1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 4268:2012Aerospace series Metallic materials Heat treatment facilities General requirementsBS EN 4268:2012 BRITISH STANDARDNational forewordThis British Standard is the UK
2、implementation of EN 4268:2012. The UK participation in its preparation was entrusted to TechnicalCommittee ACE/61, Metallic materials for aerospace purposes. A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to includ
3、e all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012.ISBN 978 0 580 75192 9 ICS 25.200; 49.025.05; 49.025.15 Compliance with a British Standard cannot confer immunity from lega
4、l obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS EN 4268:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 4268 October 2012 ICS 25.200; 49.
5、025.05; 49.025.15 English Version Aerospace series - Metallic materials - Heat treatment facilities -General requirements Srie arospatiale - Matriaux mtalliques - Installations de traitement thermique - Exigences gnrales Luft- und Raumfahrt - Metallische Werkstoffe - Wrmebehandlungsanlagen - Allgeme
6、ine Anforderungen This European Standard was approved by CEN on 15 July 2011. 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 bibl
7、iographical 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 respon
8、sibility 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 Repu
9、blic 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 COMIT EUROPEN DE NORMA
10、LISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 4268:2012: EBS EN 4268:2012EN 4268:2012 (E) 2 Contents Page Foreword 31 Scope 42 Norm
11、ative references 43 General 44 Terms and definitions .45 Heat treatment facility requirements .65.1 General 65.2 Category classification .65.3 Heating media 65.4 Quenching equipment and quenchants 65.5 Temperature sensors 75.5.1 General 75.5.2 Temperature sensor accuracy (M) .75.5.3 Number and distr
12、ibution of recording sensors 75.6 Designation 85.7 Temperature setting (W) and indicating accuracy (A) .85.8 Accuracy of recorder (R), grade of accuracy (RK), resolution of recording (RA) and rate of paper feed (PV) .96 Tests . 106.1 General . 106.2 Test instruments . 116.3 Test frequency 116.4 Exte
13、nt of testing 116.5 Test procedures 116.5.1 Accuracy test (V) and test frequency (TV) . 116.5.2 Temperature uniformity test and test frequency (TT) . 126.5.3 Instrument test (PG) and instrument test frequency (TPG) . 137 Test results and documentation . 147.1 Evaluation of temperature measurement .
14、147.2 Evaluation of temperature uniformity . 147.3 Documentation of test results . 14BS EN 4268:2012EN 4268:2012 (E) 3 Foreword This document (EN 4268:2012) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). After enquiries and votes carried
15、 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. This European Standard shall be given the status of a national standard, either by p
16、ublication of an identical text or by endorsement, at the latest by April 2013, and conflicting national standards shall be withdrawn at the latest by April 2013. 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
17、shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic,
18、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. BS EN 4268
19、:2012EN 4268:2012 (E) 4 1 Scope This European Standard covers the general requirements for heat treatment facilities processing semi-finished products and parts in metallic aerospace materials. It defines the terms used herein and describes the test procedures and requirements for mandatory tests of
20、 heat treatment facilities. It also serves as an aid in the surveillance and approval of heat treatment facilities. This standard applies to all types of heat treatment facilities, including those using direct or indirect heat transfer and liquid or gaseous heating media, with our without circulatio
21、n, and to vacuum furnaces. 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 do
22、cument (including any amendments) applies. IEC 60584-2, Thermocouples Part 2: Tolerances 1)3 General The heat treatment of metallic materials produces specific material properties only if performed within relatively narrow temperature ranges, the respective tolerances of which are specified in the a
23、pplicable standards. A heat treatment facility can therefore be used for a heat-treating operation only provided its temperature variations over space and time remain within the specified temperature tolerance. Proper temperature distribution in the heat treatment facility depends on e.g. the type o
24、f furnace or bath, the heating medium, the control instruments with their feedback and run-up circuitry, and the rigging and positioning of control sensors. A suitable recording instrument is needed to properly monitor and document the heat treatment. 4 Terms and definitions For the purposes of this
25、 document, the following terms and definitions apply. 4.1 temperature uniformity measure of the temperature variation at various points in the effective working volume after thermal equilibrium has been reached 4.2 effective working volume for the purposes of the present standard, the effective work
26、ing volume is the working zone of the heat treatment facility in which temperatures run within the specified maximum temperature variation and which is available for the intended heat treatment 1) Published by International Commission Electrotechnique Internationale http:/www.iec.ch/ (CENELEC EN 605
27、84-2). BS EN 4268:2012EN 4268:2012 (E) 5 4.3 maximum temperature variation maximum temperature variation indicates how much the temperatures at different points in the effective working volume are allowed to vary from the working temperature after thermal equilibrium has been reached 4.4 category cl
28、assification depending on their technical characteristics, heat treatment furnaces or baths are classified into 4 categories A, B, C, D of different maximum temperature variation (see Table 1) 4.5 thermal equilibrium thermal equilibrium is reached when following the temperature rise phase no validly
29、 recorded temperature varies by more than 20 % of the maximum allowable temperature variation in the effective working volume for the duration of one closed-loop oscillation 4.6 temperature setting feature permitting analog or digital reproducible selection of the facility temperature set-point 4.7
30、correction factor this is the correction applied to the set-point to achieve the specified working temperature 4.8 working temperature temperature to which the heat treatment facility is brought for a certain heat treatment 4.9 working temperature range range extending from the lowest to the highest
31、 working temperature at which the heat treatment facility is to be operated Note 1 to entry: A code number identifies the maximum allowable working temperature. 4.10 test temperature agreed temperature at which the reference measurement is to be made or the temperature uniformity to be demonstrated
32、4.11 temperature sensors temperature-sensing elements for the various measuring, control and recording functions 4.12 recording sensor temperature-sensing element of a chain of validly indicating and recording instruments 4.13 approval for the purposes of the present standard, approval is the formal
33、 release of a facility for production heat treatment Note 1 to entry: It is granted if compliance with the requirements of the present standard has been demonstrated by acceptance testing. BS EN 4268:2012EN 4268:2012 (E) 6 5 Heat treatment facility requirements 5.1 General Heat treatment facilities
34、shall be capable of satisfying the requirements of the heat treatment process to be applied. Heat treatment facilities as defined in Clause 1 shall be approved prior to their release for production heat treatment and shall be subjected to periodic in-service checks. Approval and periodic checks shal
35、l be performed by the responsible company quality assurance, facilities support and calibration activities. Approval and periodic checks shall be in conformance with the requirements of Clause 6. In the case of safety tests, the competent specialist department shall be consulted. The test results sh
36、all be reported by the competent specialist department and filed with the heat treatment facility records. 5.2 Category classification A heat treatment facility may fall within several categories if designed to operate in different working temperature ranges. Table 1 Maximum permissible temperature
37、variation of effective working volume Code number Working temperature range Maximum permissible temperature variation C CCategoryA B C D 03 300 7,5 5 3 07 300 1 h: PV 10 mm/h R 1,5 C RK = 0,3 RA 3 C/mm for WBD 1 h: PV 30 mm/h for WBD 1 h: PV 20 mm/h R 1 C RK = 0,2 RA 2 C/mm for WBD 2 h: PV 40 mm/h f
38、or WBD 2 h: PV 20 mm/h 07 300 1 h: PV 10 mm/h R 2 C RK = 0,3 RA 4 C/mm for WBD 1 h: PV 30 mm/h for WBD 1 h:PV 20 mm/h R 1,5 C RK = 0,2 RA 3 C/mm for WBD 2 h: PV 40 mm/h for WBD 2 h: PV 20 mm/h 10 700 1 h:PV 10 mm/h R 3 C RK = 0,3 RA 6 C/mm for WBD 1 h: PV 30 mm/h for WBD 1 h:PV 20 mm/h R 2 C RK = 0,
39、2 RA 4 C/mm for WBD 2 h: PV 40 mm/h for WBD 2 h: PV 20 mm/h R 2 C RK = 0,1 RA 4 C/mm for WBD 2 h: PV 40 mm/h for WBD 2 h:PV 20 mm/h 13 1 000 1 h:PV 10 mm/h R 4 C RK = 0,3 RA 8 C/mm for WBD 1 h: PV 30 mm/h for WBD 1 h:PV 20 mm/h R 3 C RK = 0,2 RA 6 C/mm for WBD 2 h: PV 40 mm/h for WBD 2 h: PV 20 mm/h
40、 R 3 C RK = 0,1 RA 6 C/mm for WBD 2 h: PV 40 mm/h for WBD 2 h:PV 20 mm/h 6 Tests 6.1 General The heat treatment facility shall be so designed as to permit performance of the specified tests (e.g. additional lead-ins for temperature sensors, ready accessibility of equipment, concurrent readouts from
41、facility instrumentation and independent test instrumentation). Testing shall invariably be performed using independent test instruments. BS EN 4268:2012EN 4268:2012 (E) 11 6.2 Test instruments The accuracy of test instruments shall be at least equivalent to or better than that of the facility worki
42、ng instruments. Test instrument deviations shall be known. Test instruments shall likewise be subjected to periodic checks. The working instruments are calibrated against the test instruments, which are themselves calibrated against chains of standard instruments traceable to standards maintained by
43、 internationally recognised standards organisations, responsible for establishing National Standards. Test instruments shall be checked at a frequency of every 3 months, 6 months or 12 months or as specified by the manufacturer. In the case of temperature sensors (thermocouples), the frequency also
44、depends on the thermocouple wire diameter, service time, temperature level and heating medium. 6.3 Test frequency The time interval between tests is governed by so-called “dynamic test frequencies”, where k = reduced frequency; n = normal frequency; l = extended frequency. The first test following a
45、cceptance, repair, alteration or relocation of the facility shall be made at frequency “k”, tests thereafter at frequency “n”. If no anomalies are found in three consecutive tests, the frequency requirement may be changed to “l”. When irregularities or deviations are found in operation or use, the f
46、requency shall again revert to “k”. 6.4 Extent of testing Tests are classified into: a) Category I accuracy test; b) Category II temperature uniformity test; c) Category III instrument test. Testing required for acceptance or subsequent to relocation: d) Categories I, II, III. Testing required upon
47、alteration or repair, depending on the type and extent of the rework: e) Categories I, II and/or III. 6.5 Test procedures 6.5.1 Accuracy test (V) and test frequency (TV) Accuracy testing involves checking a heat treatment facilitys chain of validly indicating and recording temperature instruments ag
48、ainst a reference chain installed for calibration purposes. The reference sensor shall be located as close as possible to the facilitys recording sensor. BS EN 4268:2012EN 4268:2012 (E) 12 The permissible temperature variations and the test frequencies are shown in Table 6. Table 6 Maximum permissib
49、le temperature variation in accuracy test (V) and test frequency (TV) Code number Working temperature range Category C A B C D 03 300 V = 4 C TV: k = 1 month n = 2 months l = 4 months V = 3 C TV: k = 1/2 month n = 1 month l = 2 months V = 2 C TV: k = 1 week n = 2 weeks l = 4 weeks 07 300 700 V = 5 C TV: as cod
