NFE83-100-1
NF E83-100-1
1995-12
Ce document est à usage exclusif et non collectif des clients Normes en ligne.
Toute mise en réseau, reproduction et rediffusion, sous quelque forme que ce soit,
même partielle, sont strictement interdites.
This document is intended for the exclusive and non collective use of AFNOR Webshop (Standards on line) customers. All network exploitation, reproduction and re-dissemination, even partial, whatever the form (hardcopy or other media), is strictly prohibited.
Boutique AFNOR
Pour : CONVERTEAM SAS
Client 4735900
Commande N-20100723-417518-TA
le 23/07/2010 02:07
? AFNOR 1995AFNOR 19951st issue 1995-12-F
? A F N O R 1995 — A l l r i g h t s r e s e r v e d FE038722ISSN 0335-3931NF E 83-100-1December 1995Classification index:
E 83-100-1French standard French standard approved by decision of the Director General of AFNOR on November 20, 1995, taking effect on December 20, 1995.Replaces the approved standard with the same index dated December 1987.Correspondence When this document was published, there were no international works dealing with the same subject.
Analysis This document forms part of a series of normative documents concerning the
construction of fabricated assemblies.
This part defines especially:
—the terminology;
—welding classes and quality;
—the extent of inspections and the degree of aptitude of welders and operators.This document gives in its annexes recommendations for fatigue analysis of welded
assemblies, as well as the examples of welding quality class determination, for
informational purposes.
Descriptors Technical International Thesaurus: welding, quality classes, inspection, welders
(personnel), qualification, fatigue tests, computation.
Modifications
With respect to the previous edition, taking into account of the standards NF EN 287-1, NF EN 288-1 and the following.
Corrections
NF E 83-100-1—2—
Contents
Page Foreword (3)
1Scope (3)
2Normative References (4)
3Definitions (4)
4Welding quality class (11)
4.1Definition of welding quality class (11)
4.2Risks encountered in case of the weld’s failure (11)
4.3Types of operational stresses of welded joints (12)
4.4Choice of welding quality classes (13)
5Extent of the inspections (14)
5.1General case (14)
5.2Extent of the supplementary inspections (14)
6Bibliography (15)
Annex A (informative) Recommendations for the fatigue analysis of welded assemblies (16)
A.1General Remarks (16)
A.2Fatigue tests on welded assemblies (18)
A.3Calculation rules (22)
A.4Example of application (34)
Annex B (informative) Examples of welding quality class determination (37)
—3—NF E 83-100-1
Foreword
1)This document forms the first part of a series of normative documents grouped under the same index E 83-100 concerning the welding techniques relating to the construction of fabricated assemblies, of which the outline is the following:
—Part 1: General remarks: terminology, weld quality classes, extent of weld inspections
—Part 2: Materials — Design
—Part 3: Guide for the choice of materials and for constructive provisions
—Part 4: Manufacturing — Inspection
—Part 5: Qualification of a welding operational procedure
This collection of normative documents corresponds to the needs expressed by the different concerned professions in order to facilitate the manufacturer-client relationships. In particular, it allows one to:
—unify the language in this domain;
—unify the welding specifications required by the different order-givers;
—define for each welded joint, a level of reliability corresponding to the use requirements;
—serve as reference at the implementation of provisions relating to welding within the framework of quality assurance.
2)While waiting for elasticity criteria to be brought into line with national and European standards and taking into account the fact that the symbol R e has no meaning in European standards, the following measures are adopted in this document on the subject of the elastic limit:
—the elastic limit to take into account is the upper flow limit R eH (generally specified in the EN standards), or, in its absence, the conventional elastic limit at 0.2% (R p0.2), or the extension limit at 0.5% (R t0.5). In case of dispute, the conventional elastic limit at 0.2% (R p0.2) must be determined;
—the limit specified in this document is the upper flow limit (R eH); if one does not have guaranteed R eH values, one can use the guaranteed values of R p0.2 or R t0.5, all the while maintaining the specified limits.
1Scope
This document defines, within the framework of construction and repair of fabricated assemblies relating to its scope of application:
—the terminology of the terms most commonly used;
—welding quality classes;
—the extent of inspections and the degree of aptitude of welders and operators according to welding quality classes.
It gives in its annexes for informational purposes the recommendations for fatigue analysis of welded assemblies, as well as examples of welding quality class determination.
This document applies to the construction of fabricated assemblies in steel relating to mechanical industries, such as, for example, those concerning mechanical parts, machine frames, mining materials, agricultural machinery, handling gear, etc., with the exception of those that are subject to special standards or regulations, especially pressure devices, hoist devices and certain handling devices.
It does not apply to metallic construction (fixed or mobile framing and metallic structures, included in a building operation, civil engineering, public works, facilities and equipment).
NF E 83-100-1—4—
2Normative References
This document incorporates by dated or undated reference, provisions from other publications. The normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this document only when they have been incorporated into it by amendment or revision. For undated references, the last edition of the publication referred to applies.
NF EN 287-1, Qualification test of welders — Fusion welding — Part 1: Steels (classification index: A 88-110-1). NF EN 288-1, Specification and approval of welding procedures for metallic materials — Part 1: General rules for fusion welding (classification index: A 89-010-1).
NF A 03-400, Iron and steel — General principles of the fatigue test.
NF E 83-100-4, Construction of fabricated assemblies — Welding processes — Part 4: Manufacture Inspection.
3Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
buyer
The buyer is the physical or legal person who buys from the manufacturer a fabricated assembly, either on his own behalf or on the behalf of a third party.
It is up to the buyer to indicate, under his own responsibility, the data necessary for the requested construction and, if the need arises, special requirements in addition to those in this document.
3.2
welded assembly
A welded assembly is a group of elements assembled by using one or several welds.
3.3
welding quality class
A welding quality class establishes the conditions necessary and sufficient to be required at design and to be respected at manufacturing in order to obtain an assembly capable to support the stresses from use and those that can result from manufacturing without damage.
3.4
designer
The designer defines, on behalf of the manufacturer or the purchaser, the product, its conditions of use, its characteristics, and drafts the technical specifications accompanying the order.
The designer may work for the manufacturer’s or the purchaser’s own operation.
3.5
manufacturer
The manufacturer is the physical or legal person who assumes the responsibility for the fabricated construction, in accordance to the specifications provided by the purchaser.
The manufacturer may entrust the operations or work to subcontractors but maintains complete liability of the operations or work thus subcontracted.
3.6
fabricated construction
Group that is part of a fabricated construction (machines, installations, etc.) constituted of one or several welded assemblies.
—5—NF E 83-100-1 3.7
supplementary inspection
A supplementary inspection is an inspection intended to assess the quality of the weld on both sides of an anomaly outside of the detected tolerance during an inspection.
3.8
inspector
Physical person responsible for performing the inspection operations.
This person may answer to the manufacturer, the purchaser, or to a specialized outside organization, following the agreement in the order.
3.9
test plate
Representative specimen welded at the same time and with the same parameters as the welded joint to be assessed. This plate may be adjoining or not to that of the welded joint, or be sampled directly on the part, in the joint itself.
3.10
thinning by heat
Before welding, the action of bringing the parts to a temperature less than 100°C in the interest either of drying them, or of bringing them to a temperature sufficient for welding in the case of parts that are too cold.
3.11
welder’s degree of aptitude (see standard NF E 83-100-4)
Qualification level obtained by a welder at a given qualification test.
3.12
stress relieving (relaxation treatment)
Thermal or mechanical treatment intended to diminish the internal stress of the weld.
3.13
extent of non-destructive testing
The extent of non-destructive testing is, for a welded joint, the weld length proportion to be inspected.
3.14
weld throat thickness
3.1
4.1
nominal throat thickness
The nominal throat thickness "a" is the thickness of the weld (or reference throat thickness) used for the calculation.
The figures of table 1 (see the end of this clause) define the nominal throat thicknesses of the most common welded assemblies for welds with or without chamfer.
3.1
4.2
actual throat thickness
The actual (or real) throat thickness "a u" is the effective throat thickness obtained after welding.
3.15
gouging
Operation intended to eliminate irregularities, defects, possible slag deposits to leave only the sound metal before restart, on a weld bead.
3.16
inspector
Physical person entrusted by the purchaser with supervising manufacturing and/or inspection operations.
NF E 83-100-1—6—
3.17
joint
Space between two or several elements to be assembled by welding whose edges have been prepared for this purpose (see figure 1).
In the case where the edges are straight, the joint volume may be null.
Primary metal
αAngle of chamfer
g Space or play
s Lock or flat spot
Figure 1
3.18
welded joint or weld
The term welded joint, or weld, indicates the joint after making the weld (see figure 2).
Consumable metal
Molten metal Welded joint
Figure 2
3.19
welding operational procedure (see standard NF EN 288-1).
3.20
welding operator (see standard NF EN 287-1).
3.21
preheating
Before welding, the action of bringing parts to be assembled to a determined temperature and maintaining the parts at this temperature for the entire duration of the welding.
3.22
post-heating
After welding, the action of maintaining the assembled parts at a determined temperature and for a given time, and cooling them.
3.23
welding procedure (see standard NF EN 288-1).
3.24
welding program or descriptive of a welding operational procedure (DWOP) (see standard NF EN 288-1).
—7—NF E 83-100-1 3.25
welder qualification (see standard NF E 83-100-4).
3.26
root
Region of the first run furthest from the welder.
3.27
repair
Important operation applied to a fabricated construction before or after implementation, in the interest of making it conform to the previously defined quality criteria.
3.28
resumption (not to be confused with touch-up or sealing run)
Continuing a weld after a stop.
3.29
sealing run
Operation performed to the back side of a weld for full penetration in the interest of improving its finish and/or resistance.
3.30
touch-up
Local operation performed in the interest of eliminating minor defects detected in the welded assemblies, before implementation.
3.31
inspection severity
Inspection requirements determined according to the welding quality classes.
3.32
welder (see standard NF EN 287-1).
3.33
weld (see welded joint).
3.34
partial penetration weld
Welding concerning only one part of the thickness of at least one of the assembled elements; the penetration may be normal or strong, according to the depth of the molten zone in the primary metal.
3.35
guaranteed penetration weld
Welding performed by one (or several) procedure(s), in specified conditions, assuring the sure connection of the assembled elements over a definite depth.
3.36
full penetration weld
Welding performed by one (or several) procedure(s), in specified conditions, assuring the sure connection of the assembled elements over the thickness of at least one of the assembled elements.
3.37
welding with natural chamfer
Welding performed in a joint whose chamfer is constituted by the rounding or the angle of the parts to be assembled.
3.38
support
Device (metallic strip, fibreglass, ceramic, flux, etc.) supporting the metal in fusion during welding.
NF E 83-100-1—8—
Table 1: Nominal throat thicknesses of the most common welded assemblies
for welds with or without chamfer
Designation Schematic representation
1 — partial penetration
(normal penetration) angle weld
without chamfer
2 — partial penetration
(normal penetration) angle weld
with chamfer
3 — partial penetration
(strong penetration) angle weld
without chamfer
4 — partial penetration
(strong penetration) angle weld
with chamfer
(to be continued)
—9—NF E 83-100-1
5 — full penetration angle weld with or without chamfer
6 — full penetration angle weld
with chamfer
7 — strong inclination angle
weld
—open angle:
strong penetration weld
—closed angle:
normal penetration weld
(to be continued)
Table 1: Nominal throat thicknesses of the most common welded assemblies
for welds with or without chamfer (continuation)
Designation Schematic representation
NF E 83-100-1—10—
8 — welding with natural chamfer
9 — partial penetration
(normal penetration) angle weld
with chamfer
10 — partial penetration
(strong penetration) butt weld
with chamfer
(to be continued)
Table 1: Nominal throat thicknesses of the most common welded assemblies
for welds with or without chamfer (continuation)
Designation Schematic representation
—11—NF E 83-100-1
4
Welding quality class 4.1Definition of welding quality class
4.1.1In use, the welded joints of a fabricated assembly is subjected to various stresses according to their destination, their placement, etc.
Otherwise, the failure of a welded joint can have different consequences according to the risks encountered and the conditions for replacing the defective element.
In order to optimise the manufacturing according to these conditions, this document establishes for welded joints,by order of decreasing severity, three welding quality classes A, B and C (see 4.4), which are determined accordingly:
—risks encountered in case of failure of the weld (see 4.2);
—operational stresses of the welded joint (see 4.3).
A same fabricated structure can therefore include different welding quality classes.
4.1.2The quality class of each of the welds is defined at the time of design
It determines:
—the extent of the inspections;
—the severity of the inspections;
—the degree of aptitude of welders and operators;
—the welding program;
—the particular conditions to be respected during manufacturing and inspection.
4.2Risks encountered in case of the weld’s failure
Table 2 establishes three grades of risks according to the consequences of a failure during operation:
?
R1 = significant risks;?
R2 = risks of medium significance;?R3 = low risks.
The grades of risks must be determined from one or several criteria from table 2 and must be adapted to the environmental conditions in which the fabricated structure is located.11 — full penetration butt weld with chamfer
Table 1: Nominal throat thicknesses of the most common welded assemblies
for welds with or without chamfer (continuation)
Designation
Schematic representation
(end)
NF E 83-100-1—12—
4.3Types of operational stresses of welded joints
Fabricated assemblies are classified according to stresses to which they are subjected. One differentiates:—non-calculated assemblies;
—the calculated assemblies not subjected to a fatigue analysis;
—the calculated assemblies subjected to a fatigue analysis.
NOTE For the definitions and symbols used in this clause, refer to the standard NF A 03-400.
4.3.1Calculated assemblies not subjected to a fatigue analysis (determinant static loads)
These assemblies are designed and calculated to resist static loads, which are:
—structures subjected to essentially static loads;
—structures and constructions for which, in addition to static loads, variable loads produce a stress spectrum for which one can presuppose that fatigue shall not be a decisive factor.
One considers that a weld is not to be calculated and/or verified in fatigue if the number of cycles is equal or inferior to the following value:
where :
N
is the number of cycles stipulated for the lifespan of the structure;is the extent of stress applied in megapascals ( = σmax – σmin calculated at the limit state of use);m
is equal to 3 (the most usual coefficient).4.3.2Calculated assemblies not subjected to a fatigue analysis (determinant cyclic loads)
4.3.2.1These assemblies are designed and calculated to resist stress of periodically variable intensities (estimated number of cycles), of which the maximum level remains inferior to the metal’s elastic limit.
4.3.2.2The cyclic load is evaluated according to the ratio:
where
is the extent of the applied stresses:is the extent of the admissible stresses.
Table 2: Grades of risks according to the consequences of a failure in operation
and replacement conditions of the defective element Grades of risks Defect in use Necessity of the replacement
or repair of the defective element
Condition of replacement or repair of the defective element Repair on site Requiring immediate stop Not requiring immediate stop Immediate Deferred
Difficult Easy Impossible or difficult
Easy Short
duration Long duration R1X X X X
R2X X X
X
R3X X X X N 71010
×σm ?---------------------≤σ
?σ?σ?σ?a
---------σ
?σ?a
—13—NF E 83-100-1
This extent depends on the type of assembly (see table A.1 of the annex A which gives recommendations for fatigue analysis of the welded assemblies).
4.3.2.3In the case where the extent of stresses varies over the use of the structure, a verification must be performed using the Miner rule (see annex A).
If the load is of a random character, a treatment for obtaining a load cumulative must be performed prior to the application of this rule.
4.3.3Non-calculated assemblies
These assemblies are designed and dimensioned by comparison according to experience.
These are assemblies for which it is not possible, or not necessary, to calculate the stresses and the variation of the applied forces. They are classified in "stressed" or "low stressed" assemblies.
4.4Choice of welding quality classes
Table 3 gives, according to the grades of risks defined in paragraph 4.2 and operational stresses of joints defined in paragraph 4.3, the corresponding welding quality classes A, B an C.
When an assembly is subjected to determinant cyclic loads and elevated static loads, the most severe welding quality class must be applied but when an assembly is subjected to severe cyclic loads, the angle weld profile determines its performance in use. This superior quality accessible by a qualified welder is defined in paragraph
6.4 of the standard NF E 83-100-4.
Annex B gives examples of welding quality class determination.
Table 3: Choice of welding quality Operational stresses of welded joints Welding quality classes
according to grades of risks
R1
R2R3Calculated assemblies
not subjected
to a fatigue analysis 1)
(determinant static loads)Static stresses A A B A B C B C C Calculated assemblies
subjected
to a fatigue analysis 1)
(determinant cyclic loads)Cyclic stresses A A B A B C B C C Non-calculated assemblies
Stressed A A B Low stressed A B C
= calculated factored stress.= stress at the conventional elasticity limit.= Extent of applied stresses.= Extent of admissible stresses at 2 × 106 cycles (see annex A).
1) The fatigue analysis does not exclude static testing; apply the most severe.
0,8σc σe
-----1≤≤0,4σc σe
-----0,8≤≤σc σe
-----0,4<0,7σ?σa
?---------1≤≤0,3σ?σa
?---------0,7≤≤σ?σa
?---------0,3<σc
σe
σ?σa ?
NF E 83-100-1—14—
5Extent of the inspections
5.1General case
Table 4 establishes for each welding quality class:
—the extent of inspections of density and surface.
The data appearing in table 4 applies to a fabricated assembly.
In the case of mass-manufactured fabricated assemblies, the percentage of fabricated assemblies to be inspected is defined by agreement between the designer and the manufacturer.
For lack of the ability to apply the inspections stipulated in table 4 in the correct conditions of execution and interpretation, an inspection of welds must be performed during manufacturing according to the methods to be defined in accordance with the designer.
Table 4
Extent of the inspections
Welding quality class
Visual Radiography or ultrasound Magnetoscopy or penetrant testing A100> 50% 1) 2) 3)> 50% 1)
B100—> 10% 4)
C100——
1) By agreement between the manufacturer and the purchaser, inspection by radiography or ultrasound may be
replaced with an inspection by magnetoscopy or by penetrant testing and vice versa.
2) For angle assemblies, the inspection by ultrasound is replaced by inspection by magnetoscopy or by
penetrant testing if the thickness is less than or equal to 10 mm.
3) The stress concentration points (nodes, crossings, weld extremities,...) are inspected at 100% over at least
50 mm on both sides of the concentration axis or of the edge of the welded joint.
4) Inspection by magnetoscopy or by penetrant testing is cancelled on steels whose elastic limit is less than
355MPa, if the thickness "t" or the throat thickness "a" is less than or equal to 20 mm.
REMARKS: The inspections performed must be distributed as regularly as possible over the whole of each
relevant welded joint from the same welding quality class.
The inspected length must not be less than 400 mm.
Any welded joint of a length less than 400 mm is inspected over the total length.
For welded joints of a length greater than 400 mm, all the extremities must be inspected over a length at least
equal to 50 mm.
5.2Extent of the supplementary inspections
In case of surpassing the limit of acceptance, the initial inspection is extended on both sides of the zone in question over a minimum length of 400 mm.
During this complementary inspection, if the acceptance limit is once again surpassed, the inspection is then extended to the total length of the assembly.
—15—NF E 83-100-1
6Bibliography
NF E 52-109-1, Lifting and handling — Welded joints — Part 1: Fabrication.
NF E 52-109-2, Lifting and handling — Welded joints — P art 2: Weld quality classes — Extent of the non-destructive testing.
NF P 22-470, Steel construction — Welded connections — Details and design of welds.
Document IIS/IIW-693/81, Recommendations for the calculation of steel welded constructions, subject to cyclic stresses.
NOTE This document of the International Welding Institute should soon be revised.
A further revision of this document (annex A) is stipulated so that this remains coherent with the IWI document.
Terms and definitions used in welding and associated techniques (publications of Autogenous Welding and of the Welding Institute).
NF E 83-100-1—16—
Annex A
(informative)
Recommendations for the fatigue analysis of welded assemblies 1)
This annex gives the rules relating to performance in fatigue of welded assemblies.
These rules based essentially on the tests can be used for the design and calculation of welded assemblies.
A.1General Remarks
Any welded assembly is the seat of stress concentrations which occur at very different steps.
The first effect concerns the general welding melting rate (figure A.1) that one finds evoked by the inspection specifications (elimination of excessive rounding for butt welding, recommendation of a flat angle or concave weld). It is a question of an effect of macrogeometry (at the scale of the weld bead).
Figure A.1
One then finds a microgeometry effect. It is a question in this case of very localized stress concentrations only concerning the particular zones of a weld (figure A.2):
—connecting zone of a butt weld;
—toe and root of a angle weld.
Figure A.2
It’s in these regions that what one usually qualifies as natural weld notches are located.
1)Text drafted from the document IIS/IIW-693/81.
Strongly curved weld (to be avoided) Concave weld Convex weld (to be avoided)
Connection
Root
Weld toe angle
—17—NF E 83-100-1
Finally, the third effect results in the geometry of the whole, i.e. the related arrangement of the layout of the parts to be assembled (figure A.3).
Figure A.3
The most important effect regarding fatigue seems to be the effect of microgeometry because the fatigue cracks are preferentially located in the regions where it occurs. (Figure A.4 gives examples of cracks for informational purposes.)
Figure A.4
In reality, the combination of three geometric effects condition the localization of the cracks, the microgeometric effect playing a predominant role.
Even if, as indicated below, this observation cannot be used quantitatively, it is, however, a question of extremely
precious qualitative information.
Crack Crack
Crack
Crack
Crack
Direction of the force
NF E 83-100-1—18—
A.2Fatigue tests on welded assemblies
A.2.1Test principle
The fatigue tests on welded assemblies resume the general principles of fatigue tests (see standard NF A 03-400). As a general rule, the tests are conducted with non-random simple cycles. Only the side effects of geometric imperfection bring a complication to the practical realisation of pure loading systems. On the other hand, the fact of working on specimens taken from large-sized welded plates must cause an alteration of the field of residual stresses and an almost complete disappearance of the effect of global geometry, although it is always useful to confirm the results on small specimens through tests on parts or on real-size models.
A fatigue test on a welded specimen is to be performed in the following way (see figure A.5):
Figure A.5
It concerns a repeated tensile test (Rσ = σmin / σmax = 0), for which one imposes a force variation ?F(?F=F max–F min). By definition, the butt assembly is subjected to an extent of variation of nominal stress ?σequal to ?F / S.
This magnitude ?σ is equal to σmax – σmin ; it is designated hereafter in the text by "Extent of stress".
At the end of a certain number of cycles, a crack appears in the connection zone. Initiation occurs in the zone where the geometry is the most unfavourable and corresponds thus to the maximum notch effect; but, if the weld is regular, one sees very often multiple initiation which produces a continuous shallow surface crack. Continuing the test, one causes the propagation of the crack which generally occurs at depth, i.e. in the thickness of the product or in the thickness of the weld (see figure A.4) continuing until the specimen breaks.
A.2.2Choice of a representation of the results
Although on first thought, one can choose to represent the fatigue test results on the welded assemblies in any representation system, it’s the W?hler curve traced in a system of bilogarithmic coordinates (figure A.6) which is the most frequently used.