SIST EN 4678:2011

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aeronavtika - Varjeni in trdo spajkani sestavi za konstrukcije v aeronavtiki - Spoji kovinskih materialov pri varjenju z laserskim snopom - Kakovost varjenih sestavovLuft- und Raumfahrt - Schweiß- und Lötverbindungen für die Luft- und Raumfahrt - Lasers strahlschweißen - Qualität der SchweißverbindungenSérie aérospatiale - Assemblages soudés et brasés pour constructions aérospatiales - Assemblages de matériaux métalliques soudés par faisceaux laser - Qualité des assemblages soudésAerospace series - Weldments and brazements for aerospace structures - Joints of metallic materials by laser beam welding - Quality of weldments49.025.05Železove zlitine na splošnoFerrous alloys in generalICS:Ta slovenski standard je istoveten z:EN 4678:2011SIST EN 4678:2011en01-december-2011SIST EN 4678:2011SLOVENSKI
STANDARD



SIST EN 4678:2011



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 4678
July 2011 ICS 49.025.05 English Version
Aerospace series - Weldments and brazements for aerospace structures - Joints of metallic materials by laser beam welding - Quality of weldments
Série aérospatiale - Assemblages soudés et brasés pour constructions aérospatiales - Assemblages de matériaux métalliques soudés par faisceaux laser - Qualité des assemblages soudés
Luft- und Raumfahrt - Schweiß- und Lötverbindungen für die Luft- und Raumfahrt - Laserstrahlschweißen - Qualität der Schweißverbindungen This European Standard was approved by CEN on 9 July 2010.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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Management Centre:
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B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 4678:2011: ESIST EN 4678:2011



EN 4678:2011 (E) 2 Contents Page Foreword .31Scope .42Normative references .43Terms and definitions .64Symbols and abbreviations . 125Weldability . 126General requirements . 137Technical requirements for manufacturing new parts . 178Technical repair requirements . 319Special case . 31 SIST EN 4678:2011



EN 4678:2011 (E) 3 Foreword This document (EN 4678:2011) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2012, and conflicting national standards shall be withdrawn at the latest by January 2012. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. After enquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of ASD, prior to its presentation to CEN. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 4678:2011



EN 4678:2011 (E) 4 1 Scope This European Standard defines the rules to be observed to ensure the quality of aerospace structures in metallic materials by (solid reference number 521 and gas reference number 522 and diode laser Semi-conductor 523 according to EN ISO 4063) laser beam welding, implemented automatically, semi-automatically or manually. It is applicable without any restriction for the manufacturing of new parts or repair parts, these operations being under the responsibility of an approved design authority or repairer. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the reference document (including any amendments) applies. EN 1011-6, Welding — Recommendation for welding of metallic materials — Part 6: Laser beam weld EN 1435, Non-destructive examination of welds — Radiographic examination of welded joints EN 4179, Aerospace series — Qualification and approval of personnel for non-destructive testing EN 4632-001, Aerospace series — Welded and brazed assemblies for aerospace constructions — Weldability and brazeability of materials — Part 001: General requirements EN 4632-002, Aerospace series — Welded and brazed assemblies for aerospace constructions — Weldability and brazeability of materials — Part 002: Homogeneous assemblies aluminium and aluminium alloys EN 4632-003, Aerospace series — Weldability and brazeability of materials in aerospace constructions —Part 003: Welding and brazing of homogeneous assemblies of unalloyed and low alloy steels1) EN 4632-004, Aerospace series — Welded and brazed assemblies for aerospace constructions - Weldability and brazeability of materials — Part 004: Homogeneous assemblies highly alloyed steels Error! Bookmark not defined.) EN 4632-005, Aerospace series — Weldability and brazeability of materials in aerospace constructions — Part 005: Homogeneous assemblies of heat resisting Ni or Co base alloys Error! Bookmark not defined.) EN 4632-006, Aerospace series — Weldability and brazeability of materials in aerospace constructions — Part 006: Homogeneous assemblies of titanium alloys Error! Bookmark not defined.) ISO 857-1, Welding and allied processes — Vocabulary — Part 1: Metal welding processes EN ISO 4063, Welding and allied processes — Nomenclature of processes and reference numbers (ISO 4063:2009, Corrected version 2010-03-01) EN ISO 4136, Destructive tests on welds in metallic materials - Transverse tensile test (ISO 4136:2001) ISO 4969, Steel — Macroscopic examination by etching with strong mineral acids EN ISO 5173, Destructive tests on welds in metallic materials - Bend tests (ISO 5173:2009)
1) Published as ASD-STAN Prestandard at the date of publication of this standard by Aerospace and Defense Industries Association of Europe-Standardization (ASD-STAN), (www.asd-stan.org).
SIST EN 4678:2011



EN 4678:2011 (E) 5 EN ISO 6520-1, Welding and allied processes — Classification of geometric imperfections in metallic materials — Part 1: Fusion welding (ISO 6520-1:2007) EN ISO 6947, Welding and allied processes - Welding positions (ISO 6947:2011) EN ISO 9015-2, Destructive tests on welds in metallic materials - Hardness testing - Part 2: Microhardness testing of welded joints (ISO 9015-2:2003) EN ISO 9016, Destructive tests on welds in metallic materials - Impact tests - Test specimen location, notch orientation and examination (ISO 9016:2001) EN ISO 11145, Optics and photonics — Lasers and laser-related equipment — Vocabulary and symbols (ISO 11145:2006) EN ISO 14731, Welding coordination — Tasks and responsibilities (ISO 14731:2006) EN ISO 15609-4, Specification and qualification of welding procedures for metallic materials — Welding procedure specification — Part 4: Laser beam welding (ISO 15609-4:2009) EN ISO 15616-1, Acceptance tests for CO2-laser beam machines for high quality welding and cutting — Part 1: General principles, acceptance conditions (ISO 15616-1:2003) EN ISO 15616-2, Acceptance tests for CO2-laser beam machines for high quality welding and cutting — Part 2: Measurement of static and dynamic accuracy (ISO 15616-2:2003) EN ISO 15616-3, Acceptance tests for CO2-laser beam machines for high quality welding and cutting — Part 3: Calibration of instruments for measurement of gas flow and pressure (ISO 15616-3:2003) ISO 17636, Non-destructive testing of welds — Radiographic testing of fusion-welded joints ISO 17639, Destructive tests on welds in metallic materials — Macroscopic and microscopic examination of welds EN ISO 17640:2,
Non-destructive testing of welds - Ultrasonic testing - Techniques, testing levels, and assessment (ISO 17640:2010) ISO 22826, Destructive tests on welds in metallic materials — Hardness testing of narrow joints welded by laser and electron beam (Vickers and Knoop hardness tests) EN ISO 22827-1, Acceptance tests for Nd:YAG laser beam welding machines — Machines with optical fibre delivery — Part 1: Laser assembly (ISO 22827-1:2005) EN ISO 22827-2, Acceptance tests for Nd:YAG laser beam welding machines — Machines with optical fibre delivery — Part 2: Moving mechanism (ISO 22827-2:2005) ISO 24394, Welding for aerospace applications — Qualification test for welders and welding operators — Fusion welding of metallic components ISO/TR 25901, Welding and related processes — Vocabulary NAS 410, Certification and qualification of non-destructive test personnel 2)
2) Published by: National Standards Association, Inc., 1200 Quince Orchard Blvd, Gaithersburg, MD 20878, United States. SIST EN 4678:2011



EN 4678:2011 (E) 6 3 Terms and definitions For the purposes of this document, the following terms and definitions given in ISO 857-1 and EN ISO 11145 standards apply. 3.1 General 3.1.1 Laser beam welding Fusion welding process (using radiation) in which the heat required for the fusion is provided by the coherent and monochromatic light emitted by a laser focused by an optical system either:  solid (FLS or 521 according to EN ISO 4063);  Example: YAG: (Yttrium Aluminium Garnet) doped with neodymium. The wavelength λ of corresponding radiation is 1,06 µm; or  gas (FLG or 522 according to EN ISO 4063);  Example: CO2 wavelength λ of corresponding radiation is 10,6 µm;  Diode laser welding (Semi-conductor laser welding or 523 according to EN ISO 4063). The word laser is the acronym for "Light Amplification by Stimulated Emission of Radiation". 3.2 Technical terms 3.2.1 Welding parameters 3.2.1.1 Run-on or run-off plates See ISO/TR 25901. NOTE This interval is measured on the detail parts, positioned in their welding setup, and is used as a reference to determine the minimum width of the weld zone. 3.2.1.2 Beam shift Deviation of beam position compared with the effective position of joint plane in certain heterogeneous welds (materials and/or dissimilar thicknesses).
3.2.1.3 Firing distance Distance between the impact point of the beam on detail parts and a reference surface linked to the machine EXAMPLE End of nozzle. 3.2.1.4 Specific welding energy Ratio between the beam power over the welding speed, multiplied by 60. Paverage (W) is measured at nozzle exit side.
J/cm)(k(cm/min)000160)(averageaverageVWPE××= SIST EN 4678:2011



EN 4678:2011 (E) 7 3.2.1.5 Slope (or ramp) down Operating conditions for which the depth of penetration differs in a decreasing manner according to a slope, a series of ramps or steps. NOTE Slope down occurs either according to time or distance, see Figure 1.
Figure 1 3.2.1.6 Slope (or ramp) up Controlled increase of the beam power at the beginning of the welding 3.2.1.7 Clearance before welding Distance measured on a straight section of the joint between the sides to weld. NOTE The clearance depends on the design of the welded joint (for circular axial welds or circular welds see EN 1011-6). 3.2.1.8 Focusing level Distance between the beam impact point on the detail parts and the focusing point. NOTE Conventionally, this distance is negative when the focusing point is within the detail parts, see Figure 2. SIST EN 4678:2011



EN 4678:2011 (E) 8
Key 1 Positive focusing level (+ 1 mm) 2 Focusing level 0 3 Negative focusing level (− 1 mm) 4 Firing distance 5 Detail part Figure 2 3.2.1.9 Beam power The laser beam power is measured with a calorimeter which absorbs all or part of the beam
3.2.1.10 Welding speed Length of the weld on beam impact side produced per time unit. 3.2.2 Other technical terms 3.2.2.1 Welding campaign Series of welding operations on identical parts, executed on the same machine, without any changes to adjustments, without performing other welds on the machine, without interrupting manufacturing for more than a week (working days). 3.2.2.2 Tacking pass Pre-assembling of elementary detail parts using the same process as the one used for welding, consisting of making slightly penetrating, narrow weld, continuous or discontinuous along the joint plane. The purpose is to maintain detail parts in position. SIST EN 4678:2011



EN 4678:2011 (E) 9 3.2.2.3 Adjustment verification specimen A flat or round test specimen of the same material, subjected to the same heat treatments as the detail parts, on which a melt run will be made in the middle using the parameters identical to those used for parts, and for which the relation between the micrographic shape of the cross section cut of the bead and that obtained on test specimens or real parts has been previously defined. 3.2.2.4 Structural state State of the crystalline metal structure 3.2.2.5 Manufacturing Execution of welding operations on new parts or parts being repaired 3.2.2.6 Stabilized manufacturing Manufacturing for which the reliability can be established without doubt over several welding campaigns, of which the number is previously defined by the design authority. 3.2.2.7 Smoothing pass or cosmetic pass Surface new fusion of the welded zone 3.2.2.8 Batch of parts Set of parts with the same reference from:  the same welding campaign;  the same heat treatment batch;  traceable material (processing, chemical analysis, etc). 3.2.2.9 Parent material Material or metal used to make the detail parts. 3.2.2.10 Filler material Additional alloy or metal used to make a weld of an assembly or a deposit. 3.2.2.11 Tooling Equipment required to hold and position parts before and during welding. 3.2.2.12 Detail part Individual element to be assembled with other elements to make up a complete part. 3.2.2.13 Part Assembly comprising several assembled detail parts. 3.2.2.14 Tack welding
Pre-assembly of detail parts by welding consisting of a set of tacks (by laser or an alternative process, for example TIG) along the joint plane, intended to hold the detail parts in position. SIST EN 4678:2011



EN 4678:2011 (E) 10 3.2.2.15 Pre-heating Heating of detail parts before welding without fusion. NOTE This operation may be carried out with an defocused beam or any other process. 3.2.2.16 Blind weld Case where the beam only crosses part of the thickness of the parts to be welded. 3.2.2.17 Qualification test specimen – Manufacturing test specimen  Test specimen representing manufactured parts to be welded under the same conditions as these parts;  Test specimen made from the same material grade, in the same structural state, with the same dimensions as the manufactured part. NOTE Manufacturing test specimens may be real parts. 3.2.2.18 Pool support Element positioned on detail parts to prevent the fused metal from overflowing. NOTE The material making up the pool support shall be of the same base alloy as the detail parts, to prevent any weld contamination. The pool support may be positioned as shown in Figure 3. Laser
Key 1 Pool support Figure 3 3.2.2.19 Heat treatment Treatment intended to provide the base material and the welded zone with the required characteristics and structural state 3.3 General terms 3.3.1 Customer
Individual or company placing a contract or order and who may or may not be the design authority. SIST EN 4678:2011



EN 4678:2011 (E) 11 3.3.2 Manufacturer
Person who makes, or manufactures and assembles the elements or subassemblies into assemblies.
3.3.3 Supplier Individual or company holding a contract or order that it has accepted, binding to the design authority of one company or to the final customer to perform the services defined therein. 3.3.4 Design authority The organisation responsible for the design of the welded assembly and for defining the performance and inspection requirements. 3.3.5 Welding coordinator Person responsible and competent to perform welding coordination according to EN ISO 14731. 3.3.6 Welder Person who is able to manipulate by hand the laser system and to manage the filler metal in the fusion pool and to develop the welding parameters. 3.3.7 Reinforced visual inspection Visual inspection of a surface with a magnifying glass, endoscope or other tests (dye penetrant or magnetoscopy, etc.). 3.3.8 Operator Person who operates adaptive control, automatic, mechanized, or robotic welding equipment. 3.3.9 Qualification Action recognizing that a welder, product, etc. is capable of fulfilling the role for which they are intended. 3.3.10 Repair Act consisting in making acceptable a part that was felt to be beyond the acceptance criteria after its normal manufacturing and inspection cycle NOTE Bringing into conformity of a part which had been damaged during operation 3.3.11 Setter Person in charge of the complete programming of the machine, beam analysis and finalization of welding procedure parameters and, if necessary, of performing welding operations using a mechanized or automated process.
3.3.12 Repairer Supplier in the repair activity domain. 3.3.13 Competent department Specialist service within a company with specific tasks. EXAMPLE Design office, quality service, laboratory, methods office. 3.3.14 Official supervisory body Approved government authorities or organizations responsible for checking the conformity of materials and welds with the definition file. SIST EN 4678:2011



EN 4678:2011 (E) 12 3.3.15 Welding procedure welding schedule specified course of action to be followed in making a weld, including the welding process(es), reference to materials, welding consumables, preparation, preheating (if necessary), method and control of welding and postweld heat treatment (if relevant), and necessary equipment to be used Redraft this definition. [ISO/TR 25901] 3.3.16 Welding procedure specification WPS document that has been qualified and provides the required variables of the welding procedure to ensure repeatability during production welding [ISO/TR 25901] 3.3.17 Non-destructive testing act of determining the suitability of some material or component for its intended purpose, using techniques that to do not affect its serviceability [ISO/TR 25901] NOTE Personnel shall be qualified in accordance with EN 4179/NAS 410. 4 Symbols and abbreviations GLW Gas Laser Welding SLW Solid state laser welding
P Welding power E Welding energy V Welding speed WPS Welding Procedure Specification 5 Weldability 5.1 Concept of weldability It is considered that a metallic material is weldable to a given degree, by a given process or for a given application type when, it can be used to produce a weld provided that precautions corresponding to this degree are taken, and if the characteristics and the consequences of the presence of the weld satisfy the required properties chosen as the basis for a judgement. 5.2 Weldability degrees Weldability of materials is assessed according to the following four degrees (see EN 4632-001):  degree 1: material with very good weldability, for which no special precautions are necessary. To be used in preference.  degree 2: material with good weldability but which may require special welding precautions (for example, preheating, low welding speed).  degree 3: material with poor weldability, requiring specific development for each part type and which may involve manufacturing uncertainties. Not to be recommended.  degree 4: material with very poor weldability. To be avoided. SIST EN 4678:2011



EN 4678:2011 (E) 13 6 General requirements 6.1 Weld classification
Weld classification is the responsibility of the design authority. 6.1.1 Manufacturing new parts
The design authority, at the time of part design, shall allocate a weld class to each joint: 1, 2 or 3 according to a decremental functional severity order. The requirements are listed in Table 1. A higher severity weld class may be allocated to meet specific problems such as manufacturing complexity or interpretation of inspection operations, etc.
Table 1 — Weld class allocation requirements Part with function Assembly weld rupture can alter normal operation of the part without significant consequences Safety critical 1 2 Other 2 3
A given part may have several different weld classes. Each weld class is associated with one of the following conditions:  implementation before manufacturing;  follow up during manufacturing;  inspection on welded assembly;  acceptance criteria. For weld classes 1 and 2, the design authority verifies with the quality department that the inspection operation makes it possible to guarantee compliance of the welds to the requirements of these classes. For class 1 welds, designs of lap welds, on raised edge or square-edged joint plane are not recommended (see sketch in Table 4). For classes 2 and 3 welds, overlapping welds on raised edges, on square-edged joint plane and with partial penetration joint are to be addressed in particular specifications. 6.1.2 Salvage The repairer shall comply with the recommendations of the design authority. However, if the acceptance criteria of this standard are selected due to the requirements of Clause 6, the repairer may propose a weld class. He shall then ask for the approval from the design authority or from the official supervisory body involved. SIST EN 4678:2011



EN 4678:2011 (E) 14 6.2 Welding machines The machines used for welding shall comply with EN ISO 15616-1, EN ISO 15616-2, EN ISO 15616-3, EN ISO 22827-1 and EN ISO 22827-2. In particular, machines shall have undergone specific qualification tests according to EN ISO 15616-1, EN ISO 15616-2 and EN ISO 22827-1 when they were acquired or renovated. 6.3 Operators, welders and setters 6.3.1 Training 6.3.1.1 Operator training For any manufacturing or repair operation, the laser beam-welding operator shall have followed a training course given by the competent department of the manufacturer (part manufacturer), or an external training organization, with regard to:  technical training on the process;  operation of the machine used (electrical power supply, etc.);  safety related to this machine and the welding operation;  equipment, instruments and tooling required for correct operation of the machine, and performance of the welding operation;  display and verification of welding procedures;  positioning of the focal point in relation to the part surface;  alignment check of the beam in relation to the joint plane;  appearance and geometrical check of welded assemblies. The operator shall weld beads and/or melt runs on standard parts and/or test specimens and/or manufacturing test specimens according to the validated welding procedure corresponding to his training. 6.3.1.2 Welder training Welders implementing the laser process by hand shall be able to manage the filler metal in a fusion bath and to develop the welding parameters. For any manufacturing or repair operation, the laser beam-welding operator shall have followed a training course given by the competent department of the manufacturer (part manufacturer), or an external training organization, with regard to:  technical training on the process;  operation of the machine used (electrical power supply, etc.);  safety related to this machine and the welding operation;  equipment, instruments and tooling required for correct operation of the machine, and performance of the welding operation;  display and verification of welding procedures;  positioning of the focal point in relation to the part surface;  alignment check of the beam in relation to the joint plane;  visual and geometrical inspection of welded assembly parts
 finalization of parameters and production of the necessary documents. SIST EN 4678:2011



EN 4678:2011 (E) 15 The welder shall weld beads and/or melt runs on standard parts and/or test specimens and/or manufacturing test specimens according to the validated welding procedure corresponding to his training. 6.3.1.3 Setter training For any manufacturing or repair operation, the laser welding setter shall have followed the operator and welder training course, as well as a theoretical and technical training course given by the competent department of the manufacturer (part manufacturer), and/or an external training organization.
The training concerns:  complete programming of the machine;  analysis of beam quality according to EN ISO 15616-1. For instance, use of a beam analysis device which enables to obtain the position, diameter of focal point and space distribution of energy;  finalization of parameters and production of the necessary documents; The setter shall prepare a welding procedure in order to validate his training. 6.3.2 Qualification 6.3.2.1 Operator and welder qualification
The examination on physical fitness (eyesight) of the operator and the welder will be realized in accordance with the test and requirements of the Table 2 hereafter or a test judged equivalent by the design authority.
Table 2 — Operator and welder qualification requirements Test Requirement Near vision Visual acuity (eyesight) shall be examined for near vision. Welder and Welding operators shall have vision acuity of 20/30 or better in each eye, and shall be able to read the Jaeger No. 2 eye chart at 400 mm or to pass an equivalent test as specified by an optometrist. Corrective vision may be used to fulfil eye test requirements Colour perception Be capable of distinguishing and differentiating colours used in the process involved. Where it is not possible to devise a suitable test, Ishihara test may be used.
Vision shall be tested to these requirements at least every two years. Operator and welder qualification shall comprise technical training on the process and production of a manufacturing test specimen, according to a given parameter welding procedure and have correctly produced at least one welded part. Guidance on operator and welder qualification is given in ISO 24394. Production of the manufacturing test specimen according to a given parameter welding procedure shall be renewed each time the operator has not welded for more than six months. Technical training on the process shall be repeated at least once every two years according to ISO 24394. Operator and welder qualification shall be the subject of a welding work quality follow up made by quality audit, based on conformance and periodic inspection operations carried out on standard production welds. SIST EN 4678:2011



EN 4678:2011 (E) 16 Operator and welder qualification shall be awarded by the competent department of the manufacturer, who will justify the training given and the results from test specimen manufacturing. The manufacturer shall verify the qualification of the operator and the welder, in accordance with the requirements of this standard or an equivalent standard acceptable to the design authority. Documented records shall be maintained. The supplier or repairer, if sub-contracting is involved, shall verify the qualification of operators and welders. Depending on the company, application of the following may be demanded:  this document;  a national document considered equivalent to the contents of this document;  an internal qualification procedure considered equivalent to the one described in this document. In case of a discrepancy or imperfections fully found, the responsibility of the operator and the welder, the supplier or the repairer is engaged; the qualification procedure applied shall be justified. This qualification
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