SANS 9177-3-2009 Mechanical pencils Part 3 Black leads - Bending strengths of HB leads《制图自动铅笔 第2部分：石墨 HB铅笔芯弯曲强度》.pdf

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 978-0-626-23002-9 SANS 9177-3:2009Edition 1ISO 9177-3:1994Edition 1SOUTH AFRICAN NATIONAL STANDARD Mechanical pencils Part 3: Black leads Bending st

4、rengths of HB leads This national standard is the identical implementation of ISO 9177-3:1994 and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X 191 Pretoria 0001Tel: +27 12 428 791

5、1 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 9177-3:2009 Edition 1 ISO 9177-3:1994 Edition 1 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS TC 1007, Stationery and office requisites, in accordance with procedures of the

6、 SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in October 2009. INT-ERNATIONAL STANDARD IS0 9177-3 First edition 1994-07-01 Mechanical pencils - Part 3: Black leads - Bending strengths of HB leads Porte-mine - Partie 3: Mines graphite

7、- RBsistance A la flexion des mines HB Reference number IS0 9177-3: 1994(E) SANS 9177-3:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .IS0 9177-3:1994(E) Foreword IS0 (the International Organization for Standardization) is a worldwide fe

8、deration of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that com

9、mittee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization, Draft International Standards adopted by the

10、technical committees are 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. International Standard IS0 9177-3 was prepared by Technical Committee ISO/TC 10, Technical drawings, product definitio

11、n and related documen- tation, Subcommittee SC 9, Media and equipment for drawing and related documentation. IS0 9177 consists of the following parts, under the general title Mechan- ical pencils: - Part 1: Classification, dimensions, performance requirements and testing - Part 2: Black leads - Clas

12、sification and dimensions - Part 3: Black leads - Bending strengths of HB leads 0 IS0 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without p

13、ermission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland II SANS 9177-3:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL

14、STANDARD 0 IS0 IS0 9177=3:1994(E) Mechanical pencils - Part 3: Black leads - Bending strengths of HB leads 1 Scope This part of IS0 9177 specifies bending strengths and a test method for black leads of HB hardness degree used for mechanical pencils for technical drawings. 2 Normative reference The f

15、ollowing standard contains provisions which, through reference in this text, constitute provisions of this part of IS0 9177. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of IS0 9177 are encouraged to

16、investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 9177-2: 1989, Mechanical pencils - Part 2: Black leads - Classification and dimensions. 3 Definitions For the pur

17、poses of this part of IS0 9177 the defi- nitions given in IS0 9177-2 as well as the following definition apply. 3.1 bending strength: Quality requirement of lead strength as determined by bending the lead to its breaking point, using a prescribed test method and formula. 4 Bending strength 4.1 Gener

18、al Bending strength of HB leads used for mechanical pencils shall be tested in accordance with clause 5 and shall satisfy the requirements specified in 4.2. 4.2 Bending strength of HB leads for mechanical pencils The bending strength (0) shall be not less than the value specified in table 1 correspo

19、nding to the re- spective nominal diameter. 1 SANS 9177-3:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .IS0 9177=3:1994(E) 43 IS0 Lead type Table 1 - Bending strength of HB leads for mechanical pencils Nominal diameter mm Minimum bendin

20、g strength, G MPa Polymer (P) 0,35 1) 240 05 I 190 07 I 160 1 1) 95 Ceramic (C) 2 70 1) Current practice is to label or mark mechanical pencils and boxes 0,3 and 0,9 as applicable. The user should note that leads with new standardized designations apply perfectly well to mechanical pencils with the

21、old designations and vice versa; i.e. 0,35 and 1 correspond respectively to 0,3 and 0,9. 5 Test method On a lead sample taken at random, bending strength shall be tested as follows: Arrange the lead test piece as shown in figures 1 and 2 and apply a load on the lead at a distance halfway between the

22、 two supporting anvils at the following rates (+ 10 %): 0,5 N/s for 2 mm nominal diameter lead; 0,l N/s for 0,35 mm, 0,5 mm, 0,7 mm and 1 mm nominal diameter leads. These loading rates shall be verified beforehand using a rigid test piece instead of a lead. Determine the load (F) at which the lead h

23、as broken and use this value to calculate the bending strength (a) according to the following formula: 8Fl 0 =- xd3 where CT is the bending strength, in megapascals; F is the load, in newtons; 1 is the distance, in millimetres, between the two supporting anvils according to ta- ble 2; d is the actua

24、l diameter of the lead, in milli- metres. Figure 1 - Arrangement for bending strength test SANS 9177-3:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .Q IS0 IS0 9177=3:1994(E) . . . . R 0,2 *to,02 Dimensions in millimetres R 0,2 *0,02 / F

25、igure 2 - Anvils for bending strength test Table 2 - Distance between the two supporting anvils Dimensions in miliimetres 6 Test report d) test values for F and I; The test report shall contain the following information: a) reference to this part of IS0 9177; b) lead type (P or C); e) bending streng

26、th as evaluated according to clause 5; f) name of test centre, date and signature of person carrying out the test. c) actual diameter (relating to the nominal diameter) of lead under test; 3 SANS 9177-3:2009This s tandard may only be used and printed by approved subscription and freemailing clients

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