1、DEUTSCHE NORM Julv 1999 Metallic materials Tube ring hydraulic pressure test English version of DIN EN 10275 I DIN - EN 10275 ICs 77.040.10 Metallische Werkstoffe - Hydraulischer Ringaufweitversuch European Standard EN 10275 : 1999 has the status of a DIN Standard. A comma is used as the decimal mar
2、ker. National foreword This standard has been prepared by ECISS/TC 29. The responsible German body involved in its preparation was the Normenausschu Materialprfung (Materials Testing Standards Committee), Technical Committee Rohrprfung. EN comprises 11 pages. No pari of this standard may be reproduc
3、ed without the prior permission of V Deutsches Institut fur Normung e. V., Berlin. Luth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). Ref. No. DIN EN 10275 : 1999-0 English price group 08 Sales No. 1108 o1 .o0 EUROPEAN STANDARD NORME EUROPENNE EUROPI
4、SCHE NORM EN 10275 May 1999 ICs 77.040.1 O English version Metallic materials Tube ring hydraulic pressure test Matriaux mtalliques - Essai dexpansion hydraulique sur anneau tubulaire Metallische Werkstoffe - Hydraulischer Ringaufweitversuch This European Standard was approved by CEN on 1999-04-1 6.
5、 CEN members are bound to comply with the CENKENELEC 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 stand- ards may be obtained on
6、 application to the Central Secretariat or to any CEN member. The European Standards exist 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 Central Secretariat
7、has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom.
8、CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1999. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN 10275 : 199
9、9 E Page 2 EN 10275 : 1999 Contents Foreword 1 Scope 2 Symbols 3 Principle 4 Apparatus 5 Test ring 6 Test procedure 7 Hoop strength evaluation 8 Test report Annex A (informative) Proof and reduced section testing Page 2 3 3 3 5 5 7 10 10 11 Foreword This European Standard has been prepared by Techni
10、cal Committee ECISS/TC 29 “Steel tubes and fittings for steel tubes”, the secretariat of which is held by UNI. 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 November 1999, and conflicting nation
11、al standards shall be withdrawn at the latest by November 1999. This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. This European Standard is considered to be a supporting standard to those application and product
12、standards which in themselves support an essential safety requirement of a New Approach Directive and which make reference to this European Standard. According to the CENKENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European
13、 Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Page 3 EN 10275 : 1999 1 Scope This European Standard specifies the ring hydraulic pressure t
14、est for metallic tubes. It is generally applied to tubes with an outside diameter generally greater than 120 m and outside diameter to thickness ratio not less than 20. The objective of this test is to ascertain the value of the hoop stress required to produce a specified total circumferential (hoop
15、) strain. 2 Symbols Symbols and corresponding designations are given in table 1. Table 1: Symbols and designations Symbol T D L P R, X Unit mm mm N/mm2 N/mm2 m Desi gnation Measured tube test ring thickness Measured outside diameter of the tube test ring Length of tube test ring Hydrostatic pressure
16、 to produce the specified total strain Specified total strain Hoop strength at the specified total strain 3 Principle The test involves the unrestrained expansion of the test ring between two platens. under internal hydraulic pressure; the outer circumference of the tube is the effective test piece
17、gauge length. The test is cnrried out on a test piece (see figure 1) removed from a welded or seamless tube of thickness up to a limit dependent upon the capacity of the machine and the strength of the tube. Where the hydraulic pressure required to produce the specified circumferential strain exceed
18、s the capacity of the test machine modified tests may be carried out as describcd in annex A. The test is specified when a measure of the hoop strength is required which is not influcnccd by cold forming and residual stress introduced when flattening a standard tensile test piece. The standard tensi
19、le test is necessary however, when tensile strength and elongation measurements are required. Page 4 EN 10275 : 1999 Both faces to be machined parallel with fine turned or ground finish I Maximum deviation from normal O, 15 mm ) Tolerance on L f 0,2S mm L is commonly taken as 76 mm. NOTE: Remove ali
20、 sharp edges and protect machined surfaces. Figure 1:. Test ring dimensions and tolerances Page 5 EN 10275 : 1999 4 Apparatus 4.1 The testing machine shall be capable of allowing the test ring to expand freely without imposing any end restraint. This shall be achieved by leaving a small gap between
21、the test piece and the top platen. Pressure loss during testing shall be prevented by the use of a flexible seal. NOTE: A typical testing machine is shown schematically in figure 2. 4.2 To reduce friction between the test piece, platens and inner die to a minimum, the platens shall be parallel and h
22、ave a fine turned or ground finish. Prior to each test, friction at the contact surfaces shall be further minimized either by the use of a lubricant e.g. graphited grease or by the use of PTFE (polytetrafluorethylene) sheet. The platens shall be inspected regularly and any ridges that develop shall
23、be removed. 4.3 Stress shall be applied to the test ring by means of a pressurized fluid. Provision shall be made to remove any air in the system through a bleed line. 5 Test ring 5.1 Shape and position 5.1.1 Prior to separation from the main body of the tube the test ring shall be marked with a uni
24、que identification. 5.1.2 The test ring may be prepared from an oversize flame cut sample. Final preparation shall be by a cold machining process to ensure removal of any heat affected zones. The machined edges shall have a fine turned or ground finish and be free from burrs. 5.1.3 The dimensions an
25、d tolerances for the test piece are given in figure 1. The machined edges shall be parallel and normal to the axis of the tube to within 0.15 mm measured across the diameter. 5.2 Determination of dimensions 5.2.1 The outside diameter of the test ring shall be calculated from measurement of the tube
26、circumference, e.g. using a flexible steel tape. The maximum tolerance on the accuracy of this measurement shall be * 1 mm. Page 6 EN 10275 : 1999 Y v1 o, c1 2 % .I f pa E .C( Y v1 o, CI cr O E 5 Q i ED cp O .I Y E o, c u u3 N o, i 5 M iz Page 7 EN 10275 : 1999 5.2.2 The wall thickness shall be dete
27、rmined by calculating the mean of eight measurements taken at approximately 45 O intervals around the test piece, excluding the weld region of welded tubes (see figure 3). The measuring device shall be capable of measuring thickness with an accuracy of better than 0,025 mm. 5.2.3 All tube diameter a
28、nd thickness measurements of the test ring shall be fully documented. 6 Test procedure 6.1 The test procedure consists of applying pressure and measuring circumferential extension. 6.2 Circumferential extension of the test ring shall be measured during pressurization as follows. The equipment for me
29、asuring the change of circumference, e.g. steel tape or roller chain extensometer shall be wrapped around the test ring perimeter at the mid-point and crossing at the weld. NOTE: An example of the use of a steel tape is shown in figure 4. When a steel tape is used friction shall be minimized by coat
30、ing both the tape and test ring circumference with a suitable lubricant. Change in circumference shall be measured by a suitable mechanical or electrical device having an accuracy of I 0,25 mm. 6.3 The equipment for measuring the increase in circumference shall be wrapped around the test ring before
31、 application of the internal pressure. 6.4 The tolerance for the measurement of internal pressure shall be within i 1 %. Accuracy of the pressure measurement device shall be verified, e.g. by comparison with dead weight test equipment, at the commencement of a sequence of testing and then once every
32、 200 tests, and not less than once per year during the testing period. 6.5 The rate of strain shall not exceed 0,2 5% per minute. 6.6 The pressure and circumferential extension output signals shall be recorded, for example on a X-Y plotter, and related to the test piece identity. Page 8 EN 10275 : 1
33、999 8 (Adjacent to the weld) I Figure 3: Wall thickness measurement positions Page 9 EN 10275 : 1999 Test ring Measuring device (e.g. steel tape) NOTE: The separation between the two parallel portions of the measunng device shall he between 1,5 nim and 3.0 IIIITI. Figure 4:. Measuring device positio
34、n for extension measurement Page 1 O EN 10275 : 1999 7 Hoop strength evaluation 7.1 A typical test pressure-circumferential extension record is shown in figure 5. 7.2 The pressure p corresponding to the specified total strain shall be determined from the test record. 7.3 For tubes where DIT 2 20 the
35、 hoop strength at the specified total strain shall be calculated from the formula: NOTE 1 : For tubes with D/T c 20 the hoop strength calculated from this formula becomes increasingly inaccurate and quantitative results should be used with caution. Factors such as strain hardening could have a signi
36、ficant effect on the validity of the calculated strength. NOTE 2: The specified total strain is calculated from the circumferential extension divided by the original test ring circumference. 8 Test report Thc tcst report shall contain at least the following information: a) reference to this European
37、 standard i.e. EN 10275; b) identification of test ring, e.g. cast no/tube noidentification no; c) material specification, if known; d) diameter and wall thickness of the tube; e) length of the tube test ring; f) calculated hoop strength at specified total strain; g) reference to an alternative test
38、 method used, when appropriate (see annex A). Page 11 EN 10275 : 1999 Specified total extension Pressure at / specified extension Circumferential extension Figure 5:. Typical pressurelextension test record Annex A (informative) Proof and reduced section testing A.l Proof testing This method may be u
39、sed where the stress necessary to produce the specified circumferential extension has not been achieved but where the stress in the test ring exceeds the specified minimum hoop strength requirement. In this case the percentage circumferential expansion achieved shall be quoted in the report. A.2 Red
40、uced section testing This method enables the stress corresponding to the specified circumferential extension to be achieved by a reduction in the test ring thickness. This reduction can be effected by machining the inside andor outside diameter. To ensure that the full thickness is represented two or possibly three tests should be carried out after machining i) inside, ii) outside and iii) both diameters. Details of all test piece locations and dimensions relative to the full thickness ring section will be included in the report.
