1、BS EN ISO12004-2:2008ICS 77.040.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDMetallic materials Sheet and strip Determination offorming-limit curvesPart 2: Determination of forming-limit curves in the laboratory (ISO12004-2:2008)This British Standardwas pub
2、lished underthe authority of theStandards Policy andStrategy Committee on 30November 2008 BSI 2008ISBN 978 0 580 57022 3Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 12004-2:2008National forewordThis British Standard is the UK implementation of EN ISO12004-2:2008.The UK partic
3、ipation in its preparation was entrusted to TechnicalCommittee ISE/NFE/4/2, Ductility testing.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible
4、 for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 12004-2October 2008ICS 77.040.10English VersionMetallic materials - Sheet and strip - Determination of forming-limit curves - Part 2: Det
5、ermination of forming-limit curves in thelaboratory (ISO 12004-2:2008)Matriaux mtalliques - Tles et bandes - Dterminationdes courbes limites de formage - Partie 2: Dterminationdes courbes limites de formage en laboratoire (ISO 12004-2:2008)Metallische Werkstoffe - Bleche und Bnder - Bestimmungder Gr
6、enzformnderungskurve - Teil 2: Bestimmung vonGrenzformnderungskurven im Labor (ISO 12004-2:2008)This European Standard was approved by CEN on 12 October 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the
7、status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German).
8、 A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic
9、, 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.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALI
10、SATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 12004-2:2008: EBS EN ISO 12004-2:2008EN ISO 12004-2:2008 (E) 3 Foreword This document
11、 (EN ISO 12004-2:2008) has been prepared by Technical Committee ISO/TC 164 “Mechanical testing of metals“ in collaboration with Technical Committee ECISS/TC 1 “Steel - Mechanical testing” the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standa
12、rd, either by publication of an identical text or by endorsement, at the latest by April 2009, and conflicting national standards shall be withdrawn at the latest by April 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN
13、and/or CENELEC shall not be held responsible for identifying any or all such patent rights. 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, Cyprus, Czech Repu
14、blic, 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. Endorsement notice The text of ISO 12004-2:2008 has
15、 been approved by CEN as a EN ISO 12004-2:2008 without any modification. BS EN ISO 12004-2:2008ISO 12004-2:2008(E) ISO 2008 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Symbols and abbreviated terms . 1 3 Principle. 2 4 Test pieces and equipment 3 5 Analysis of strai
16、n profile and measurement of 1- 2pairs . 10 6 Documentation 15 7 Test report . 16 Annex A (normative) Second derivative and “filtered” second derivative 17 Annex B (normative) Calculation of the width of the fit window. 18 Annex C (normative) Evaluation of the inverse best-fit parabola on the “bell-
17、shaped curve” 19 Annex D (normative) Application/Measurement of grid Evaluation with magnifying glass or microscope 21 Annex E (informative) Tables of experimental data for validation of calculation programme. 22 Annex F (normative) Representation and mathematical description of FLC. 23 Annex G (inf
18、ormative) Examples of critical cross-sectional data . 24 Annex H (normative) Flowchart from measured strain distributions to FLC values 25 Bibliography . 27 BS EN ISO 12004-2:2008ISO 12004-2:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a
19、 worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represente
20、d on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are draf
21、ted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Sta
22、ndard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 12004-2 was prepare
23、d by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee SC 2, Ductility testing. This first edition of ISO 12004-2, together with ISO 12004-1, cancels and replaces ISO 12004:1997 which has been technically revised. ISO 12004 consists of the following parts, under the general
24、title Metallic materials Sheet and strip Determination of forming-limit curves: Part 1: Measurement and application of forming-limit diagrams in the press shop Part 2: Determination of forming-limit curves in the laboratory BS EN ISO 12004-2:2008ISO 12004-2:2008(E) ISO 2008 All rights reserved vIntr
25、oduction A forming-limit diagram (FLD) is a diagram containing major/minor strain points. An FLD can distinguish between safe points and necked or failed points. The transition from safe to failed points is defined by the forming-limit curve (FLC). To determine the forming limit of materials, two di
26、fferent methods are possible. 1) Strain analysis on failed press shop components to determine component and process dependent FLCs: In the press shop, the strain paths followed to reach these points are generally not known. Such an FLC depends on the material, the component and the chosen forming co
27、nditions. This method is described in ISO 12004-1. 2) Determination of FLCs under well-defined laboratory conditions: For evaluating formability, one unique FLC for each material in several strain states is necessary. The determination of the FLC has to be specific and it is necessary to use differe
28、nt linear strain paths. This method should be used for material characterization as described in ISO 12004-2. For this part of ISO 12004 (concerning determination of forming-limit curves in laboratory), the following conditions are also valid. Forming-limit curves (FLCs) are determined for specific
29、materials to define the extent to which they can be deformed by drawing, stretching or any combination of drawing and stretching. This capability is limited by the occurrence of fracture, localized necking. Many methods exist to determine the forming limit of a material; however, it should be noted
30、that results obtained using different methods cannot be used for comparison purposes. The FLC characterizes the deformation limit of a material in the condition after a defined thermo-mechanical treatment and in the analysed thickness. For a judgement of formability, the additional knowledge of mech
31、anical properties and the materials history prior to the FLC-test are important. To compare the formability of different materials, it is important not only to judge the FLC but also the following parameters: a) mechanical properties at least in the main direction; b) percentage plastic extension at
32、 maximum force, according to ISO 6892-1; c) r-value with given deformation range, according to ISO 10113; d) n-value with given deformation range, according to ISO 10275. BS EN ISO 12004-2:2008BS EN ISO 12004-2:2008INTERNATIONAL STANDARD ISO 12004-2:2008(E) ISO 2008 All rights reserved 1Metallic mat
33、erials Sheet and strip Determination of forming-limit curves Part 2: Determination of forming-limit curves in the laboratory 1 Scope This part of ISO 12004 specifies the testing conditions to be used when constructing a forming-limit curve (FLC) at ambient temperature and using linear strain paths.
34、The material considered is flat, metallic and of thickness between 0,3 mm and 4 mm. NOTE The limitation in thickness of up to 4 mm is proposed, giving a maximum allowable thickness to the punch diameter ratio. For steel sheet, a maximum thickness of 2,5 mm is recommended. 2 Symbols and abbreviated t
35、erms For the purposes of this document, the symbols and terms given in Table 1 apply. Table 1 Symbols and abbreviated terms Symbol English French German Unite Engineering strain Dformation conventionnelle Technische Dehnung % True strain (logarithmic strain) Dformation vraie (dformation logarithmiqu
36、e) Wahre Dehnung (Umformgrad, Formnderung) 1Major true strain Dformation majeure vraie Grssere Formnderung 2Minor true strain Dformation mineure vraie Kleinere Formnderung 3True thickness strain Dformation vraie en paisseur Dickenformnderung Standard deviation Ecart-type Standardabweichung D Punch d
37、iameter Diamtre du poinon Stempeldurchmesser mmDbhCarrier blank hole diameter Diamtre du trou du contre-flan Lochdurchmesser des Trgerblechs mm X(0), X(1) X(m) X(n) X-position Position en X X-Position mm f(x) = ax2+ bx + c Best-fit parabola Parabole de meilleur fit Best-Fit-Parabel f(x) = 1/(ax2+ bx
38、 + c) Best-fit inverse parabola Parabole inverse de meilleur fit Inverse Best-Fit-Parabel BS EN ISO 12004-2:2008ISO 12004-2:2008(E) 2 ISO 2008 All rights reservedTable 1 (continued) Symbol English French German UnitS(0), S(1).S(5) Section Section Schnitt n Number of X-positions Nombre de points en X
39、 Nummer der X-Positionen m Section number of the failure position Numro de la section correspondant la rupture Nummer des Schnittes zum Riss w Width of the fit window Largeur de la fentre de fit Breite des Fit-Fensters mm t0Initial sheet thickness paisseur initiale de la tle Ausgangsblechdicke mmr P
40、lastic strain ratio Coefficient danisotropie plastique Senkrechte Anisotropie Table 2 gives a comparison of the symbols used in different countries. Table 2 Comparison of symbols used in different countries English French German Germansymbol Anglo-American symbol Format Unit Engineering strain Dform
41、ation conventionelle Technische Dehnung e % True strain (logarithmic strain) Dformation vraie (Dformation logarithmique) Wahre Dehnung (Umformgrad, Formnderung) Decimal = ln(1 + e) = ln(1 + e) = ln(1 + ) The symbol used for true strain in Anglo-American-speaking countries is “ ”; in German-speaking
42、countries, the symbol “” is used for true strain. In German-speaking countries, the symbol “ ” is used to define engineering strains. The notation for true strain used in this text is “ ” following the Anglo-American definition. 3 Principle The FLC is intended to represent the almost intrinsic limit
43、 of a material in deformation assuming a proportional strain path. To determine the FLC accurately, it is necessary to have a nearly frictionless state in the zone of evaluation. A deterministic grid of precise dimensions or a stochastic pattern is applied to the flat and undeformed surface of a bla
44、nk. This blank is then deformed using either the Nakajima or the Marciniak procedure until failure, at which point the test is stopped. The measurement should be performed using a “position-dependent” method (see 5.2). NOTE A “time-dependent” method is under development. The deformation (strain) acr
45、oss the deformed test piece is determined and the measured strains are processed in such way that the necked or failed area is eliminated from the results. The maximum strain that can be imposed on the material without failing is then determined through interpolation. This maximum of the interpolate
46、d curve is defined as the forming limit. BS EN ISO 12004-2:2008ISO 12004-2:2008(E) ISO 2008 All rights reserved 3The forming limits are determined for several strain paths (different ratios between 1and 2). The determined strain paths range from uniaxial tension to biaxial tension (stretch drawing).
47、 The collection of the individual forming limits in different strain states is plotted as the forming-limit curve. The curve is expressed as a function of the two true strains 1and 2on the sheet surface and plotted in a diagram, the forming-limit diagram. The minor true strains 2are plotted on the X
48、-axis and the major principal true strains 1on the Y-axis (see Figure 1). Standard conversion formulae permit the calculation of major (1) and minor true strains (2). In the following, the word strain implies the true strain, which is also called logarithmic strain. Key X minor true strain, 2Y major
49、 true strain, 1F FLC 1 uniaxial tension, 2= r/(r + 1)12 intermediate tensile strain 3 plane strain 4 intermediate stretching strain state 5 intermediate stretching strain state 6 equi-biaxial tension (= stretching strain state) 2= 1Figure 1 Illustration of six different strain paths 4 Test pieces and equipment 4.1 Test pieces 4.1.1 Thickness of test pieces This procedure is intended for flat, metallic sheets with thickness
