SANS 1700-5-3-2003 Fasteners Part 5 General requirements and mechanical properties Section 3 Mechanical properties of fasteners made of carbon steel and alloy steel - Set screws ane .pdf

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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. ICS 21.060.10 ISBN 0-626-14823-5 SANS 1700-5-3:2003 Edition 2 ISO 898-5:1998 Edition 2 SOUTH AFRICAN NATIONAL STANDARD Fasteners Part 5: General requirem

4、ents and mechanical properties Section 3: Mechanical properties of fasteners made of carbon steel and alloy steel Set screws and similar threaded fasteners not under tensile stresses This national standard is the identical implementation of ISO 898-5:1998 and is adopted with the permission of the In

5、ternational Organization for Standardization. Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa 2003 SANS 1700-5-3:2003 Edition 2 ISO 898-5:1998 Editio

6、n 2 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee STANSA TC 5120.01, Screw threads and fasteners, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This SANS edition

7、cancels and replaces the first SABS edition (SABS 1700-5-3:1996). AReference numberISO 898-5:1998(E)INTERNATIONALSTANDARDISO898-5Second edition1998-08-01Mechanical properties of fasteners madeof carbon steel and alloy steel Part 5:Set screws and similar threaded fasteners notunder tensile stressesCa

8、ractristiques mcaniques des lments de fixation en acier au carboneet en acier alli Partie 5: Vis sans tte et lments de fixation filets similaires non soumis des contraintes de tractionISO 898-5:1998(E) ISO 1998All rights reserved. Unless otherwise specified, no part of this publication may be reprod

9、ucedor utilized in any form or by any means, electronic or mechanical, including photocopying andmicrofilm, without permission in writing from the publisher.International Organization for StandardizationCase postale 56 CH-1211 Genve 20 SwitzerlandInternet isoiso.chPrinted in SwitzerlandiiForewordISO

10、 (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISOmember bodies). The work of preparing International Standards is normally carried out through ISO technicalcommittees. Each member body interested in a subject for which a technical commi

11、ttee has been established has theright to be represented on that committee. International organizations, governmental and non-governmental, in liaisonwith ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) onall matters of electrotechni

12、cal standardization.Draft International Standards adopted by the 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 ISO 898-5 was prepared by Techni

13、cal Committee ISO/TC 2, Fasteners, Subcommittee SC 1,Mechanical properties of fasteners.This second edition cancels and replaces the first edition (ISO 898-5:1980), which has been technically revised.ISO 898 consists of the following parts, under the general title Mechanical properties of fasteners

14、made of carbon steeland alloy steel: Part 1: Bolts screws and studs Part 2: Nuts with specified proof load values Coarse thread Part 5: Set screws and similar threaded fasteners not under tensile stresses Part 6: Nuts with specified proof load values Fine pitch thread Part 7: Torsional test and mini

15、mum torques for bolts and screws with nominal diameters 1 mm to 10 mmAnnex A of this part of ISO 898 is for information only.INTERNATIONAL STANDARD ISO ISO 898-5:1998(E)1Mechanical properties of fasteners made of carbon steel and alloysteel Part 5:Set screws and similar threaded fasteners not under

16、tensile stresses1 ScopeThis part of ISO 898 specifies the mechanical properties of set screws and similar threaded fasteners not under tensilestresses with nominal thread diameters from 1,6 mm up to and including 24 mm, which are made of carbon steel or alloysteel.The mechanical and physical propert

17、ies apply when tested at an ambient temperature of 10 C to 35 C and will vary athigher or lower temperatures.This part of ISO 898 does not apply to set screws requiring special properties such as specified tensile stresses (see ISO 898-1); weldability; corrosion resistance; ability to withstand temp

18、eratures above + 300 C or below 50 C.NOTE Set screws made from free-cutting steel should not be used above + 250 C.2 Normative referencesThe following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 898.At the time of publication, the edi

19、tions indicated were valid. All standards are subject to revision, and parties to agreementsbased on this part of ISO 898 are encouraged to investigate the possibility of applying the most recent editions of thestandards indicated below. Members of IEC and ISO maintain registers of currently valid I

20、nternational Standards.ISO 965-3:1998, ISO general purpose metric screw threads Tolerances Part 3: Deviations for constructional threads.ISO 4948-1:1982, Steels Classification Part 1: Classification of steels into unalloyed and alloy steels based onchemical composition.ISO 6506:1981, Metallic materi

21、als Hardness test Brinell test.ISO 6507-1:1997, Metallic materials Vickers hardness test Part 1: Test method.ISO 6508:1986, Metallic materials Hardness test Rockwell test (scales A - B - C - D - E - F - G - H - K).ISO 898-5:1998(E)ISO23 Designation systemThe property classes are designated by the sy

22、mbols shown in table 1.The numerical part of the symbol represents 1/10 of the minimum Vickers hardness.The letter H in the symbol refers to hardness.Table 1 Designations of property classes in relation to Vickers hardnessProperty class 14H 22H 33H 45HVickers hardness, HV min. 140 220 330 4504 Mater

23、ialsSet screws shall be made of steel conforming to the requirements specified in table 2.For property class 45H, other materials may be used provided that the proof torque requirements in 6.3 are met.Table 2 Steel specificationsProperty class Material Heat treatment Chemical composition% (m/m)CPSma

24、x. min. max. max.14H Carbon steel 1, 2) 0,50 0,11 0,1522H Carbon steel 3)Quenched and tempered 0,50 0,05 0,0533H Carbon steel 3)Quenched and tempered 0,50 0,05 0,0545H Alloy steel 3, 4)Quenched and tempered 0,50 0,19 0,05 0,051) Free-cutting steel may be used, with lead content 0,35 % maximum, phosp

25、horus content 0,11 % maximum and sulphur content0,34 % maximum.2) Case hardening is allowed in the case of square-head set screws.3) Steel with lead content 0,35 % maximum may be used.4) Shall contain one or more of alloying elements chromium, nickel, molybdenum, vanadium or boron, see ISO 4948-1.IS

26、OISO 898-5:1998(E)35 Mechanical propertiesWhen tested by the methods specified in clause 6, the set screws shall have, at ambient temperature, the mechanicalproperties specified in table 3.Table 3 Mechanical propertiesMechanical properties Property class1)14H 22H 33H 45HVickers hardness HV 10 min. 1

27、40 220 330 450max. 290 300 440 560Brinell hardness HB, F = 30 D2min. 133 209 314 428max. 276 285 418 532HRB min. 75 95 Rockwell hardness max. 1052)HRC min. 2)33 45max. 30 44 53Torque strength see table 5Minimum height of non-decarburized thread zone, E 121H231H341HMaximum depth of complete decarburi

28、zation, G mm 0,015 0,0153)Surface hardness HV 0,3 max. 320 450 5801) Property classes 14H, 22H and 33H are not for hexagon socket set screws.2) For property class 22H, it is necessary to test the minimum value in HRB and the maximum value in HRC, if Rockwell hardnessis tested.3) No complete decarbur

29、ization permitted in property class 45H.6 Test methods for determination of mechanical properties6.1 Hardness testsHardness tests shall be conducted as near as practicable to the centre position of the point end of the screw. If the maximumhardness as given in table 3 is exceeded, a retest shall be

30、conducted on a cross-section 0,5 d back from the point end whered is the nominal thread diameter. In case of doubt, the Vickers hardness test is decisive for acceptance.Hardness readings for the surface hardness shall be taken on the end of the screw, which will be prepared by slightlygrinding or po

31、lishing to ensure reproducible readings.6.1.1 Vickers hardness testThe Vickers hardness test shall be carried out in accordance with the provisions of ISO 6507-1.6.1.2 Brinell hardness testThe Brinell hardness test shall be carried out in accordance with the provisions of ISO 6506.ISO 898-5:1998(E)I

32、SO46.1.3 Rockwell hardness testThe Rockwell hardness test shall be carried out in accordance with the provisions of ISO 6508.6.2 Decarburization test evaluation of the surface carbon conditionUsing the appropriate measuring method (6.2.2.1 or 6.2.2.2 as applicable), the longitudinal section of the t

33、hread shall beexamined to determine that the height of the zone of base metal (E) and the depth of the zone with complete decarburization(G) are within specified limits, (see figure 1). The minimum values for E and the maximum values for G are specified intable 3.Key1 Completely decarburized2 Partia

34、lly decarburized3 Pitch line4 Base metalH1is the external thread height in the maximum metal conditionFigure 1 Zones of decarburization6.2.1 Definitions6.2.1.1 base metal hardness: Hardness closest to the surface (when traversing from core to outside diameter) just beforean increase or decrease occu

35、rs denoting carburization or decarburization.6.2.1.2 decarburization: Generally, loss of carbon at the surface of commercial ferrous materials (steels).6.2.1.3 partial decarburization: Decarburization with loss of carbon sufficient to cause a lighter shade of temperedmartensite and significantly low

36、er hardness than that of the adjacent base metal, however without showing ferrite grainsunder metallographic examination.6.2.1.4 complete decarburization: Decarburization with sufficient carbon loss to show only clearly defined ferrite grainsunder metallographic examination.6.2.1.5 carburization: Pr

37、ocess of increasing surface carbon to a content above that of the base metal.ISOISO 898-5:1998(E)56.2.2 Measurement methods6.2.2.1 Microscopic methodThis method allows the determination of both E and G.The specimens to be used are longitudinal sections taken through the thread axis approximately hal

38、f a nominal diameterfrom the end of the screw, after all heat treatment operations have been performed on the product. The specimen shall bemounted for grinding and polishing in a clamp or plastic mount, the latter being the preferred method.After mounting, grind and polish the surface in accordance

39、 with good metallographic practice.Etching in a 3 % nital (concentrated nitric acid in ethanol) solution is usually suitable for showing changes in microstructurecaused by decarburization.Unless otherwise agreed between the interested parties, a 100 magnification shall be used for examination.If the

40、 microscope is of a type with a ground glass screen, the extent of decarburization can be measured directly with ascale. If an eyepiece is used for measurement, it should be of an appropriate type, containing a cross-hair or a scale.6.2.2.2 Hardness method (referee method for partial decarburization

41、 and carburization)The decarburization test by the hardness measurement method is applicable only for threads with pitches, P, of 1,25 mmand larger, except for property class 45H, where it is applicable for all sizes.The hardness measurements are made at three points in accordance with figure 2. Val

42、ues for E are given in table 4. Theload shall be 300 g.Dimensions in millimetresHV2 HV1 30HV31,13 sminand a hardness of 55 HRC to 60 HRC, engaging the full depth of the set screw socket, the screw shall withstandthe proof torque given in table 5 without splitting or cracking.For this proof torque te

43、st, a calibrated torque measuring instrument shall be used.Visual marks at the socket due to torque testing shall not be cause for rejection.7 Marking7.1 Marking of set screws with the property classMarking of set screws with property classes as described in clause 3 is not generally required. If in

44、 special cases marking isagreed between the interested parties the symbol of the property class should be used as the marking symbol.7.2 Trade markingThe manufacturers identification marking is not required.ISO 898-5:1998(E)ISO8Annex A(informative)Bibliography1 ISO 898-1:1998, Mechanical properties of fasteners made of carbon steel and alloy steel Part 1: Bolts, screwsand studs.2 ISO 6507-2:1997, Metallic materials Vickers hardness test Part 2: Verification of testing machines.