1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-22675-6 SANS 7500-2:2009Edition 1ISO 7500-2:2006Edition 2SOUTH AFRICAN NATIONAL STANDARD Metallic materials Verification of static uniaxia
4、l testing machines Part 2: Tension creep testing machines Verification of the applied force This national standard is the identical implementation of ISO 7500-2:2006 and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr La
5、tegan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 7500-2:2009 Edition 1 ISO 7500-2:2006 Edition 2 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS TC 164,
6、Engineering materials Mechanical testing of metals, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in October 2009. Reference numberISO 7500-2:2006(E)ISO 2006INTERNATIONAL STANDARD ISO7500-2Second ed
7、ition2006-12-15Metallic materials Verification of static uniaxial testing machines Part 2: Tension creep testing machines Verification of the applied force Matriaux mtalliques Vrification des machines pour essais statiques uniaxiaux Partie 2: Machines dessai de fluage en traction Vrification de la f
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13、g Web www.iso.org Published in Switzerland ii ISO 2006 All rights reservedSANS 7500-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 7500-2:2006(E) ISO 2006 All rights reserved iiiContents Page Foreword iv 1 Scope . 1 2 Normative ref
14、erences . 1 3 Symbols and their meanings. 2 4 General inspection of the testing machine 2 5 Verification of the force applied by the testing machine 3 5.1 General. 3 5.2 Masses . 3 5.3 Determination of the discrimination threshold 3 5.4 Determination of the lower limit of verification . 4 5.5 Test p
15、rocedure 4 5.6 Assessment of the force applied by the machine . 6 6 Class of the testing machine . 6 6.1 General. 6 6.2 Lever-type creep testing machines. 6 6.3 Creep testing machines with the force applied by direct acting masses . 7 6.4 Creep testing machines with the force applied directly by a s
16、pring. 7 7 Verification report. 8 8 Intervals between verifications . 8 Annex A (normative) General inspection of the testing machine . 9 SANS 7500-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 7500-2:2006(E) iv ISO 2006 All right
17、s reservedForeword ISO (the International Organization for Standardization) is a 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
18、 which a technical committee has been established has the right to be represented 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 a
19、ll matters of electrotechnical standardization. International Standards are drafted 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
20、 circulated to the member bodies for voting. Publication as an International Standard 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 re
21、sponsible for identifying any or all such patent rights. ISO 7500-2 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee SC 1, Uniaxial testing. This second edition cancels and replaces the first edition (ISO 7500-2:1996), which has been technically revised. ISO
22、 7500 consists of the following parts, under the general title Metallic materials Verification of static uniaxial testing machines: Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system Part 2: Tension creep testing machines Verification of the appli
23、ed force SANS 7500-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD ISO 7500-2:2006(E) ISO 2006 All rights reserved 1Metallic materials Verification of static uniaxial testing machines Part 2: Tension creep testing
24、 machines Verification of the applied force 1 Scope This part of ISO 7500 specifies the verification of testing machines used for uniaxial creep testing in tension in accordance with ISO 204. The verification consists of a general inspection of the testing machine, and a verification of the force ap
25、plied by the testing machine. This part of ISO 7500 applies to dead-weight machines, lever-type creep testing machines and direct-spring-loading machines. Machines with a force-measuring system1)should be verified in accordance with ISO 7500-1, Metallic materials Verification of static uniaxial test
26、ing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system. 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 re
27、ferences, the latest edition of the referenced document (including any amendments) applies. ISO 204, Metallic materials Uniaxial creep testing in tension Method of test ISO 376, Metallic materials Calibration of force-proving instruments used for the verification of uniaxial testing machines 1) For
28、the purposes of this part of ISO 7500, a force-measuring system comprises the load cell plus conditioning plus indicator. SANS 7500-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 7500-2:2006(E) 2 ISO 2006 All rights reserved3 Symbo
29、ls and their meanings For the purposes of this part of ISO 7500, the symbols in Table 1 apply. For the purposes of this part of ISO 7500 the following types of creep testing machines are recognized: dead-weight machines, with or without guides (Figures A.1 and A.2); overslung or underslung lever mac
30、hines (Figures A.3, A.4 and A.5); jockey-weight machines, either with overslung or underslung lever (Figures A.6 and A.7); any combination of the types of machines mentioned above (Figure A.8); testing machines with force applied by a spring (Figure A.9). Table 1 Symbols and meaning Symbol Unit Mean
31、ing FNN Maximum force of the force range of the testing machine FiN Force applied to creep testing machine: for dead-weight machines: Fi= mgna for lever-type machines: Fi= mgnRa for jockey-weight machines, the value of Fiis indicated on the scale of the machine for spring-type machines: force applie
32、d to spring-calibration device F N True force indicated by the force-proving instrument F N Arithmetic mean of several measurements of F or Fiat the same discrete force Fmax, FminN Highest or lowest value of F or Fiat the same discrete force FMN Force applied by the masses on the scale pan of the ma
33、chines FVN Lower limit of the verified force range R Lever ratio used for the verification b % Relative repeatability error of the force-measuring system of the testing machine d N Discrimination threshold d1N Discrimination threshold corresponding to 20 % of the maximum force of the force range (FN
34、) a % Relative discrimination threshold q % Relative accuracy error of the force-measuring system of the testing machine agn= standard acceleration of free fall, in m/s2(gn= 9,806 65 m/s2). This quantity was earlier also called “standard acceleration due to gravity”. 4 General inspection of the test
35、ing machine The verification of the testing machine shall only be carried out if the machine is in good working order. For this purpose, a general inspection of the machine shall be carried out before verification of the force applied by the machine (see Annex A). SANS 7500-2:2009This s tandard may
36、only be used and printed by approved subscription and freemailing clients of the SABS .ISO 7500-2:2006(E) ISO 2006 All rights reserved 35 Verification of the force applied by the testing machine 5.1 General This verification shall be carried out for each of the force ranges used. If the testing mach
37、ine has several force ranges, each force range2)shall be regarded as a separate testing machine. This verification shall be carried out using tension-force-proving instruments. These instruments shall be in accordance with ISO 376. The class of the force-proving instrument shall be equal or superior
38、 to the class determined for the creep testing machine. 5.2 Masses The masses used to apply the forces during the verification can be either a) known masses with an accuracy equal to or better than 0,1 %, verified at least every five years, or b) masses dedicated for use with a given creep testing m
39、achine, applied in the same sequence as during the test. 5.3 Determination of the discrimination threshold The discrimination threshold (d) of the machine is defined as the smallest increment of force that can be applied and detected during the verification procedure. The discrimination threshold (d
40、) shall be determined at 20 %, 60 % and 100 % of the maximum force FNof the force range. If forces of a magnitude less than 0,2 FNare to be tested (see 5.2), the discrimination threshold shall additionally be determined at the lower limit of the provided testing range. The discrimination threshold (
41、d) is measured at the magnitude of the force resulting from the smallest mass added to, or removed from, the scale pan of the machine, or the force which corresponds to the smallest recordable movement of the jockey weight which causes a detectable change at the indicator of the force-proving instru
42、ment. The relative discrimination threshold (a) is calculated for each level of force specified according to the following formula : 100daF= (1) and shall remain within the limits given in Table 3 for the class of machine considered. The discrimination threshold (d) shall be expressed in newtons. 2)
43、 Force range means, in the case of a deadweight machine, the range over which the machine is to be used; in the case of a lever-type machine it is the force range for each separate lever ratio. SANS 7500-2:2009This s tandard may only be used and printed by approved subscription and freemailing clien
44、ts of the SABS .ISO 7500-2:2006(E) 4 ISO 2006 All rights reserved5.4 Determination of the lower limit of verification The lower limit of verification (FV) shall be specified according to Table 2. Table 2 Lower limit of verification Class FV0,5 400 d11 200 d12 100 d1d1is the discrimination threshold
45、corresponding to 20 % of the force-measuring range. NOTE The lower limit of verification of the machine may be less than the permissible operating range of the equivalent-grade force-proving instrument used to determine the discrimination threshold at the 60 % and maximum force conditions. Consequen
46、tly, to verify the testing machine precisely at the lower end of the range, it will be necessary to use two measuring instruments, one for the upper range and a second one having appropriate capacity for the extreme lower measuring range. 5.5 Test procedure 5.5.1 General Verification shall be carrie
47、d out for each force range for which a grade is sought. Verification shall not be performed below the lower limit FVfor any force range. 5.5.2 Alignment The force-proving device shall be mounted in the machine, with the self-alignment devices normally used included at each end of the loading train.
48、5.5.3 Balancing the lever 5.5.3.1 General It is necessary to balance the loading train to achieve a zero loading reading on the force-proving device when it is mounted in the loading train in place of the test piece. The precise method of balancing is dependent upon the design of the machine; howeve
49、r, in general the procedures described in 5.5.3.2 and 5.5.3.3 will be applicable. 5.5.3.2 Overslung lever The force-verification device shall be hung in the loading train in place of the test specimen, with the lower loading bar disconnected immediately below the proving device. The lever shall then be balanced by movement of the adjustment weight normally attached to the machine, or by the addition of an extra balancing weight. The force indicator of the verification device
