higher than the design minimum temperature - specimen has a width along the notch of less than 80% of the material thickness,
the test shall be conducted at a temperature lower
than the design minimum temperature by an amount
equal to the difference
Where two base metals having different required impact test acceptance criteria are joined by welding, the impact test acceptance
criteria shall conform
to the requirements of the base material having a specified minimum tensile strength most closely matching the specified minimum tensile
strength of the weld metal.
impact test Absorbed Energy Criteria?
When the average value of the three specimens equals or exceeds the minimum value permitted for a single specimen AND
the value for more than one specimen is below the
required average value, or when the value for one
specimen is below the minimum value permitted for a single specimen, a retest of three additional specimens shall be made.
impact test Lateral Expansion Criterion?
value of lateral expansion for one specimen in a group of three is below 0.38 mm (0.015 in.) but not below 0.25 mm (0.01 in.), AND
if the average value for three specimens equals or exceeds 0.38 mm (0.015 in.),
a retest of three additional specimens may be made, which must equal or exceed the specified minimum
value of 0.38 mm (0.015 in.)
how to perform Preheat Temperature Verification (2)
- reheat temperature shall be checked by use oftemperature indicating crayons, thermocouple pyrometers, or other suitable means to ensure that the temperature specified in the WPS is obtained prior to and maintained during welding.
- Thermocouples may be temporarily attached directly to pressure-containing parts using the low energy capacitor discharge method of welding
Preheat Zone and for tack welds min temperature distance requirements
- at or above the specified minimum temperature in all directions from the point of welding for a distance of the LARGER of 75 mm (3 in.) or 1.5 times the greater
nominal thickness. - tack welds shall be at or above the specified minimum temperature for a distance not less than 25 mm (1 in.) in all directions
The preheat requirements applies to what types types of welding,
including tack welds, repair welds, and seal welds
on threaded joints.
preheating requirement on 2 diff p material?
the preheat temperature shall be the higher temperature for the material being welded
procedure of a pneumatic test? how to gradually increase requirements?
gradually increased until a gage pressure that is the lesser of one-half the test pressure or 170 kPa (25 psi) is attained, at which time a preliminary check shall be made
impact testing is not required if the design min temperature is below ____F_ but at or above _____ F and the stress ratio doe snot exceed ____.
-20 / -155 and 0.3 and less
what should not be used in closing a gap when performing a cold spring
heat
forging E?
1
Definition of E?
safety factors to reduce the allow stress
required thickness includes CA?
NO, only min required thickness adds C/A
definition of auxillary?
can be isolated from the primary piping
valves are subjected to closing stress and stress concentration b/c of their shape thus the thickness require for flanged fitting and valve is _____
1.35 - 1.5 x thicker than a simple cylinder
purpose of a leak test (3)
- to ensure tightness / NOT a strength test
- minimize risk of brittle fracture
- subject piping system to a higher stress than during design conditions
all piping are required to test a leak test (2)
- category D
2. line pen to atmosphere
leak test duration
10 minutes
pressure leak test shall be accordance to? for both in-service/new
B31.3
socket welded gap?
min 1/16”
is a pressure test required after alteration/
normally and if use NDE then need inspector AND Engineer
can welds be covered by insulation during a leak test
as long as they have been previously tested
how long does the hydrostatic test record need to be maintained?
as long as the report is complete
primary inspection and testing method used during original construction?
visual and pressure test
pneumatic test pressure cannot exceed (2)
- 1.33 P
2. 90% YS
PRD Pressure relief requirement …not higher than (2)
50 PSIG or above 10% above test pressure
initial pressure of relief (PRD) pressure
gradually increase to 1/2 test pressure or 25 psig (lessor)
when to use sensitivity leak test
when joint cannot be view during other leaks test (hydro/pneumatic)
sensitive leak test pressure?
lessor of 15 PSIG or 25% of DP
when to inspect pneumatic test?
at design pressure , increase to test pressure and then decrease to DP to inspect
sensitivity shall be less than
10^-3 atm-ml/sec
joints cannot be painted during ____test?
sensitive test (ok for pneumatic)
when is it allowed to perform a hydro test at less than the pressure calculated by 1.5P (St/S)
when piping cannot be isolated from a vessel and the piping hydro test pressure exceeds the vessel test pressure
when is impact test not required?
when MDT is ABOVE the min temp
Impact test SR .3 or less , lowest MDT
max is -155F
impact test SR .3 or more lowest MDT
max is -55F
charpy v notch applicable specs/procedure is always
ASTM A370 AND product form
charpy acceptance
one specimen can be below the average value
no specimen can be below the min value
add 2x the corrosion if process is on both sides of the….
blank
preheating applies to
ALL types of welding (tack , repair welds)
preheat zone should be (for B31.3)/(API570)
larger 3” or 1.5x normal thickness
/
extend at least 2in on either side
preheat may not be considered as an alternative to
Environmental cracking
pwht controlling thickness of a fillet weld is based on
throat
what is min preheat temp when performing LOCAL pwht in lieu of full encirclement PWHT
> > 300F
preheat to not les than 300F may be used in lieu of PWHT for alteration/repairs for what type P metal?
P1 and P3
local PWHT may be substituted for 360 banding if (3)
- > > 300F of high is maintained
- PWHT maintained for a distance of 2x the base metal thickness with min of 2 thermocouples
- PWHT is not for environmental cracking resistance
anchor/guide prevent movement
3/2 direction
flattening of bend should not exceed _of the nominal outside/inside diameter
8%/3%
welder performance qualification made for another employer can be approved
by the inspector
undercut
groove adjacent to the weld or toe
