Testing of welded joints in thermoplastics semi-finished products - Part 3: Tensile creep test

This European Standard specifies the dimensions, the method of sampling and the preparation of the test specimens, and the conditions for performing the tensile creep test perpendicular to the weld in order to determine the long-term tensile welding factor.
A tensile creep test may be used in conjunction with other tests (e.g. bend test, tensile test, macrographic examination,...) to assess the performance of welded assemblies, made from thermoplastics materials.
The test is applicable to welded assemblies made from thermoplastics materials filled or unfilled such as tubes and fittings, sheets, plates and profiles, but not reinforced, irrespective of the welding process used.

Prüfen von Schweißverbindungen aus thermoplastischen Kunststoffen - Teil 3: Zeitstand-Zugversuch

Diese Europäische Norm legt Maße, Probenahmeverfahren, Probenvorbereitung sowie Durch¬führungs-bedingungen für einen Zeitstand-Zugversuch rechtwinklig zur Schweißnaht fest, bei dem der Zeitstandzug-Schweißfaktor bestimmt wird.
Ein Zeitstand-Zugversuch kann zusammen mit anderen Prüfungen (z. B. Biegeversuch, Zugversuch, makrographische Untersuchung) angewendet werden, um das Betriebsverhalten von Schweißverbindungen aus thermoplastischen Kunststoffen zu beurteilen.
Der Zeitstand-Zugversuch ist auf Schweißverbindungen aus gefüllten oder ungefüllten, jedoch nicht aus verstärkten thermoplastischen Kunststoffen unabhängig vom angewendeten Schweißverfahren anwendbar, z. B. auf Rohre, Fittings, Bahnen und Platten sowie Profile.

Essais des assemblages soudés sur produits semi-finis en thermoplastiques - Partie 3: Essai de fluage en traction

La présente Norme européenne spécifie les dimensions, la méthode d'échantillonnage et la préparation des éprouvettes, ainsi que les conditions d'exécution de l'essai de fluage en traction perpendiculairement à la soudure, afin de déterminer le coefficient de soudure en traction à long terme.
Un essai de fluage en traction peut être utilisé conjointement avec d'autres essais (par exemple : essai de pliage, essai de traction, examen macrographique, ...) pour évaluer les performances des assemblages soudés en thermoplastiques.
Cet essai est applicable aux assemblages soudés constitués de matières thermoplastiques chargées ou non chargées, telles que tubes et raccords, feuilles, plaques et profilés, mais non renforcées, indépendamment du procédé de soudage utilisé.

Preskus zvarjenih spojev plastomernih polizdelkov - 3. del: Preskus lezenja pri natezni obremenitvi

Standard EN 12814-3 določa dimenzije, metodo vzorčenja, pripravo preskusnih vzorcev in pogoje za izvedbo preskusa lezenja pri natezni obremenitvi, pravokotno na zvar, s katerim se določi dolgoročni natezni faktor zvara. Preskus lezenja pri natezni obremenitvi se lahko uporabi skupaj z drugimi preskusi (npr. preskus upogibanja, natezni preskus, makrografski pregled ...) za oceno zmogljivosti varjenih sestavov iz termoplastičnih materialov. Preskus se uporablja za varjene sestave iz polnjenih ali nepolnjenih termoplastičnih materialov, kot so cevi in spojniki, ponjave, plošče, in profili, ki niso ojačani – ne glede na uporabljeni postopek varjenja.

General Information

Status
Published
Publication Date
25-Feb-2014
Current Stage
9093 - Decision to confirm - Review Enquiry
Completion Date
03-Sep-2019

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Preskus zvarjenih spojev plastomernih polizdelkov - 3. del: Preskus lezenja pri natezni obremenitviPrüfen von Schweißverbindungen aus thermoplastischen Kunststoffen - Teil 3: Zeitstand-ZugversuchEssais des assemblages soudés sur produits semi-finis en thermoplastiques - Partie 3: Essai de fluage en tractionTesting of welded joints in thermoplastics semi-finished products - Part 3: Tensile creep test25.160.40Varjeni spoji in variWelded jointsICS:Ta slovenski standard je istoveten z:EN 12814-3:2014SIST EN 12814-3:2014en,fr,de01-maj-2014SIST EN 12814-3:2014SLOVENSKI

STANDARDSIST EN 12814-3:2000/A1:2005SIST EN 12814-3:20001DGRPHãþD
SIST EN 12814-3:2014
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12814-3
February 2014 ICS 25.160.40 Supersedes EN 12814-3:2000English Version

Testing of welded joints in thermoplastics semi-finished products - Part 3: Tensile creep test

Essais des assemblages soudés sur produits semi-finis en thermoplastiques - Partie 3: Essai de fluage en traction

Prüfen von Schweißverbindungen aus thermoplastischen Kunststoffen - Teil 3: Zeitstand-Zugversuch This European Standard was approved by CEN on 30 November 2013.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,

B-1000 Brussels © 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12814-3:2014 ESIST EN 12814-3:2014

EN 12814-3:2014 (E) 2 Contents

Page Foreword ..............................................................................................................................................................3 Introduction .........................................................................................................................................................4 1 Scope ......................................................................................................................................................5 2 Normative references ............................................................................................................................5 3 Terms and definitions ...........................................................................................................................5 4 Symbols and designations ...................................................................................................................5 5 Principle of the test................................................................................................................................6 6 Sampling procedures ............................................................................................................................7 7 Dimensions of test specimens .............................................................................................................7 8 Cutting and preparation of test specimens ........................................................................................9 9 Mechanical testing .............................................................................................................................. 10 10 Test equipment ................................................................................................................................... 10 11 Determination of the long-term welding factor ................................................................................ 11 12 Test report ........................................................................................................................................... 13 Annex A (informative)

Resistance to slow crack growth ............................................................................. 15 Annex B (informative)

Whole pipe tensile creep rupture test ...................................................................... 18 Annex C (informative)

Minimum creep rupture time of the parent material (ttm) for applicability of the long-term welding factor ............................................................................................................. 21 Annex D (informative)

Testing of socket joints ............................................................................................. 22 Bibliography ..................................................................................................................................................... 25

SIST EN 12814-3:2014

EN 12814-3:2014 (E) 3 Foreword This document (EN 12814-3:2014) has been prepared by Technical Committee CEN/TC 249 “Plastics”, the secretariat of which is held by NBN. 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 August 2014, and conflicting national standards shall be withdrawn at the latest by August 2014. 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. This document supersedes EN 12814-3:2000. The main changes with respect to the previous edition are listed below: a) addition of a NOTE for an alternative test using a whole pipe welded sample (Clause 5) making reference to Annex B (informative), Whole pipe tensile creep rupture test; b) addition of a NOTE for the sampling procedures (Clause 6) in case of socket joints with reference to Annex D (informative), Testing of socket joints. EN 12814, Testing of welded joints of thermoplastics semi-finished products, is divided into the following parts: — Part 1: Bend test; — Part 2: Tensile test; — Part 3: Tensile creep test (the present document); — Part 4: Peel test; — Part 5: Macroscopic examination; — Part 6: Low temperature tensile test; — Part 7: Tensile test with waisted test specimens; — Part 8: Requirements. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 12814-3:2014

EN 12814-3:2014 (E) 4 Introduction The design of welded thermoplastics constructions under static load is based on the long-term creep rupture with behaviour, specifically the resistance to slow crack growth of the thermoplastics material and the welds. For design purposes, the relevant characteristic values for the welded joints are the “long-term tensile welding factors” to which this European Standard provides the test method. The long-term tensile welding factors are normally used in conjunction with the creep rupture curve of the parent material, given for example in EN 1778, when designing welded semi-finished products under static load. The long-term tensile welding factor(s), the crack behaviour and the appearance of the fracture surface provide information on the quality of the weld. NOTE The behaviour of the failure obtained during the tensile creep test can be related to the notch sensitivity of the parent material. An example of a test to provide information about the notch sensitivity of parent material is given in Annex A. SIST EN 12814-3:2014

EN 12814-3:2014 (E) 5 1 Scope This European Standard specifies the dimensions, the method of sampling and the preparation of the test specimens, and the conditions for performing the tensile creep test perpendicular to the weld in order to determine the long-term tensile welding factor. A tensile creep test may be used in conjunction with other tests (e.g. bend test, tensile test, macrographic examination, …) to assess the performance of welded assemblies, made from thermoplastics materials. The test is applicable to welded assemblies made from thermoplastics materials filled or unfilled such as tubes and fittings, sheets, plates and profiles, but not reinforced, irrespective of the welding process used. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 13100-1, Non destructive testing of welded joints of thermoplastics semi-finished products — Part 1: Visual examination EN ISO 899-1, Plastics — Determination of creep behaviour — Part 1: Tensile creep (ISO 899-1) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 test temperature temperature of the medium surrounding the test specimen during the test 3.2 test stress test load divided by the minimum cross sectional area of the test specimen 3.3 creep rupture curve regression curve through the geometric mean values of failure times 3.4 minimum failure time ttm creep rupture time of the parent material to ensure that the test method is applicable 3.5 ductile fracture large scale deformation of material from fracture surfaces 3.6 brittle fracture little or no deformation of material from fracture surfaces 4 Symbols and designations Symbols and designations are given in Table 1. SIST EN 12814-3:2014

EN 12814-3:2014 (E) 6 Table 1 — Symbols and designations Symbols Designations Units a Minimum measured thickness of test specimen within calibrated and parallel length mm an Nominal thickness of test piece mm b Width of calibrated and parallel length of the test specimen mm b1 Width of shoulder of the test specimen mm c Depth of the notch mm Dn Nominal outside diameter of the tube mm fl Long-term tensile welding factor

Fs Value of the force applied to the welded test specimen calculated from the chosen value of 1s N Ft Value of the force applied to the unwelded test specimen calculated from the chosen value of 1t N L Total length of the test specimen mm Lj Minimum distance between the clamping jaws mm L0 Calibrated and parallel length of the test specimen mm Lw a Maximum width of the weld bead of the test specimen mm r Radius of shoulder of the test specimen mm ttm Minimum failure time h 1s Value of stress of the welded test specimens used in the calculation of fl N/mm2 1t Reference stress. Value of stress of the unwelded test specimens, used in the calculation of fl N/mm2 a For extrusion and hot gas welds only.

5 Principle of the test The test involves subjecting a test specimen to a constant load until fracture occurs. The time to fracture is measured and recorded. NOTE An alternative test using a whole pipe welded sample rather that a test specimen cut form the weld is given in Annex B. SIST EN 12814-3:2014

EN 12814-3:2014 (E) 7 The tests are carried out over a range of temperatures and loads, and in a test medium. Only such media shall be used which cause no swelling or degradation of the polymer. Examples of available test media are air, water or solutions of demineralised water with detergents. Care should be taken to ensure that the condition of the test medium does not influence the results of the test. The applicability of the long-term tensile welding factor for design purposes requires a minimum creep rupture time for the parent material (ttm). Before determining the long-term welding factor for the materials mentioned in Annex C, a tensile creep test should be carried out on the parent material at one of the test conditions given in Table C.1. The values of creep rupture time should be at least that quoted in Table C.1. Application standards may prescribe higher values for these rupture times depending upon the semi-finished product and material. 6 Sampling procedures Welded and unwelded test specimens shall be taken from the same test piece. NOTE In the case of socket joints, see Annex D. The test specimens (welded and unwelded) shall be cut perpendicular to the welded joint at least eight hours after welding. For sheets where the extrusion direction is different on either side of the weld, the unwelded test specimens shall be taken from the side of the test piece which has the lowest creep rupture time. Each test specimen shall be marked in order to identify its original position within the test piece. No heat treatment or mechanical straightening operations shall be carried out on the test specimen. 7 Dimensions of test specimens The dimensions of test specimens according to Figure 1 are given in Table 2 and those according to Figure 2 are given in Table 3. Profiles can be tested if test specimens are in accordance with the dimensions given in Table 2 or Table 3. For tubes having nominal outside diameter less than 20 mm, the whole tube shall be tested. In this case, the minimum distance between the clamps shall be 200 mm. SIST EN 12814-3:2014

EN 12814-3:2014 (E) 8
Key Lj
= L0 + (2xb) Figure 1 — Type 1 test specimen for flat and tubular assemblies
Figure 2 — Type 2 test specimen for flat and tubular assemblies
SIST EN 12814-3:2014

EN 12814-3:2014 (E) 9 Table 2 — Dimensions of type 1 test specimens Dimensions in millimetres Dn or an b L0 L 20 ≤ Dn < 50 10nnDa+ 80 ≥ 120 50 ≤ Dn < 100 10nnDa+ 120 ≥ 170 Dn ≥ 100 or flat assemblies:

an ≤ 10 15 120 ≥ 170 10 < an ≤ 20 30 120 ≥ 170 an > 20 1,5 x an 3 x an + Lw with 120 min ≥ L0 + 80

Table 3 — Dimensions of type 2 test specimens Dimensions in millimetres Dn or an b min. b1 L0 L r 20 ≤ Dn < 50 10nnDa+ b + 10 Lw + 60 ≥ 120 60 50 ≤ Dn < 100 10nnDa+ b + 10 Lw + 60 ≥ 170 60 Dn ≥ 100 or flat assemblies:

an ≤ 10 10 20 115 ≥ 170 60 10 < an ≤ 20 30 40 115 ≥ 170 60 an > 20 1,5 x an 2,5 x an 3 x an + Lw with 120 min ≥ L0 + 80 60

Where the beads are left intact in service, they shall be left intact for the test. Where the beads are removed in service, they shall be removed prior to testing. The minimum value for b shall be 6 mm. The tolerance for b shall be ± 1 mm. The tolerance for L0 shall be ± 2 mm. The variation of b over the length L0 shall not exceed ± 2 % of the average value of b. 8 Cutting and preparation of test specimens The tensile creep test specimens shall be cut with parallel sides as shown in Figures 1 and 2. During cutting, heating of the test specimen shall be minimized. The cutting operation shall not cause any damage to the test specimen. After cutting, a visual examination of the weld according to EN 13100-1 shall be carried out and recorded. SIST EN 12814-3:2014

EN 12814-3:2014 (E) 10 9 Mechanical testing The stress is applied to the test specimen at constant temperature, static tensile load and constant am

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