September 1995 Hexagon head and slotted head thread cutting screws Dimensions, requirements and testing 1es 2106010 Descriptors: Screws, thread cutting screws, fasteners, Gewinde-Schneidschrauben; Sechskantschrauben, Sct Supersedes November 1986 edition tzschrauben; MaBe, Anforderungen, Priffung 1n keeping with current practice in standards published by the International Organization for Standardization (ISO), a comma hhas been used throughout as the decimal marker. Foreword This standard has been prepared by the Normenausschu8 Mechanische Verbindungselemente (Fasteners Standards Committee). Amendments ‘The following amendments have been made to the November 1986 edition 4) The references to other DIN Standards have been updated »b) An’ has been added to each screw head type (except for type A) ©) The maximum core hardness has been reduced (to 370 HV). 4) The standard has been editorially revised, Previous editions DIN 7513: 1949-08, 1956-08, 1968-03, 1971-06, 1986-11 1. Scope and field of application This standard specifies dimensions, requirements and test methods for heat-treated hexagon head and slotted head thread cutting screws with an ISO mettic thread as speci in DIN 13-12, with cutting flutes extending from the point of the screw to its head, and designed to cut their mating thread during assembly. See the relevant DIN Standards for head styles, SO 8992 for general requirements, and 'S0 3269 for acceptance inspection The specifications of this standard are intended to ensure that thread cutting screws are capable of performing the above functions without their own thread fracturing or becoming deformed. To that end, requirements have been specified for thread cutting capability, surface hardness, tensile strength and torsional strength. 2 Normative references This standard incorporates, by dated or undated reference, provisions from other publications. These normative ret- erences are cited at the appropriate places in the text and the publications are listed hereafter. For dated refer- 324 fences, subsequent amendments to or revisions of any of these publications apply to this standard only when incor porated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies, OW 13-12 1SO metric screw threads; coarse and fine pitch threads with diameters from 1 to 300 mm; selected diameters and pitches DIN 13:15 1SO metric screw threads: fundamental deviations and tolerances for screw threads of 1 mm diameter and larger IN 1654-3 ‘Cold heading and cold extruding steels: technical delv- ‘ery conditions for case hardening steels DIN 1654-4 ‘Cold heading and cold extruding steels; technical delv- ‘ery conditions for steels for quenching and tempering DIN 4000-2 TTabular layouts of article characteristics for bol serews and nuts Continued on pages 2 to 5.Page 2 DIN 7513 DIN 17 210 ‘Case hardening steel: technical delivery conditions DIN 50133 Vickers hardness testing of metalic materials; HV 0,2 to HV 100, DIN 50 190-1 Determination of effective case depth of heat-treated parts after carburizing DIN EN 10 083-2 ‘Quenched and tempered steels; technical delivery con- ditions for unalloyed quality steels DIN EN 24 017 Hexagon head screws (So 4017 1988) DIN EN ISO 1207 Slotted cheese head screws; product grade A (SO 1207 1892) product grades A and B 3 Dimensions and designations DIN EN 1S0 2009 ‘Slotted countersunk head screws (common head style); product grade A (/SO 2008 1984) DIN EN ISO 2010 Slotted raised countersunk head screws (common head Style); product grade A (ISO 2010 : 1994) 'So 3269: 1988 Fasteners; acceptance inspection 180 4042: 1989 Threaded components; electroplated coatings 'S0 4759411978 Tolerances for fasteners; bolts, screws and nuts with thread diameters between 16 (inclusive) and 150 mm (inclusive) and product grades A, B and C 180 8992 : 1986 Fasteners: general requirements for bolts, screws, studs and nuts Table 1: Screw types and designations (Other dimensions = ——— & = OWEN 1501207 | Serew ON 7513 —BE MBX20—t See eee eee eee * = owen iso 2008 | screw ON 7513 —FEMS 20 t | ce owen iso 20% | scow Di 75:8 GEMSX 20-81 The DIN 4000 ~ 2 ~ 1 tabular layout of article characteristics shall apply to screws as covered in this standard 325DIN 7513 Page 3 Thread end Core hole “The edge of the core hole on the insertion side shall be sharp-edged Table 2: Range of commercial sizes and core hole diameters Dimensions in mm Type BE, FE and GE 1A BE, FE and GE Theadsie | M25 a ma Ms cy me ‘Nominal length, 1") Range of commercial sizes?) 6 > > 8 | 5 10 » 12 A fa 4 a Core hole diameter) dy om) 22 27 36 45 55 74 1) Bracketed sizes should be avoided if possible. 2) The zone between the continuous thick lines indicates the commercial sizes. These screws only are covered by this standard. 8) Not for types FE and GE. 4) Designed for workpieces made from materials of medium strength. For thin-walled workpieces or workpieces made trom soft materials, a smaller core hole diameter, for thick-walled workpieces or workpieces made from hard materials, a larger core hole diameter may be chosen. Itis recommended that the selection be made on the basis of tests. ‘The depth of engagement should not exceed 2d. 326Page 4 DIN 7513, 4 Requirements 4.1 General requirements Thread cutting screws shall meet the general requirements specified in 'SO 8892. 42. Design ‘The design and dimensional accuracy of thread cutting screws shall comply with ISO 4758-1, product grade A, Unless otherwise specified in the relevant dimensional standards 43° Material ‘Thread cutting screws may be made of case hardening st. 1s specified in DIN 17 210 or quenched and tempered stee! as specified in DIN EN 10 083:2, or of steels as specified in DIN 1654-9 and DIN 1654-4, use of other materials being subject to agreement. 44° Thread ‘The thread of thread cutting screws shall be such that the thread formed is capable of accommodating a screw with 180 metric screw thread complying with DIN 13-15 and produced to tolerance 6h. The form of thread and thread tolerance for the screws shall be at the manufacturer's discretion, 4.5 Surface finish 180 4042 shall apply with regard to electroplating, other types of surface finish being the subject of agreement. 4.8 Metallurgical properties 4.61 Surface hardness ‘The surface hardness of thread cutting screws shall, after heat treatment, be at least 450 HV 03. 462 Case depth The case depth of screws shall comply with the values spec- ified in table 3 Table 3: Case depth Dimensions in mm Case eon Tea se ‘ons simen Maxiam M25 0.04 | 012 wa 00s ou wenams [ovo ozs wewews [es | eae 48.3 Core hardness. ‘The core hardness of screws shall, after heat treatment, be between 240 HV § and 370 HV 5, 4.84 Microstructure The microstructure of screws shall, after heat treatment, show no band of tree ferrite between core and case 4.7 Mechanical properties 474. Thread cutting capability Thread cutting screws shall be capable of cutting a mating thread when driven into a test plate as specified in sub- clause 521, without their own thread becoming deformed. 47.2 Torsional strength The torsional strength of thread cutting screws shall be such that, when tested in accordance with subclause 522, the torque necessary to cause failure (breaking torque) is equal to oF greater than the minimum values specified in table 6. 4.7.3. Tensile strength ‘The tensile strength of thread cutting screws shall be such that, when tested in accordance with subclause 523, the torque necessary to cause failure (breaking torque) is ‘equal to oF greater than the minimum values specified in table 6. 5 Testing 5.1 Metallurgical properties 5.1.1. Determination of surface hardness ‘The surface hardness shall be determined in accordance with DIN 50 133, the impression being made on a flat sec tion of the screw, preferably on the screw head 5.1.2 Determination of case depth ‘The case depth may be determined by examining a micro- section 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 covered by DIN 50 190-1 5.1.3. Determination of core hardness The core hardness shall be determined in accordance with DIN 50133, 5.1.4 Examination of microstructure The microstructure of the screw material shall be examined ‘metallographically. 5.2. Mechanical properties 5.2.1 Drive test The drive test shall be carried out using the test assembly shown in figure 1 by way of example The screw to be tested shall be driven into a test plate until cone full-form thread projects above the surface of the plate. The test plate material shall have a carbon content not exceeding 0.23 %, its hardness being between 110 HB and {20 HB, The thickness ofthe tet pate hal be as specifed in table Table 4: Test plate details and cutting torques Hoe | Maximum Prato Twwead size | thickness, | ameter, | cutting ue 9) inNm w25 25 22 08 ws 3 a7 09 327