1、December 2016 English price group 8No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 21.060.10!%dS“2655948www.din.deD
2、IN 7516Thread cutting screws Cross recessed head screws Dimensions, requirements, testing,English translation of DIN 7516:2016-12Gewinde-Schneidschrauben Kreuzschlitzschrauben Mae, Anforderungen, Prfung,Englische bersetzung von DIN 7516:2016-12Vis auto-taraudeuses Vis empreinte cruciforme Dimensions
3、, exigences, essai,Traduction anglaise de DIN 7516:2016-12SupersedesDIN 7516:1995-09www.beuth.deDocument comprises 12 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.05.17 DIN 7516:2016-12 2 A comma is used as the decimal marke
4、r. Contents Page Foreword . 3 1 Scope 4 2 Normative references 4 3 Dimensions and designation . 5 4 Requirements 7 4.1 General requirements 7 4.2 Design and dimensional accuracy . 7 4.3 Material . 7 4.4 Thread . 7 4.5 Surface finish . 7 4.6 Metallurgical properties . 7 4.6.1 Surface hardness 7 4.6.2
5、 Case depth 7 4.6.3 Core hardness . 8 4.6.4 Microstructure 8 4.7 Mechanical properties . 8 4.7.1 Thread cutting capability . 8 4.7.2 Torsional strength . 8 4.7.3 Tensile strength . 8 5 Testing . 8 5.1 Testing of metallurgical properties 8 5.1.1 Determination of surface hardness 8 5.1.2 Determination
6、 of case depth . 8 5.1.3 Determination of core hardness 8 5.1.4 Examination of microstructure 8 5.2 Testing of mechanical properties 9 5.2.1 Drive test . 9 5.2.2 Torsional strength test 9 5.2.3 Tensile test . 11 Bibliography . 12 DIN 7516:2016-12 3 Foreword This standard has been prepared by Working
7、 Committee NA 067-00-05 AA Kleinschrauben und gewindeformende Schrauben of DIN-Normenausschuss Mechanische Verbindungselemente (DIN Standards Committee Fasteners). The DIN 4000-160-11 tabular layout of product properties applies to screws covered in this standard. Attention is drawn to the possibili
8、ty that some of the elements of this document may be the subject of patent rights. DIN and/or DKE shall not be held responsible for identifying any or all such patent rights. Amendments This standard differs from DIN 7516:1995-09 as follows: a) normative references have been updated; b) table headin
9、gs have been rendered more precise; c) a Bibliography has been added; d) the standard has been editorially revised. Previous editions DIN 7516: 1959-08, 1971-08, 1986-11, 1995-09 DIN 7516:2016-12 4 1 Scope This standard specifies requirements for heat-treated thread cutting screws (cross recessed he
10、ad screws) with an ISO metric thread as specified in DIN ISO 261, with cutting flutes extending from the point of the screw to its head, and designed to cut their mating thread during assembly. For head styles of the screws, see the relevant DIN Standards in Clause 3. See DIN ISO 8992 for general re
11、quirements and DIN EN ISO 3269 for acceptance inspection. The specifications of this standard are intended to ensure that thread cutting screws, provided that they are not overstressed, are capable of performing the above functions without fracturing or their own thread being deformed. To that end,
12、requirements for assessing mechanical and functional characteristics of thread cutting screws have been specified for the following: surface hardness; minimum torque; minimum ultimate tensile load; thread cutting capability. 2 Normative references The following documents, in whole or in part, are no
13、rmatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. DIN EN 10083-2, Steels for quenching and tempering Part 2:
14、Technical delivery conditions for non alloy steels DIN EN 10084, Bright steel products Technical delivery conditions DIN EN 10263-3, Steel rod, bars and wire for cold heading and cold extrusion Part 3: Technical delivery conditions for case hardening steels DIN EN 10263-4, Steel rod, bars and wire f
15、or cold heading and cold extrusion Part 4: Technical delivery conditions for steels for quenching and tempering DIN EN ISO 2639, Steels Determination and verification of the depth of carburized and hardened cases DIN EN ISO 3269, Fasteners Acceptance inspection DIN EN ISO 4042, Fasteners Electroplat
16、ed coatings DIN EN ISO 4757, Cross recesses for screws DIN EN ISO 4759-1, Tolerances for fasteners Part 1: Bolts, screws, studs and nuts Product grades A, B and C DIN EN ISO 6507-1, Metallic materials Vickers hardness test Part 1: Test method DIN EN ISO 6507-4, Metallic materials Vickers hardness te
17、st Part 4: Tables of hardness values DIN EN ISO 7045, Pan head screws with type H or type Z cross recess Product grade A DIN 7516:2016-12 5 DIN EN ISO 7046-1, Countersunk flat head screws (common head style) with type H or type Z cross recess Product grade A Part 1: Steel screws of property class 4.
18、8 DIN EN ISO 7047, Raised countersunk head screws (common head style) with type H or type Z cross recess Product grade A DIN ISO 261, ISO general purpose metric screw threads General plan DIN ISO 965-1, ISO general purpose metric screw threads Tolerances Part 1: Principles and basic data DIN ISO 899
19、2, Fasteners General requirements for bolts, screws, studs and nuts 3 Dimensions and designation For dimensions see Table 1, Table 2 and Figure 1. Table 1 Screw types and designations Type Figure Type of cross recess as in DIN EN ISO 4757 Other dimensions as in Example of designationaAE recess H Z D
20、IN EN ISO 7045 Thread cutting screw DIN 7516 AE M5 null 20 St H DE recess H Z DIN EN ISO 7046-1 Thread cutting screw DIN 7516 DE M5 null 20 St H EE recess H Z DIN EN ISO 7047 Thread cutting screw DIN 7516 EE M5 null 20 St H aIf the designation does not include the symbol H or Z identifying the cross
21、 recess, recess type H shall apply. DIN 7516:2016-12 6 The edge of the core hole on the insertion side shall be sharp-edged. a) Thread end b) Thread core hole Figure 1 Dimensions (notation) Table 2 Range of commercial sizes and core hole diameters Dimensions in millimetres Thread size, d M3 M4 M5 M6
22、 M8 Nominal length, laRange of commercial sizesb6 c 8 c 10 c 12 c (14) c 16 (18) 20 (22) 25 30 35 40 Core hole diameterddhH11 2,7 3,6 4,5 5,5 7,4 aBracketed sizes should be avoided if possible. bThe zone between the continuous thick lines indicates the range of commercial sizes. Only screws of these
23、 lengths are covered by this standard. cNot for types DE and EE. dDesigned for workpieces made from materials of medium strength. For thin-walled workpieces or workpieces made from soft materials, a smaller core hole diameter may be chosen, and for thick-walled workpieces or workpieces made from har
24、d materials, a larger core hole diameter may be used. It is recommended that the selection be made on the basis of tests. The depth of engagement should not exceed 2d. DIN 7516:2016-12 7 4 Requirements 4.1 General requirements For general requirements, DIN ISO 8992 shall apply. 4.2 Design and dimens
25、ional accuracy DIN EN ISO 4759-1, product grade A shall apply with regard to the design and dimensional accuracy of thread cutting screws unless otherwise specified in the relevant dimensional standards. 4.3 Material Thread cutting screws shall be made of case hardening steel as specified in DIN EN
26、10084 or quenched and tempered steel as specified in DIN EN 10083-2 (symbol St) at the manufacturers discretion. See DIN EN 10263-3 and DIN EN 10263-4 for steels for screws. The use of other materials shall be subject to agreement. 4.4 Thread The thread of thread cutting screws shall be such that th
27、e thread formed is capable of accommodating a screw with ISO metric screw thread complying with DIN ISO 965-1 and produced to tolerance 6h. The type of thread and thread tolerance for the screws shall be at the manufacturers discretion. 4.5 Surface finish DIN EN ISO 4042 applies with regard to elect
28、roplating. Other surface finishes shall be subject to agreement. 4.6 Metallurgical properties 4.6.1 Surface hardness The surface hardness of thread cutting screws shall be at least 450 HV 0,3 after heat treatment. 4.6.2 Case depth The case depth of screws shall comply with the values specified in Ta
29、ble 3. Table 3 Case depth Dimensions in millimetres Thread size, d Case depth Eht 450 min. max. M3 0,05 0,18 M4 and M5 0,10 0,25 M6 and M8 0,15 0,28 DIN 7516:2016-12 8 4.6.3 Core hardness The core hardness of thread cutting screws shall be between 240 HV 5 and 370 HV 5 after heat treatment. 4.6.4 Mi
30、crostructure The microstructure of thread cutting screws shall show no band of free ferrite between core and case after heat treatment. 4.7 Mechanical properties 4.7.1 Thread cutting capability Thread cutting screws shall be capable of cutting a mating thread when driven into a test plate as specifi
31、ed in 5.2.1, without their own thread being deformed. 4.7.2 Torsional strength The torsional strength of thread cutting screws shall be such that, when tested in accordance with 5.2.2, the torque necessary to cause failure (breaking torque) is equal to or greater than the minimum values specified in
32、 Table 5. 4.7.3 Tensile strength The tensile strength of thread cutting screws shall be such that, when tested in accordance with 5.2.3, the minimum ultimate tensile load necessary to cause failure (breaking load) is equal to or greater than the minimum values specified in Table 6. 5 Testing 5.1 Tes
33、ting of metallurgical properties 5.1.1 Determination of surface hardness Vickers surface hardness testing shall be carried out according to DIN EN ISO 6507-1 and DIN EN ISO 6507-4. The impression shall be made on a flat section of the screw, preferably on the screw head. 5.1.2 Determination of case
34、depth The case depth can be determined by examining a microsection made at the thread flank mid-point (i.e. between crest and root) with a microscope. Determination of the case depth using hardness tests is specified in DIN EN ISO 2639. 5.1.3 Determination of core hardness Vickers core hardness test
35、ing shall be carried out according to DIN EN ISO 6507-1 and DIN EN ISO 6507-4. 5.1.4 Examination of microstructure The microstructure of the screw material shall be examined metallographically. DIN 7516:2016-12 9 5.2 Testing of mechanical properties 5.2.1 Drive test The screw to be tested shall be d
36、riven into a test plate until one full-form thread projects above the surface of the other side of the plate. The thickness of the test plate shall be as specified in Table 4. Table 4 Test plate details and cutting torques Thread size, d Plate thickness Hole diameter of plate Cutting torque mm mm To
37、lerance zone H9 Nm max. M3 3 2,7 0,9 M4 4 3,6 2,1 M5 5 4,5 4,2 M6 6 5,5 7,2 M8 8 7,4 17 The Brinell hardness of the test material shall be between 110 HB and 130 HB. The carbon content of the test plate material shall not exceed 0,23 %. The core hole in the test plate may be produced by drilling, pu
38、nching and redrilling, or by reaming or piercing. The force used to drive the screw into the test plate shall not exceed 50 N for sizes up to M5, and 100 N for size M6 or greater. The driving speed shall not exceed 30 revolutions per minute. The cutting torque shall not exceed the values given in Ta
39、ble 4. Where necessary, the lubricant to be used during the drive test shall be agreed upon. NOTE If thread cutting screws are plated by the purchaser, any complaints made to the screw manufacturer need be accepted only if driving tests carried out on screws of the same consignment not subsequently
40、plated do not provide satisfactory results. 5.2.2 Torsional strength test The shank of the screw to be tested shall be clamped in a split threaded die with mating thread or in an equivalent device so that the clamped portion of the screw is not damaged. At least two full-form threads shall project a
41、bove the clamping device, and at least two full-form threads (without screw end) shall be held in the clamping device. In the case of short screws, the complete thread shall be held in the die, the screw head not resting on the device. The screw shall be tightened until fracture occurs, and the mini
42、mum breaking torques shall be established (see Table 5). DIN 7516:2016-12 10 Table 5 Minimum breaking torques Thread size, d Minimum breaking torque Nm M3 1,5 M4 3,4 M5 7,1 M6 12 M8 28 Figure 2 shows an example of a suitable test device. Key 1 Split threaded die 2 Blind hole Figure 2 Test device DIN
43、 7516:2016-12 11 5.2.3 Tensile test The screw (to be tested as a finished component) shall be clamped in a tensile testing machine and subjected to tensile stress until fracture occurs, and the minimum ultimate tensile loads shall be established as specified in Table 6. Table 6 Minimum ultimate tensile loads Thread size, d Minimum ultimate tensile load N M3 4 000 M4 7 000 M5 11 400 M6 16 000 M8 29 000 DIN 7516:2016-12 12 Bibliography DIN 4000-160, Tabular layout of product properties Part 160: Fasteners with external thread
