1、BRITISH STANDARD BS EN ISO 7085:1999 Mechanical and performance requirements of case hardened and tempered metric thread rolling screws The European Standard EN ISO 7085:1999 has the status of a British Standard ICS 21.060.10BSENISO7085:1999 This British Standard, having been prepared under the dire
2、ctionof the Engineering SectorCommittee, was publishedunder the authority ofthe Standards Committee andcomes into effect on 15November 1999 BSI 04-2000 ISBN 0 580 35010 X National foreword This British Standard is the English language version of EN ISO 7085:1999. Itis identical with ISO 7085:1999. T
3、he UK participation in its preparation was entrusted by Technical Committee FME/9, Bolts, nuts and accessories, to Subcommittee FME/9/2, Slotted and recessed head screws, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committe
4、e any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-refer
5、ences Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with their corresponding European publications. The British Standards which implement these international or European publications may be found
6、 in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards
7、are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN ISO title page, page 2, the ISO title page, pages ii to iv
8、, pages 1 to 6, aninside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSENISO7085:1999 BSI
9、04-2000 i Contents Page National foreword Inside front cover Foreword 2 Foreword iii Text of ISO 7085 1ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7085 September 1999 ICS 21.060.10 English version Mechanical and performance requirements of case hardened and tempered metric threa
10、d rolling screws (ISO 7085:1999) Caractristiques mcaniques et fonctionnelles des vis autotaraudeuses par dformation, filetage mtrique, cmentes et revenues (ISO7085:1999) Mechanische und funktionelle Eigenschaften von einsatzgehrteten und angelassenen metrischen gewindefurchenden Schrauben (ISO 7085:
11、1999) This European Standard was approved by CEN on 24 July 1999. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical
12、references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN memb
13、er into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, CzechRepublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portug
14、al, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for
15、 CEN national Members. Ref. No. EN ISO 7085:1999 EENISO7085:1999 BSI 04-2000 2 Foreword The text of the International Standard ISO7085:1999 has been prepared by Technical Committee ISO/TC2 “Fasteners” in collaboration with Technical Committee CEN/TC 185 “Threaded and non-threaded mechanical fastener
16、s and accessories”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March2000, and conflicting national standards shall be withdrawn at the latest by March
17、2000. According to the CEN/CENELEC Internal-Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norwa
18、y, Portugal, Spain, Sweden, Switzerland and the UnitedKingdom. Endorsement notice The text of the International Standard ISO7085:1999 was approved by CEN as a European Standard without any modification. NOTENormative references to International Standards are listed in Annex ZA (normative).ENISO7085:
19、1999 ii BSI 04-2000 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Materials 1 4 Mechanical properties 1 5 Test methods 2 6 Torque wrenches 5 7 Marking 5 Bibliography 6 Annex ZA (normative) Normative references to international publications with their relevant European publications
20、Inside back cover Figure 1 Places where the case hardness may be measured 3 Figure 2 Place where the case depth may be measured 3 Figure 3 Typical test device for the torsional test 3 Figure 4 Ductility test 4 Table 1 Chemical composition 1 Table 2 Mechanical properties 1 Table 3 Mechanical and perf
21、ormance requirements 2 Table 4 Case Depth 2 Table 5 Test plate thickness and hole diameter 4ENISO7085:1999 BSI 04-2000 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International
22、 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, governmental and non-governmental, in liaison with ISO, a
23、lso take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards ado
24、pted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO 7085 was prepared by Technical Committee ISO/TC2, Fasteners, Subcommittee1, Mecha
25、nical properties of fasteners.iv blankENISO7085:1999 BSI 04-2000 1 1 Scope This International Standard specifies the requirements for case hardened and tempered metric thread rolling screws. Thread rolling screws according to this International Standard produce female threads which fit ISO general p
26、urpose metric screw threads, in the range from2mm up to and including12mm nominal thread diameter, for use in general engineering applications. ISO 898-1 is not applicable to screws made according to this International Standard. 2 Normative references The following normative documents contain provis
27、ions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate
28、 the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 898-2:1992, Mechanical
29、 properties of fasteners Part 2: Nuts with specified proof load values Coarse thread. ISO 965-3:1998, ISO general purpose metric screw threads Tolerances Part 3: Deviations for constructional screw threads. ISO 4042:1999, Fasteners Electroplated coatings. ISO 5954:1998, Cold-reduced carbon steel she
30、et according to hardness requirements. ISO 6507-1:1997, Metallic materials Vickers hardness test Part 1: Test method. ISO 15330:1999, Fasteners Preloading test for the detection of hydrogen embrittlement Parallel bearing surface method. 3 Materials The thread rolling screws shall be made from cold h
31、eading, case hardening quality steel; the chemical composition given inTable 1 is given for guidance only. Table 1 Chemical composition 4 Mechanical properties 4.1 Survey A survey of mechanical properties and of respective clauses for testing is given inTable 2. Table 2 Mechanical properties 4.2 Hea
32、t treatment Finished screws shall be case hardened and tempered at a minimum tempering temperature of340 C in order to meet all the mechanical and performance requirements of this International Standard as detailed inTable 3. 4.3 Hardness The core hardness shall be 290 HV 10 to 370 HV 10, and the ca
33、se hardness shall be 450 HV 0,3 minimum. 4.4 Case depth The case depth shall be as given inTable 4. 4.5 Breaking torque The minimum breaking torque is specified in Table 3, when tested in accordance with 5.4. Failure shall not occur in the clamped threads. Analysis Composition limits % (m/m) Carbon
34、Manganese Ladle 0,15 to 0,25 0,70 to 1,65 Check 0,13 to 0,27 0,64 to 1,71 NOTEBoron content can reach 0,005% provided that non-effective boron is controlled by addition of titanium and/or aluminium. Properties Subclause/table Test reference Core hardness 4.3 5.1 Case hardness 4.3 5.2 Case depth 4.4
35、andTable 4 5.3 Torsional strength 4.5 andTable 3 5.4 Ductility 4.6 5.5 Driveability 4.7 andTable 3 5.6 Embrittlement 4.8 5.7 Core hardness after retempering 4.9 5.8 Tensile breaking load 4.10 andTable 3 5.9ENISO7085:1999 2 BSI 04-2000 4.6 Ductility There shall be no fracture at the head/shank inters
36、ection when a permanent deformation of7 is induced between the plane of the underhead bearing face and a plane normal to the axis of the screw, when tested in accordance with5.5. The test shall be regarded as satisfactory even if a crack appears in the first thread, provided that the head does not s
37、nap off. 4.7 Ability to form the mating thread The screw shall, without permanent deformation of its own thread when viewed at 10 magnification, form a mating thread in a test plate in accordance with 5.6. During the driveability test the drive torque shall not exceed the maximum values specified in
38、 Table 3. The thread formed by the screw in the test plate shall be capable of accepting a fastener threaded in accordance with ISO965-3, tolerance class6h and shall resist a proof load test in accordance with ISO898-2, property class8. Table 3 Mechanical and performance requirements Table 4 Case De
39、pth 4.8 Embrittlement For thread rolling screws there is a risk of failure due to hydrogen embrittlement, especially if they are electroplated. Therefore, process investigation shall be conducted using a test to detect hydrogen embrittlement, by the “Parallel bearing surface method” according to ISO
40、15330 in order to be sure that the process with regard to embrittlement is under control. If embrittlement is discovered, modification of the manufacturing process will be necessary. In the case of electroplating, hydrogen embrittlement relief treatment in accordance with ISO4042 shall be applied. N
41、OTENon-electrolytic applied coatings, e.g. in accordance with ISO 10683, are preferred. 4.9 Core hardness after retempering The reduction in core hardness after retempering in accordance with the test procedure described in 5.8 shall not exceed20HV. 4.10 Tensile breaking load Tensile testing for scr
42、ews having lengths equal to or longer than12mm or3times the nominal thread diameter may be carried out by agreement between the purchaser and the supplier. NOTEThe minimum tensile breaking loads in Table 3 are given for information only. 5 Test methods 5.1 Core hardness test Core hardness shall be d
43、etermined at the mid-radius of a transverse section through the screw taken at a distance sufficiently behind the point of the screw to be through the full minor diameter. The test shall comply with ISO 6507-1. 5.2 Case hardness test For routine control purposes (where case depth and geometry of the
44、 screw permit), case hardness may be measured on end, shank or head using the Vickers hardness test in accordance with ISO 6507-1 (see Figure 1). Hardness tests shall be made on screws with surface coatings after the removal of the coating. For refereeing purposes, a micro-hardness instrument with a
45、 Vickers indenter and a HV0,1 load shall be used for screws with nominal diametersW 4mm. In such cases, measurements shall be made on the thread profile of a suitably prepared longitudinal cross section and at a distance of at least 0,05mm from the edge of the specimen. For nominal thread diameters4
46、mm the test conditions shall be agreed. Nominal thread diameter Breaking torque Drive torque Tensile breaking load a mm min. Nm max. Nm min. N 2,0 0,5 0,3 1 940 2,5 1,2 0,6 3 150 3,0 2,1 1,1 4 680 3,5 3,4 1,7 6 300 4,0 4,9 2,5 8 170 5,0 10,0 5,0 13 200 6,0 17,0 8,5 18 700 8,0 42,0 21,0 34 000 10,0 8
47、5,0 43,0 53 900 12,0 150,0 75,0 78 400 a For information only. Values in millimetres Nominal thread diameter Case depth min. max. 2 and 2,5 0,04 0,12 3 and 3,5 0,05 0,18 4 and 5 0,10 0,25 6 and 8 0,15 0,28 10 and 12 0,15 0,32ENISO7085:1999 BSI 04-2000 3 5.3 Case depth test The case depth is the dist
48、ance, perpendicular to the surface, from the surface to the point at which the hardness is 30HV0,3 above the actual core hardness. For refereeing purposes, a micro-hardness plot shallbe made using a Vickers indenter and aHV0,3load on a suitably prepared metallographic specimen (seeFigure 2). 5.4 Tor
49、sional test The sample screw shall be securely clamped by suitable means (see Figure 3) with at least two full threads projecting above the clamping device, and at least two full threads exclusive of point, held within the clamping device. By means of a suitably calibrated measuring device, torque shall be applied to the screw until failure of the screw occurs. The torque required to cause failure shall be recorded as the breaking torque and shall be equal to or exceed the minimum breaking torque specified in
