ISO INTERNATIONAL STANDARD 898-7 First edition 1992-11-01 Mechanical properties of fasteners Part 7: Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm Caracteristiques mecaniques des éléments de fixation - Partie 7: Essai de torsion et couples minimaux de rupture des vis de diametre nominai de filetage de 1 mm a 10 mm Reference number ISO 898-7:1992(E) Not for Resale ISO 898-7:1992(E) Foreword IsO (the International Organization for Standardization) is a woridwide 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 which a technical committee has been established has the right to be represented on that committee. International organizations, govern- work. IsO collaborates closely with the International Electrotechnica! Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. . Publication as an Inter- bodies casting a vote. International Standard isO 898-7 was prepared by Technical Committee ISo/TC 2, Fasteners, Sub-Committee sC 1, Mechanical properties of fasteners. iso 898 consists of the following parts, under the general title Mechan- ical properties of fasteners: 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 tensite stresses Part 6: Nuts with specified proof ioad values - Fine pitch thread with nominal diameters 1 mm to 10 mm Annex A of this part of isO 898 is for information only. 1992 All rights reserved. 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 permission in writing from the publisher. International Organization for Standardization Case Postale 56 · CH-1211 Geneve 20 · Switzerland Printed in Switzerland censefromIHS Not for Resale ISO 898-7:1992(E) INTERNATIONAL STANDARD Mechanical properties of fasteners Part 7: Torsional test and minimum torgues for bolts and screws with nominal diameters 1 mm to 10 mm Scope 3.2 Apparatus This part of iso 898 specifies a torsional test for the determination of the breaking torque of bolts and screws with nominal diameters 1 mm to 10 mm with Test device for torsional test, such as is 3.2.1 property classes 8.8 to 12.9 in accordance with shown in figure 1. iso 898-1. The test applies to bolts and screws with thread less than M3 for which no breaking and proof foads are indicated in Iso 898-1, as well as'to short bolts and screws with nominal diameters 3 mm to Torquemeter, with a scale which shall not ex- 3.2.2 10 mm which cannot be subjected to a tensile test. ceed 'the 'quintuple of the respective minimum breaking torque. The maximum inaccuracy of the The minimum breaking torques are not valid for torquemeter shall be ± 7 % of the minimum break- hexagon socket set screws. ing torque to be tested. Normative reference The following standard contains provisions which through reference in this text, constitute provisions Test conditions 3.3 of this part of isO8g8.At the time of publication,the edition indicated was valid. All standards are sub- The bolt or screw shall be exclusively subjected to ject to revision, and parties to agreements based on torsion whereby the respective minimum breaking this part of iso 8g8 are encouraged to investigate torque according to table 2 shall be reached before the possibility of applying the most recent edition of rupture occurs. The test result shall not be influ- the standard indicated below. Members of iEc and enced by head friction or by thread friction. iso maintain registers of currently .valid Inter- : national Standards Is0 898-1:1988, Mechanical properties of fasteners - Part 1: Bolts, screws and