DIN 6935-2011 Cold bending of flat rolled steel《平轧钢冷弯》.pdf

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1、October 2011 Translation by DIN-Sprachendienst.English price group 9No 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

2、 77.140.50!%)1S“2061448www.din.deDDIN 6935Cold bending of flat rolled steel,English translation of DIN 6935:2011-10Kaltbiegen von Flacherzeugnissen aus Stahl,Englische bersetzung von DIN 6935:2011-10Cintrage froid des produits plats en acier,Traduction anglaise de DIN 6935:2011-10SupersedesDIN 6935:

3、2010-01www.beuth.deDocument comprises 13 pagesIn case of doubt, the German-language original shall be considered authoritative.11.13DIN 6935:2011-10 2 A comma is used as the decimal marker. Contents Page Foreword . 3 1 Scope . 4 2 Normative references . 4 3 Bending radii . 4 3.1 General . 4 3.2 Bend

4、ing angle and thickness s 4 4 Key to materials 6 5 Minimum leg length 6 6 Permissible deviations for angular positions on bending sections 6 7 Calculation of developed lengths . 7 8 Representation and position of bend lines for developments . 10 9 Dimensioning and calculation of developed lengths (e

5、xamples) 10 10 Development and marking of bend line position (example) 12 Bibliography . 13 DIN 6935:2011-10 3 Foreword This standard has been prepared by Working Committee NA 026-00-03 AA Stanzteile of the Normen-ausschuss Federn, Stanzteile and Blechformteile (NAFS) (Springs, Stamped Parts and Mou

6、lded Parts Standards Committee). For more information on NAFS, visit our website at www.nafs.din.de. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN shall not be held responsible for identifying any or all such patent rights.

7、Amendments This standard differs from DIN 6935:2010-01 as follows: a) the scope has been updated; b) normative references have been updated; c) figures have been provided with titles; d) Clause 3 has been changed; e) Tables 1 to 3 have been revised; f) the standard has been editorially revised. Prev

8、ious editions DIN 6935: 1958-01, 1967-05, 1969-05, 1975-10, 2010-01 DIN 6935:2011-10 4 1 Scope This standard applies for bent parts made of flat steel products for application in steel construction and mechanical engineering. For standards on flat steel products, see DIN EN 10025-2. 2 Normative refe

9、rences The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. DIN 250, Radii DIN EN 10025-2, Hot-rolled

10、products of structural steels Part 2: Technical delivery conditions for non-alloy structural steels 3 Bending radii 3.1 General When bending flat rolled steel such as sheets, strips, wide flats etc., the rolling direction shall be taken into consideration, since bending should be carried out transve

11、rse to the rolling direction, because this is more suitable for bending. The suitability of the rolled steel for bending shall be agreed with the manufacturers works when ordering. To guarantee bending suitability, the rolled surface shall be flawless and the sheared edges straight. For flat rolled

12、steel, the sheared edges on the outside of a bend shall also be de-burred at the bending location to prevent cracks from spreading from the cut edges. 3.2 Bending angle and thickness s The bending angle can have any value between 0 and 180. Thickness s decreases by approximately 20 % in the rounded

13、portion (see Figure 1). Key r Bending radius Bending angle Opening angle Figure 1 Bending radius (notation) To obtain uniform bends on bending rails, it is recommended that only bending radii from the series below be selected. The values printed in bold are to be preferred. DIN 6935:2011-10 5 Dimens

14、ions in millimetres r 1 1,2 1,6 2 2,5 3 4 5 6 8 10 12 16 20 25 28 32 36 40 45 50 63 80 100 These bending radii comply with the radii according to DIN 250. Table 1 gives the minimum permissible bending radii to be chosen for given sheet thicknesses and materials and for the applicable bending machine

15、s. The indicated values apply for bending angles 120. For bending angles 120 the next higher value in the table shall be used, e.g. if sheets of S 275 JR according to DIN EN 10025-2 are to be bent transverse to the rolling direction, with a thickness s = 6 mm, the minimum permissible bending radius

16、is r = 10 mm for 120 and r = 12 mm for 120. Table 1 Minimum permissible bending radius r Dimensions in millimetres Steel grades For bending transverse or parallel to the rolling direction Minimum permissible bending radius r for thicknesses s Up to Over Over Over Over Over Over Over Over Over Over O

17、ver Over Over Over 1 1 1,5 2,5 3 4 5 6 7 8 10 12 14 16 18 up to up to up to up to up to up to up to up to up to up to up to up to up to up to 1,5 2,5 3 4 5 6 7 8 10 12 14 16 18 20 S 235 JR S 235 J0 S 235 J2 Transverse 1 1,6 2,5 3 5 6 8 10 12 16 20 25 28 36 40 Parallel 1 1,6 2,5 3 6 8 10 12 16 20 25

18、28 32 40 45 S 275 JR S 275 J0 S 275 J2 Transverse 1,2 2 3 4 5 8 10 12 16 20 25 28 32 40 45 Parallel 1,2 2 3 4 6 10 12 16 20 25 32 36 40 45 50 S 355 JR S 355 J0 S 355 J2 Transverse 1,6 2,5 4 5 6 8 10 12 16 20 25 32 36 45 50 Parallel 1,6 2,5 4 5 8 10 12 16 20 25 32 36 40 50 63 Table 2 gives permissibl

19、e deviations for minimum bending radii which are to be expected for various sheet thicknesses and materials. Table 2 Permissible deviations for minimum bending radii r Dimensions in millimetres Steel grades Permissible deviations for minimum bending radii r for thicknesses s Up to 3 Over 3 up to 8 O

20、ver 8 up to 20 S 235 JR S 235 J0 S 235 J2 +0,5 +1 +1,5 0 0 0 S 275 JR S 275 J0 S 275 J2 +0,8 +1,5 +2 0 0 0 S 355 JR S 355 J0 S 355 J2 +1 +2 +3 0 0 0 DIN 6935:2011-10 6 4 Key to materials Table 3 provides examples of materials for which suitability for cold bending, cold flanging and cold curling is

21、guaranteed, taking into account the minimum permissible bending radii specified in Table 1. Table 3 Key to materials (examples) Type of steel Steel grade with a minimum tensile strength aOver 360 MPaup to 510 MPaOver 430 MPa up to 580 MPa Over 510 MPa up to 680 MPa Hot-rolled products of structural

22、steels according to DIN EN 10025-2 S 235 JR S 275 JR S 355 J2 aFor nominal thicknesses 5, Equation (3) is no longer valid so that k = 1 applies. DIN 6935:2011-10 9 Figure 7 Graphical representation of correction factor If only minimum requirements are set for the determination of cut lengths, rounde

23、d values as grouped together in Table 5 may be used for the correction factor k. Table 5 Correction factor k, rounded values Internal bending-radius r as a function of sheet thickness s Ratio r : s Over 0,65 Over 1 Over 1,5 Over 2,4 Over 3,8 up to 1 up to 1,5 up to 2,4 up to 3,8 Correction factor k

24、(rounded values) 0,6 0,7 0,8 0,9 1 For any value for , r and s, the corresponding compensating values can also be identified by the use of the correction factor k together with the graphical representations of factors in DIN 6935, Supplement 1. For calculated compensating values for several opening

25、and bending angles based on the above formula for correction factor k, see DIN 6935, Supplement 2. DIN 6935:2011-10 10 8 Representation and position of bend lines for developments The bend line indicates the middle of the bending radius and shall be represented by a thin continuous line. The positio

26、n of the bend line results from the abutting leg lengths a and b, with half of the positive or negative compensating value taken into account (see Figure 8). Figure 8 Representation and position of the bend line (notation) Developments shall only be explicitly drawn if the shape of the cut sheet is

27、not unambiguously determined by dimensioning and indication of the bend line. 9 Dimensioning and calculation of developed lengths (examples) All dimensions in millimetres EXAMPLE 1 Material: S 235 JR Sum of leg lengths 50 + 200 + 80 = 330 For = 90, r = 6, s = 4 then = 8,26 For = 90, r = 20, s = 4 th

28、en . = 13,44 = 21,7 Developed length . 308,3 309 Dimensions in millimetres Figure 9 Example 1 (notation) DIN 6935:2011-10 11 EXAMPLE 2 Material: S 235 JR Sum of leg length 50 + 170 + 246 + 50 = 516 For = 90, r = 20, s = 12 then . = 25,41 For = 45, r = 20, s = 12 then. = 6,12 For = 135, r = 32, s = 1

29、2 then = 7,25 = 38,78 Developed length . 477,22 478 Dimensions in millimetres Figure 10 Example 2 (notation) DIN 6935:2011-10 12 10 Development and marking of bend line position (example) Material: S 355 J2 All dimensions in millimetres Development: Sum of leg lengths 45 + 50 + 32 = 127 For = 45, r

30、= 10, s = 5 then . = 1,72 For = 135, r = 10, s = 5 then . = 3,00 = 4,72 Developed length . = 122,28 123 Dimensions in millimetres Figure 11 Development and marking of bend line position (example) (notation) Position of bend lines: For leg length = 45, = 45, r = 10, s = 5 and = 1,72 then 4414,4486,04

31、5272,145 = For leg length = 32, = 135, r = 10, s = 5 and = 3 then 315,305,1322332 = DIN 6935:2011-10 13 Bibliography DIN 1623, Cold rolled strip and sheet Technical delivery conditions General structural steels DIN 6935 Supplement 1, Cold bending of flat rolled steel Supplement 1: Factors determinin

32、g the correction value for calculating length of flats prior to bending DIN 6935 Supplement 2, Cold bending of flat steel products Supplement 2: Calculated compensating values DIN 59200, Flat products of steel Hot rolled wide flats Dimensions, mass, tolerances on dimensions, shape and mass DIN EN 10

33、048, Hot-rolled narrow steel strip Tolerances on dimensions and shape DIN EN 10058, Hot rolled flat steel bars for general purposes Dimensions and tolerances on shape and dimensions DIN EN 10131, Cold rolled uncoated and zinc or zinc-nickel electrolytically coated low carbon and high yield strength steel flat products for cold forming Tolerances on dimensions and shape DIN EN 10139, Cold rolled uncoated mild steel narrow strip for cold forming Technical delivery conditions DIN EN 10140, Cold rolled narrow steel strip Tolerances on dimensions and shape