1、sTD.BSI BS EN IS0 7085-ENGL It777 m Lb24bb 0808733 5TL BRITISH STANDARD Mechanical and performance requirements of case hardened and tempered metric thread rolling screws The European Standard EN IS0 7085:1999 has the status of a British Standard ICs 21.060.10 NO COPYING WITHOUT BSI PERMISSION EXCEP
2、T AS PERMITTED BY COPYRIGHT LAW BS EN IS0 7085:1999 STDmBSI BS EN IS0 708S-ENGL 1933 lb24bb9 0808732 438 = BS EN IS0 7085:1999 Amd. No. Date National foreword Comments This British Standard is the English language version of EN IS0 7085: 1999. It is identical with IS0 7085: 1999. The UK participatio
3、n in its preparation was entrusted by Technical Committee FME/s, Bolts, nuts and accessories, to Subcommittee FME/Q/2, Slotted and recessed head screws, which has the responsibility to: - aid enquirers to undersand the text; - present to the responsible internationallEuropean committee any enquiries
4、 on the interpretation, or proposals for change, and keep the UK interests MOrIIIed, - 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-references Attenti
5、on 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 in the BSI S
6、tandards Catalogue under the section entitled “International Stan- Correspondence Index“, or by using the “Find“ facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include ali the necessary provisions of a contract. Users of British Standards are responsible f
7、or 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, the EN IS0 titJe page, the EN IS0 foreword page, the IS0 title page, pages ii and iii, a blank pa
8、ge, pages 1 to 8, the annex ZA page and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. This British Standard, having been prepared under the direction of the Engineering Sector Cornmitie, was published under the authority of the Standar
9、ds Committee and comes into effect on 15 November 1999 (o BSI 11-1999 ISBN O 580 35010 X STD-BSI BS EN IS0 7085-ENGL 1999 m Lb24bb 0808733 374 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 i085 September 1999 - ICs 21.060.1 O English version Mechanical and performance requirements of case
10、 hardened and tempered metric thread rolling screws (IS0 7085:1999) Caractristiques mecaniques et fonctionnelles des vis autotaraudeuses par d6formation. B filetage mtrique, cmentes et revenues (IS0 7085:1999) Mechanische und funktionelle Eigenschaften von einsatzgehrteten und angelassenen metrische
11、n gewindefurchenden Schrauben (IS0 7085:1999) This European Standard was approved by CEN on 24 July 1999. CEN members are bound to comply with the CENICENELEC Internai Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteratio
12、n. Up-to-date lists and bibliographical 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 translatio
13、n under lhe responsibility of a CEN member 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. Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland. Ireland. Italy
14、, Luxembourg, Netherlands. Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMiITEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPAISCHEC KOMITEE FUR NORMUNG Central Secretariat rue de Stassart, 36 8-1050 Brussels 8 1999 CEN All rights of exploitation in any form
15、 and by any means reserved worldwide for CEN national Members. Ref. No. EN IS0 7085:1999 E - STD.BSI ES EN IS0 7085-ENGL 1997 1624bb9 0808734 200 = EN IS0 7086:1999 Foreword The text of the International Standard IS0 70831 999 has been prepared by Technical Committee ISOTTC 2 “Fasteners“ in collabor
16、ation with Technical Committee CENTTC 185 “Threaded and non-threaded mechanical fasteners 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
17、 March 2000, and conflicting national standards shall be withdrawn at the latest by March 2000. According to the CEWCENELEC Internal -Regulations,-the nationalstandards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark,
18、Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard IS0 7085:1999 was approved by CEN as a European Standard without any modification. NOTE:
19、Normative references to International Standards are listed in annex ZA (normative). STD-BSI BS EN IS0 7085-ENGL 1999 lsl 162Ybb9 0808735 147 = EN IS0 708lj:1999 INTERNATIONAL STANDARD IS0 7085 First edition 1999-09-01 Mechanical and performance requirements of case hardened and tempered metric threa
20、d rolling screws Caractristiques mcaniques et fonctionnelles des vis autotaraudeuses par dformation, filetage mtrique, cmentes et revenues Reference number IS0 7085:1999(E) STD.BSI ES EN IS0 7085-ENGL 1779 3bi4bb9 0808136 083 EN IS0 7085:1999 Contents Page 1 Scope 1 2 Normative references 1 3 Materi
21、als . 2 4 Mechanical properties 2 5 Test methods 4 6 Torque wrenches . 7 7 Marking . 7 Bibliography 8 STDaBSI 8s EN IS0 7085-ENGL L99q lb24bb9 0608737 TLT EN IS0 7085:1999 Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 me
22、mber 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 committee. International organizations, governme
23、ntal 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. International Standards are drafted in accordance with the rules given in the ISOAEC Direc
24、tives, Part 3. Draft Intemational 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 YO of the member bodies casting a vote. International Standard IS0 7085 was prepared by Technical
25、Committee ISOTTC 2, Fasteners, Subcommittee 1, Mechanical properties of fasteners. iii Mechanical and performance requirements of case hardened and tempered metric thread rolling screws 1 Scope This International Standard specifies the requirements for case hardened and tempered metric thread rollin
26、g screws. Thread rolling screws according to this International Standard produce female threads which fit IS0 general purpose metric screw threads, in the range from 2 mm up to and including 12 rnm nominal thread diameter, for use in general engineering applications. IS0 898-1 is not applicable to s
27、crews made according to this International Standard. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendmens to, or revisions of, any of these p
28、ublications do not apply. However, parties to agreements based on this Intemationai Standard are encouraged to investigate 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
29、 applies Members of IS0 and IEC maintain registers of currently valid International Standards. IS0 898-2: 1992, Mechanical properties of fasteners - Part 2: Nuts with specitkt paf load values - Coarse thread. IS0 965-3:1990, IS0 general purpose metric screw threads - Tolerances -pwt3: Deviations for
30、 constructional screw threads. IS0 4042:1999, Fasteners - Electroplated coatings. IS0 5954: 1998, Cold-reduced carbon steel sheet acwnling to haniness qui-. IS0 6507-1 :1997, Metallic materials - Vickers hardness test - Patt 1: Test methud. IS0 15330:1999, Fasteners - Preloading test for the detecti
31、on of hydrrigen embrimement - Padie/ bearing surface method. 1 STD-BSI BS EN IS0 7085-ENGL 1999 I 1624bh9 0808739 892 m EN IS0 7085:1999 Analysis Ladle Check 3 Materials Composition limits % (dm) Carbon Manganese 0,70 to 1,65 0,64 to 1,71 O, 15 to 0,25 O, 13 to 0,27 The thread rolling screws shall b
32、e made from cold heading, case hardening quality steel; the chemical composition given in Table 1 is given for guidance only. Table 1 - Chemical composition I NOTE Boron content can reach 0,005 % provided that non-effective boron is controlled by addition of titanium and/or I aluminium. 4 Mechanical
33、 properties 4.1 Survey A survey of mechanical properties and of respective clauses for testing is given in Table 2. Table 2 - Mechanical properties Properties Core hardness Case hardness Case depth Torsional strength Ductility Driveability Ernbrittlement Core hardness after retempering Tensile break
34、ing load Subclausehble I Test reference 4.3 4.3 4.4 and Table 4 4.5 and Table 3 4.6 4.7 and Table 3 4.8 4.9 4.10 and Table 3 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 4.2 Heat treatment Finished screws shall be case hardened and tempered at a minimum tempering temperature of 340 OC in order to meet all th
35、e mechanical and performance requirements of this Intemational Standard as detailed in Table 3. I i 4.3 Hardness l The core hardness shall be 290 HV 1 O to 370 HV 1 O, and the case hardness shall be 450 HV 0,3 minimum. 4.4 Casedepth The case depth shall be as given in Table 4. 2 STD.BS1 BS EN IS0 70
36、85-ENGL 1999 1624bh9 0808740 504 EN IS0 7085:1999 Nominal thread Breaking torque diameter mm min. Nm 2,o 05 2,s 12 3,O 2,1 3,5 3,4 44 4,9 5,O 10,o 6,O 17,O 8,O 42,O 10,o 85,O 12,o 150,O 4.5 Breaking torque Drive torque Tensile breaking loada max. min. Nm N 03 1 940 0,6 3 150 1,1 4 680 1,7 6 300 2,s
37、8 170 50 13 200 8,5 18 700 21 ,o 34 O00 43,O 53 900 750 78 400 The minimum breaking torque is specified in Table 3, when tested in accordance with 5.4. Failure shall not occur in the clamped threads. 2 and 2,5 3 and 3,5 4 and 5 6 and 8 4.6 Ductility _ 0,04 0,12 0,05 0,18 0,lO 0,25 0,15 0,28 There sh
38、all be no fracture at the headshank intersection when a permanent deformation of 7O is induced between the plane of the underhead bearing face and a plane normal to the axis of the screw, when tested in accordance with 5.5. The test shall be regarded as satisfactory even if a crack appears in the fi
39、rst thread, provided that the head does not snap off. 10 and 12 4.7 Ability to form the mating thread _ - 0,15 0,32 The screw shall, without permanent deformation of its own thread when viewed at x 10 magnification, form a mating thread in a test plate in accordance with 5.6. During the driveability
40、 test the drive torque shall not exceed the maximum values specified in Table 3. The thread formed by the screw in the test plate shall be capable of accepting a fastener threaded in accordance with IS0 965-3, tolerance class 6h and shall resist a proof load test in accordance with IS0 898-2, proper
41、ty class 8. Table 3 - Mechanical and performance requirements Table 4 - Case Depth b Values in millimetres I Nominal thread diameter I Case depth 1 I I min. I max. I 3 STD-BSI BS EN IS0 7085-ENGL 1997 9 lb24bb9 0808?4, 440 = EN IS0 7085:1999 4.8 Embiittlement For thread rolling screws there is a ris
42、k 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 IS0 15330 in order to be sure that the process with regard to emb
43、rittlement 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 IS0 4042 shall be applied. NOTE Non-electrolytic applied coatings, e.g. in accordance wi
44、th IS0 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 exceed 20 HV. 4.10 Tensile breaking load Tensile testing for screws having lengths equal to or longer than 12 mm or 3 tim
45、es the nominal thread diameter may be carried out by agreement between the purchaser and the supplier. NOTE The minimum tensile breaking loads in Table 3 are given for information only. 5 Test methods 5.1 Core hardness test Core hardness shall be determined at the mid-radius of a transverse section
46、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 IS0 6507- 1. 5.2 Case hardness test For routine control purposes (where case depth and geometry of the screw permit), case hardness may be measured on en
47、d, shank or head using the Vickers hardness test in accordance with IS0 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 Vickers indenter and a HV 0,l load shall be used f
48、or screws with nominal diameters a 4 mm. 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 0,05 mm from the edge of the specimen. For nominal thread diameters 4 mm the test conditions shall be agreed. Figur
49、e 1 - Places where the case hardness may be measured 4 STD-BSI BS EN IS0 7085-ENGL 1999 1624bb9 0808742 387 EN IS0 7085:1999 5.3 Case depth test The case depth is the distance, perpendicular to the surface, from the surface to the point at which the hardness is 30 HV 0,3 above the actual core hardness. For refereeing purposes, a micro-hardness plot shall be made using a Vickers indenter and a HV 0,3 load on a suitably prepared metallographic specimen (see Figure 2). a Only if the thread form is not totally carburized. Figure 2 - Place where t
