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 0-626-15637-8 SANS 1700-5-6:1996 Edition 1 and nat. amdt 1 ISO 2702:1992 Edition 2 Any reference to SABS 1700-5-6 is deemed to be a re
4、ference to this standard (Government Notice No. 1373 of 8 November 2002) SOUTH AFRICAN NATIONAL STANDARD Fasteners Part 5: General requirements and mechanical properties Section 6: Heat-treated steel tapping screws This national standard is the identical implementation of ISO 2702:1992 and is adopte
5、d with the permission of the International 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 SANS 1700-5-6:1996 Editi
6、on 1 and nat. amdt 1 ISO 2702:1992 Edition 2 Table of changes Change No. Date Scope Nat. amdt 1 2004 Amended to change the designation of SABS standards to SANS standards with no technical changes. Abstract Specifies the characteristics of heat-treated steel tapping screws, with tapping screw thread
7、 from ST2,2 to ST8 inclusive in accordance with ISO 1478. Keywords fasteners, heat-treatable steels, mechanical properties of materials, screws (bolts), specifications, tapping (threads), torsional strength National foreword This South African standard was approved by National Committee StanSA TC 51
8、20.01, Screw threads and fasteners, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This edition is technically identical to SABS 1700-5-6:1996. INTERNATIONAL STANDARD 2702 Second edition 1992-04-0 1 Heat-treated steel tapping screws - Me
9、chanical properties Ws 21 t6ie en acier traite thermiquement - Caracteristiques mecaniques Reference number ISO 2702: 1992(E) ISO 2702:1992(E) Foreword ISO (the international Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodies). The work of pre
10、paring International Standards is normally carried out through ISO technical committees. Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental,
11、in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Pub
12、lication as an Inter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 2702 was prepared by Technical Committee ISO/TC 2, Fasteners, Sub-Committee SC 1, Mechanical properties of fasteners. This second edition cancels and replaces th
13、e first edition (ISO 2702:1974), which has been technically revised. 0 ISO 1992 All rights reserved. No gart of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher
14、. International Organization for Standardization Case Postale 56 l CH-1211 Geneve 20 * Switzerland Printed in Switzerland ii ISO 2702:1992(E) lntroduction The Primar-y objective of this International Standard is to ensure that tapping screws will form mating threads in materials into which they are
15、normally driven without deforming their own thread and without break- ing during assembly or Service. . . . Ill This page intentionally left blank INTERNATIONAL STANDARD ISO 2702:1992(E) Heat-treated steel tapping screws - Mechanical properties 1 Scope This International Standard specifies the chara
16、cter- istics of heat-treated steel tapping screws, with tapping screw thread from ST2,2 to ST8 inclusive in accordance with ISO 1478, together with the corre- sponding test methods. 2 Normative references The following Standards contain provisions which, through reference in this text, constitute pr
17、ovisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All stan- dards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of ap- plying the most recent editions of th
18、e Standards in- dicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 1478: 1983, Tapping screws thread. ISO 65071:1982, Metallic materials - Hardness test - Vickers test - Part 1: HV 5 to HV 100. ISO 6507-2:1983, Metallic materials - Hardness test
19、- Vickers test - Part 2: HV O,2 to less than HV 5. 3 Materials 4.2 Mechanical requirements Tapping screws shall be made from cold heading, case hardening quality steel. 4 Requirements 4.1 Metallurgical requirements 4.1 .l Surface hardness The minimum surface hardness after heat treatment shall be 45
20、0 HV 0,3 (see ISO 6507-2). 4.1.2 Case depth The case depth shall conform to the values given in table 1. Table 1 - Case depth Dimensions in millimetres Thread ST2,2, ST2,6 ST2,9, ST3,3, ST3,S ST3,9, ST4,2, ST4,8, ST5,S ST6,3, ST8 Case depth min. max. 0,04 0,lO 0,05 0,18 0,lO 0,23 0,15 0,28 4.1.3 Cor
21、e hardness The core hardness af?er heat treatment shall be 270 HV 5 to 390 HV 5 for threads S ST3,9, and 270 HV 10 to 390 HV 10 for threads ST4,2. 4.1.4 Microstructure The microstructure shall show no band of free ferrite between the case and core. 4.2.1 Thread-forming capability Tapping screws shal
22、l form a mating thread without deforming their own thread when driven into a test plate, in accordance with 6.2.1. 4.2.2 Torsional strength Tapping screws shall have a torsional strength such that the torque necessary to Cause failure, when tested in accordance with 6.2.2, shall equal or ex- ceed th
23、e minimum torque values given in table 3 for the applicable screw threads. ISO 2702:1992(E) 5 Acceptance For routine acceptance tests, the drive test, torsional test and core hardness test may be used, but for referee purposes all requirements specified in this International Standard shall be satisf
24、ied. 6 Test methods 6.1 Test methods for the metallurgical requirements 6.1.1 Surface hardness test Vickers hardness test shall be carried out in ac- cordante with ISO 6507-2. The impression of the pyramid shall be made on a flat face, for preference on the screw head. 6.1.2 Case depth (microscopic
25、test) Case depth shall be measured at the thread flank mid-Point between crest and root or, in the case of smaller tapping screws up to ST3,9, in the root of the thread. For referee purposes, a micro hardness plot shall be made using a Vickers indenter and a 300 g load on the thread Profile of a pro
26、perly prepared metallographic specimen. The case depth shall be the Point at which the hardness recorded is 30 HV above the actual core hardness. 6.1.3 Core hardness test Vickers core hardness test shall be carried out in accordance with ISO 65074 at the mid-radius of a transverse section through th
27、e screw taken at a distance sufficiently behind the Point of the screw to be through the full minor diameter. 6A .4 Microstructure test The microstructure test shall be carried out by metallographic examination. 6.2 Test methods for the mechanical requirements 6.2.1 Drive test The Sample screw (coat
28、ed or uncoated, as received) shall be driven into a test plate until a thread of full diameter is completely through the test plate. The test plate shall be made from low carbon steel with a carbon content not exceeding 0,23 %. The hardness of the plate shall be 130 HV to 170 HV measured in accordan
29、ce with ISO 6507-1 and ISO 6507-2. The thickness of the plate shall conform to the values given in table 2. The test hole shall be drilled, or punched and re- drilled, or reamed to the hole diameter specified in table 2 for the size of screw being tested. Table 2 - Standard test plate thickness and
30、hole diameter for drive test Dimensions in millimetres Thread ST2,2 1,17 1,30 1,905 1,955 ST2,6 1,17 1,30 2,185 2,235 ST2,9 1,17 1,30 2,415 2,465 ST3,3 l,l7 1,30 2,68 2,73 ST3,5 1,85 2,06 2,92 2,97 ST3,9 1,85 2,06 3,24 3,29 ST4,2 1,85 2,06 3,43 3,48 ST4,8 3,lO 3,23 4,015 4,065 ST5,S 3,lO 3,23 4,735
31、4,785 In cases where screws are plated subsequent to delivery to the purchaser (or where plating of screws is otherwise under the control of the pur- chaser), the Producer is not responsible for failure due to plating. In such cases, the bolt manufacturer tan only be held responsible if it is proved
32、 that the failure is not due to any post-treatment. Screws from which the plating has been stripped off cannot be considered as samples. 2 ISO 2702:1992(E) Split threaded insert Figure 1 - Torsional test apparatus 6.2.2 Torsional strength test The shank of the Sample screw (coated or uncoated, as re
33、ceived) shall be clamped in a mating, Split, threaded die or other device so that the clamped Portion of the screw is not damaged and at least two full threads project above the clamping device and at least two full-form threads exclusive of Point are held within the clamping device. A threaded inse
34、rt with a blind hole may be used in place of the clamping device (see figure 1) provided that the hole depth is such as to ensure that breakage will occur beyond the Point. By means of a suitable calibrated torque-measuring device, torque shall be applied to the screw until failure occurs. The screw shall meet the minimum torsional strength requirements given in table 3. Table 3 - Torsional strength I Thread Minimum torsional strength N-m ST2,2 0,45 ST2,6 079 I Cl-3 9 1.5 CTA fl I 63 I I v IT,V ST5,5 I -7- 10 ST6,3 13,6 I ST8 30,5 I 3
