BS 7910:1999
Withdrawn
A Withdrawn Standard is one, which is removed from sale, and its unique number can no longer be used. The Standard can be withdrawn and not replaced, or it can be withdrawn and replaced by a Standard with a different number.
A Withdrawn Standard is one, which is removed from sale, and its unique number can no longer be used. The Standard can be withdrawn and not replaced, or it can be withdrawn and replaced by a Standard with a different number.
Guide on methods for assessing the acceptability of flaws in metallic structures
Hardcopy , PDF
30-11-2018
English
01-10-2000
Committees responsible
Foreword
Introduction
1 Scope
2 Normative references
3 Symbols and definitions
4 Types of flaw
5 Modes of failure and material damage mechanisms
6 Information required for assessment
7 Assessment for fracture resistance
8 Assessment for fatigue
9 Assessment of flaws in plant operating at high
temperatures
10 Assessment for other modes of failure
Annexes
A (normative) Evaluation under combined direct and
shear stresses or mode I, II and III
loads
B (informative) Assessment procedures for tubular
joints in offshore structures
C (informative) Fracture assessment procedures for
pressure vessels and pipelines
D (normative) Stress due to misalignment
E (normative) Flaw re-characterization
F (informative) A procedure for leak-before-break
assessment
G (normative) The assessment of corrosion in pipes and
pressure vessels
H (normative) Reporting of fracture, fatigue or creep
assessments
I (informative) The significance of weld strength
mismatch on the fracture behaviour of
welded joints
J (informative) Use of the results of Charpy V-notch
impact tests to indicate fracture
toughness levels
K (normative) Reliability, partial safety factors,
number of tests and reserve factors
L (normative) Fracture toughness determination for
welds
M (normative) Stress intensity factor solutions
N (normative) Simplified procedures for determining
the acceptability of a known flaw or
estimating the acceptable flaw size
level 1 fracture procedures
O (informative) Consideration of proof testing and warm
prestressing
P (normative) Calculation of reference stress
Q (informative) Residual stress distributions in
as-welded joints
R (normative) Determination of plasticity interaction
effects with combined primary and
secondary loading
S (normative) Approximate numerical integration
methods for fatigue life estimation
T (informative) Information for making high temperature
crack growth assessments
U (informative) Worked example to demonstrate high
temperature failure assessment procedure
Bibliography
FIGURES
1 Linearization of stress distributions
2 Schematic representation of stress distribution
across section
3 Procedure for resolving flaws normal to principal
stress
4 Flow chart - General methods
5 Flow chart - Level 1
6 Flow chart - Level 2
7 Flow chart - Level 3
8 Flaw dimensions
9 Planar flaw interactions
10 Level 1 FAD
11 Level 2 FADs
12 Level 3C FAD with assessment locus for a known flaw
13 Example of non-unique solutions (schematic)
14 Schematic crack growth relationships
15 Recommended fatigue crack growth laws
16 Quality category S-N curves
17 Assessment of surface flaws in axially-loaded
material for simplified procedure
18 Assessment of surface flaws in flat material
(no weld toe or other stress raiser) in bending for
simplified procedure
19 Assessment of embedded flaws in axially-loaded
joints for simplified procedure
20 Assessment of weld toe flaws in axially-loaded
joints for simplified procedure
21 Assessment of weld toe flaws in joints loaded in
bending for simplified procedure
22 Determination of the temperature Tc at which 0.2%
creep strain is accumulated at a stress level equal
to the proof strength
23 Determination of the time t(T) to achieve an
accumulated creep strain of 0.2% at a stress level
equal to the proof strength
24 Schematic behaviour of crack subjected to steady
loading at elevated temperature
25 Schematic representation of crack propagation and
failure conditions
26a Flow chart for overall creep assessment
27 Schematic diagrams of typical relationships between
crack velocity and stress intensity factor during
stress corrosion cracking
28 Types of corrosion fatigue crack growth behaviour
B.1 Assessment methodology for fatigue crack growth in
tubular joints
C.1 Algorithm for pressure vessel flaw assessment
E.1 Re-characterization of flaws for ligament failure
by ductile mechanisms under dynamic loading
F.1 The leak-before-break diagram
G.1 Flow chart of assessment procedure
J.1 Flow chart for selection of appropriate correlation
K.1 Evaluation of F L for single primary stress
M.1 Through-thickness flaw geometry
N.1 Relationship between actual flaw dimensions and the
parameter for surface flaws
O.1 Typical warm prestress cycles
Q.1 Typical residual distributions in welded joints
R.1 Values for P1 for defining Kr
T.1 Derivation of strain versus time curves from
iso-strain curves
U.1 Flaw dimensions
TABLES
1 Limits for slag inclusions and porosity
2 Procedure for assessment of known flaws
3 Stress ranges used in fatigue assessments
4 Recommended fatigue crack growth laws for steels
in air
5 Recommended fatigue crack growth laws for steels
in a marine environment
6 Recommended fatigue crack growth threshold, values
for assessing welded joints
7 Details of quality category S-N curves
8 Minimum values for assessing non-planar flaws and
shape imperfections
9 Limits for non-planar flaws in as-welded steel and
aluminium alloy weldments
10 Limits for non-planar flaws in steel weldments
stress relieved by PWHT
11 Acceptance levels for misalignment expressed in
terms of stress magnification factor Km
12 Acceptance levels for weld toe undercut in material
thickness from 10 mm to 40 mm
13 Temperature below which creep is negligible in
200 000h
D.1 Formulae for calculating the bending stress due to
misalignment in butt joints
F.1 Guidance on selection of assessment sites around a
pipe system
J.1 Estimation of T27j from Charpy energies measured at
other temperatures
K.1 Target probability of failure (events/year)
M.1a Mm* for axial through-thickness flaws in cylinders
- Pressure loading
P.1 Values of x for bending loading
Q.1 Parametric ranges for recommended residual stress
distributions
R.1 Tabulation as function of Lr and Kps /(K1p/Lr)
T.1 Constants used to derive creep crack propagation
rates in mm/h
U.1 Operating conditions
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