DIN_2093_2006-03_e

DEUTSCHE NORMMarch 2006 D DIN 2093 Supersedes DIN 2093:1992-01 ICS 21.160 Disc springs – Quality specifications – Dimensions This copy will not be updated in case of changes! According to DIN reference sheet 3, reproduction of this copy is permitted only for intra-company purposes of SMS Demag AG. Tellerfedern – Qualitätsanforderungen – Maße Document comprises 18 pages Translation by DIN-Sprachendienst. In case of doubt, the German-language original should be consulted as the authoritative text. © No part of this translation may be reproduced without prior permission of DIN Deutsches Institut für Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany, has the exclusive right of sale for German Standards (DIN-Normen). English price group 12 www.din.de www.beuth.de !,vhÖ" 9836997 B or C based on the h0/t ratio. 1992-01 *) This English translation also includes amendments from Corrigendum DIN 2093:2006-03 Ber 1:2007-08. units and quantities have been aligned with the International System of Units (SI) as in ISO 31. b) Clause 4 now includes the assignment of springs to series A. 2 . 1978-04. σIII and σOM have been specified. c) In clause 7. 1967-04.DIN 2093:2006-03 Foreword This standard has been prepared by the Ausschuss Federn (Springs Standards Committee).*) Amendments This standard differs from DIN 2093:1992-01 as follows: a) Examples of designation for springs produced by turning (G) and for springs produced by fine blanking (F) are no longer included (see clause 4). Symbols. new values of Ft and of stresses σII. Previous editions DIN 2093: 1957-07. These are identified by a footnote. 1990-09. d) The standard has been editorially revised to take account of the new style rules for standards. only the edition cited applies. manufacturing process. T) 3 Terms and definitions Disc springs are annular coned elements that offer resistance to a compressive load applied axially. Quenched and tempered steels — Technical delivery conditions for boron steels DIN EN 10089. T) DIN EN ISO 6508-3.DIN 2093:2006-03 1 Scope This standard specifies requirements for the materials. C. For dated references. C. Metallic materials — Vickers hardness test — Part 2: Verification and calibration of testing machines DIN EN ISO 6507-3. D. F. E. N. DIN 2092:2006. F. All requirements specified here are minimum requirements. Metallic materials — Rockwell hardness test — Part 1: Test method (scales A. K. Metallic materials — Rockwell hardness test — Part 2: Verification and calibration of testing machines (scales A. They may be subjected to both static and fatigue loading. E. This standard covers three dimensional series of disc springs. C. Fasteners — Acceptance inspection DIN EN ISO 6507-1. B. N. D. Quenched and tempered steels — Technical delivery conditions for special steels DIN EN 10083-2. E. B. 3 . It includes graphs showing the permissible relaxation and the fatigue life of such springs. G. 2 Normative references The following reference documents are indispensable for the application of this document. H. either singly or in multiples. K. Metallic materials — Vickers hardness test — Part 4: Tables of hardness values DIN EN ISO 6508-1. Metallic materials — Rockwell hardness test — Part 3: Calibration of reference blocks (scales A. Disc springs — Calculation DIN 50969. T) DIN EN ISO 6508-2. Copper and copper alloys — Strip for springs and connectors DIN EN 10083-1. Cold-rolled narrow steel strip for heat treatment — Technical delivery conditions — Part 4: Spring steels and other applications DIN EN 10151. the latest edition of the referenced document (including any amendments) applies. They may be designed as single disc springs or as disc springs stacked in parallel or in series. K. For undated references. as a function of stress. Metallic materials — Vickers hardness test — Part 1: Test method DIN EN ISO 6507-2. G. and may have flat bearings. N. Hot-rolled steels for quenched and tempered springs — Technical delivery conditions DIN EN 10132-4. D. F. H. Stainless steel strip for springs — Technical delivery conditions DIN EN ISO 3269. Quenched and tempered steels — Technical delivery conditions for unalloyed quality steels DIN EN 10083-3. B. G. Metallic materials — Vickers hardness test — Part 3: Calibration of reference blocks DIN EN ISO 6507-4. Testing of high-strength steel building elements for resistance to hydrogen-induced brittle fracture and advice on the prevention of such fracture DIN EN 1654. H. dimensions and tolerances for disc springs. 30 . 4 Dimensional series h0/t A B C ∼ 0.75 ∼1. disc springs are divided into three groups and three dimensional series. which is a function of the material thickness. 2 or 3 (sectional view). including the relevant points of loading**) Designation of a disc spring of dimensional series A with an outer diameter. 4 4.40 ∼ 0.25 With flat bearings and reduced thickness No 2 1.3 Disc spring groups Group t 1 < 1.2 4. of 40 mm: Disc spring DIN 2093 — A 40 4. The assignment of disc springs to dimensional series is governed by the h0/t ratio.1 Dimensions and designation General a) without flat bearings: group 1 group 2 b) with flat bearings: group 3 Figure 1 — Single disc spring of group 1.DIN 2093:2006-03 In this standard. Classification into groups is based on the manufacturing process.25 ≤ t ≤ 6 No 3 > 6 < t ≤ 14 Yes Dimensional series **) See *) on page 2. De. F2. lt = l0 − 0. σ OM MPa MPa Poisson’s ratio Design stress Design stresses at the points designated II. σ III .DIN 2093:2006-03 5 Symbols. t t′ µ σ Initial cone height of springs without flat bearings. in the initial position Design length of springs stacked in series or in parallel. h′0 = l0 − t' l0 mm Number of disc springs or packets stacked in series Free overall height of spring in its initial position lt mm Test length of spring. units and descriptions Symbol Unit Description De mm Outer diameter of spring Di mm Inner diameter of spring D0 mm Diameter of centre of rotation E F Fc MPa N N Modulus of elasticity Spring load Design spring load when spring is in the flattened position Ft N ∆F L0 N mm Lc mm N Test load for length Lt or lt Relaxation Length of springs stacked in series or in parallel. OM (see Figure 1) σh MPa σO MPa Fatigue stress related to the deflection of springs subject to fatigue loading Maximum fatigue stress σU MPa Minimum fatigue stress σ H =σ O −σ U MPa Permanent range of fatigue stress R W i s1. III. F3… mm mm Thickness of single disc spring Reduced thickness of single disc spring with flat bearings (group 3) σ II. s3 . in the flattened position Number of cycles to failure Spring rate Energy capacity of spring h0 N/mm N mm mm h0′ mm Initial cone height of springs with flat bearings.V′ Theoretical centre of rotation of disc spring cross section (see Figure1) Lever arms Ra Mean surface roughness P 5 . h0 = l0 − t V..75 h0 s mm mm Deflection of single disc spring Spring deflections related to spring loads F1.. s2 . 3 0.5 31 2.9 6 500 7 716 11 976 11 388 15 025 2.3 18.37 1.27 3. stainless steel for springs in accordance with DIN EN 10151.6 3.2 8.25 1.2 10.32 3.75 1 1.56 0. E = 206 000 MPa. of 206 000 MPa.2 6.4 0.5 0.4 1. DIN EN 10089 or DIN EN 10132-4.5 1.6 0.8 1. The values given for F and σ in Tables 1 to 3 then cease to apply.4 25.2 7.5 2.47 2.87 1 332 1 453 1 295 1 418 1 239 1 326 1 284c 1 338 −1 594 −1 679 −1 558 −1 663 −1 505 −1 708 −1 675 −1 753 71 80 90 100 112 125 140 160 36 41 46 51 57 64 72 82 5.1 4.g.1 1.7 0.21 1.2 12. 0 ≈ 0.35 0.4 28. design values 7.1 1.5 6.5) 10 (9.99 1.55 1.2 1 301 1 295 1 290 1 296 1 419 1 274 1 296 1 332 −1 555 −1 558 −1 560 −1 534 −1 562 −1 562 −1 570 −1 611 40 45 50 56 63 20. E.2 3.1 210 325 660 797 16 18 20 22.45 0.65 8.3 4. Carbon steel shall only be used for the manufacture of group 1 springs (see also Table 4).2 13.5 35.2 0.42 5.7 7 8.2 14.4.75 3.7 2 2.8 1 013 1 254 1 521 1 929 2 926 2 841 3 871 5 187 0.8 10.1 1.2 9. In such cases it is recommended to consult the spring manufacturer.5 4.5 3 3 3.62 8.75 2 0.3 1.7 0.25 0.2 0.1 Dimensional series A Disc springs with De h ≈ 18.5 .DIN 2093:2006-03 6 Spring material Springs complying with this standard shall be made from steel as specified in DIN EN 10083.5 14 4.64 1.5 1.65 0.5 8.15 2.5 25 28 31. NOTE The design of disc springs made from steel as above shall be based on a modulus of elasticity.5 10.25 1.9 1 1.8 0.5) 8 (7. µ = 0.6 6.75 h0 0.2 16. The modulus of elasticity and strength property of other materials (e. copper alloys (spring bronze) in accordance with DIN EN 1654) will likely be different.4 3.9 1 1.6 11.5 0. nominal sizes.3 0.3 0.45 0.05 2. 7 Spring dimensions.2 5.15 3.85 1 328 1 296 1 418 1 274 1 296 −1 595 −1 534 −1 659 −1 565 −1 524 4 5 5 6 6 8 (7.2 2.92 2.4) 1.3 t t Table 1 Group 1 2 3 6 De Di h12 H12 t or (t′)a h0 l0 Ft lt σIIIb σOM s ≈ 0.5 0.5 20 535 33 559 31 354 48 022 43 707 85 926 85 251 138 331 4.4 5.4 22.66 1.4 0.2 11.55 0.87 1 218 1 218 1 382 1 308 −1 605 −1 595 −1 666 −1 551 s = h0 8 10 12.75 2.45 2.77 0.25 2.55 6.6 1. 15 1.4 25.5 5.5 40 45 50 9.3 0. and in the case of dimensional series C.2 Dimensional series B Disc springs with De h ≈ 28.82 0.27 1 049 1 090 1 149 1 101 1 109 1 035 −1 235 −1 284 −1 415 −1 293 −1 333 −1 192 1 2 100 112 125 140 160 180 6.1) 4.1 7 .5 9 10.8 0.2 3.5 1.2 6.8 5.DIN 2093:2006-03 Table 1 (concluded) Group 3 De Di h12 H12 180 92 200 225 250 102 112 127 t or (t′)a h0 l0 lt Ft σIIIb s ≈ 0.2 8. c The values specified apply for the largest calculated tensile stress at the point designated III.3 6 4 438 7 189 6 725 10 518 14 161 2.7 0. t.1 13 070 17 752 29 908 27 920 41 008 37 502 4.8 0.57 4. 7.9 1 1.55 0.4 1.6 4.35 1.4 0.2 10.4 566 748 707 862 1 107 1 913 1 699 2 622 3 646 4 762 0.3 1.79 2.8 2.5 31 36 41 46 2 2.85 0.3 18.71 1 312 1 281 1 114 1 101 1 109 s = h0 −1 505 −1 531 −1 388 −1 293 −1 333 8 10 12.75 h0 σOM s = h0 10 (9.25 0.3 20.25 2.2 7.4 0.4) 4 14 125 417 11 1 201c 12 (11.7 0.5 14 16 4.35 1 114 1 118 1 079 1 023 1 086 1 187 1 073 1 136 1 144 1 140 −1 363 −1 386 −1 276 −1 238 −1 282 −1 442 −1 258 −1 359 −1 396 −1 408 56 63 71 80 90 28.65 0.2 16.15 2.07 1.25 1.5 25 28 31.9 1.6 0. which then gives the value t′.6 1.4 2.6 1.3 2. 0 ≈ 0.4 0.96 1.2 0.2 17 19.2 12.2 5.2 14.75.25) 12 (11.36 0.12 7.87 6 7.94 3 3.65 3.47 0.5 3 3.59 0.3 7.25 1.5 2.5 3.75 2 2. In the case of dimensional series A and B.6 0.4 22.6 16.07 2.5 11.6 183 020 171 016 248 828 13.45 0.35 0. b The values specified apply for the largest calculated tensile stress on the lower edges of the spring. F (where s ≈ 0.3 t t Table 2 Group De Di h12 H12 t or (t′)a h0 l0 Ft lt σIII σOM s ≈ 0.25 15.2 11. the desired spring load.4 1 227 1 137c 1 221c −1 576 −1 611 −1 489 −1 596 a The values specified for t are nominal values.45 1.3 0. In the case of springs with flat bearings (cf.47 1.5 0.2 5 5.5 1.5 1.25) 14 (13.5 0. E = 206 000 MPa.05 3.12 1 092 1 088 1 055 1 142 1 114 −1 284 −1 360 −1 246 −1 363 −1 363 51 57 64 72 82 92 3.05 118 209 294 279 410 18 20 22.5 4 4.55 0.94 0.75 h0 0.2 1. t′ ≈ 0.75 h0).5 5.75 2 0.2 4.25 4.8 3.7 0.05 13. t′ ≈ 0.2 8.8 0.94 × t. group 3 in clause 4).9 1 1.5 35.5 4 5 5 6 6 2.2 1. µ = 0. is to be obtained by reducing the thickness of single disc springs.5 0.96 × t. 65 1.96 × t.3 20.1 7.3 Dimensional series C Disc springs with De h ≈ 40.9 8 6 613 7 684 8 609 10 489 15 416 2. the desired spring load.45 0.4 1.35 2.5 2.2 0.6 1.5 3.6 1.3 0.5 2.8 0. group 3 in clause 4).65 1.5 25 28 31. In the case of disc springs with flat bearings (cf.85 2.3 3.2 9.95 2.9 1.9 1 1.6 14. and in the case of dimensional series C.97 4.5 (6.5 1. t′ ≈ 0.3 18.7 9.8 5.25 8.3 t t Table 3 Group 1 2 3 De Di h12 H12 t or (t′)a h0 l0 Ft lt σIII σOM s ≈ 0.75 σIII σOM 1 254 1 176 1 244 s = h0 −1 409 −1 267 −1 406 a The values specified for t are nominal values.2 12.2 8.62 11.4 25.06 1.8 1.6 254 426 600 801 687 832 1 017 1 891 1 550 2 622 4 238 5 144 0.99 3.2 5. F (where s ≈ 0.96 × t.45 0. F (where s ≈ 0.7 6.85 3. and in the case of dimensional series C.46 0.5 7 13.6 6.5 13.65 0.65 1 063 1 227 1 259 1 304 1 130 1 078 1 063 1 253 1 035 1 218 1 351 1 342 −1 024 −1 178 −1 238 −1 282 −1 077 −1 042 −1 024 −1 227 −1 006 −1 174 −1 315 −1 295 80 90 100 112 125 41 46 51 57 64 2.32 1.2 5.46 0.8 0.94 × t.32 0.2 7.26 0.75 h0). In the case of disc springs with flat bearings (cf. 8 .2 3. group 3 in clause 4).8 17 195 21 843 26 442 36 111 44 580 50 466 5.6 1.5) 8 (7.2 6.3 2.75 h0 9. is to be obtained by reducing the thickness of single disc springs.3 4.94 × t.85 2. 0 ≈ 1. E = 206 000 MPa.7 6.25 0.5 6.25 1.55 0. In the case of dimensional series A and B.4 28.25 0.92 1. the desired spring load.45 0.02 5.25 2.7 0.5 35.8 0.8 8.4 9.05 39 58 151 123 154 214 20 22.8 0.2 6. µ = 0.05 1. 7.15 4. t′ ≈ 0.15 1.2 7 7.5 14 16 18 4.95 1 249 1 238 1 201 1 247 1 137 1 116 −1 203 −1 189 −1 159 −1 213 −1 119 −1 086 a The values specified for t are nominal values.5 31 36 0.95 3.3.6 14.9 11 12. is to be obtained by reducing the thickness of single disc springs.4) h0 l0 5. which then gives the value t′.35 0. t.9 4.35 7.5 17 Ft lt 76 378 70 749 119 050 s ≈ 0.75 h0 0. t.5 5.2 14.25 1.6 6.45 4. which then gives the value t′.6 0.19 1.05 1.39 2.57 3.5 40 45 50 56 63 71 10.52 0.8 4.35 0.4 0.66 0.27 8.2 0.6 1 034 965 1 278 1 055 1 009 1 106 s = h0 −1 003 − 957 −1 250 −1 018 − 988 −1 052 8 10 12.15 1.8 0.45 0.2 11.05 2.6 1. In the case of dimensional series A and B.9 5.3 1. t′ ≈ 0.8 0.7 3 3.9 1 1.5) 10 (9.5 0.5 0.2 16.DIN 2093:2006-03 Table 2 (concluded) Group 3 De Di h12 H12 200 225 250 102 112 127 t or (t′)a 8 (7.4 22. t′ ≈ 0.62 1 370 1 286 1 235 1 218 1 318 −1 311 −1 246 −1 191 −1 174 −1 273 140 160 180 200 225 250 72 82 92 102 112 127 3.75 h0).7) 4.2) 7 (6.99 2.8 2 0.6 0. 5 Ra < 12. De and Di turning. edge rounding or stampingb. 8.2 Ra < 12. edge rounding or fine blankingc. b Stamping without D and D turning is not permitted.1 Manufacturing process and surface quality Disc springs shall be manufactured as specified in Table 4.5 DIN EN 10132-4 Ra < 12.DIN 2093:2006-03 8 Manufacture 8.3 Ra < 6. in µm surfaces. turning on all sides. After heat treatment.5 DIN EN 10083 DIN EN 10089 Ra < 12.2 DIN EN 10132-4 Ra < 12. De and Di turning. the disc spring shall not exhibit a depth of decarburization exceeding 3 % of its thickness. the hardness of disc springs shall lie within the range of 42 HRC to 52 HRC. edge rounding or fine blankingc.5 DIN EN 10132-4 Ra < 6.3 DIN EN 10132-4 Ra < 6. 75 %. cold forming.5 DIN EN 10132-4 a The values specified do not apply to shot peened springs. cold forming. e i c Fine blanking in accordance with VDI Richtlinie (VDI Guideline) 2906 Part 5: Clean cut min. 25 %.2 Heat treatment To ensure satisfactory fatigue life with minimum relaxation. For group 1 disc springs.5 Ra < 12.3 Ra < 3.5 Ra < 12. cold forming. cold forming. Table 4 — Prescribed manufacturing processes and surface quality Group Manufacturing process 1 Stamping. 9 . edge rounding 3 Surface roughnessa Surface roughness on on upper and bottom outer and inner edges. in µm Cold or hot forming. tear off max. scar category 2. cold forming. edge rounding 2 Stampingb. the hardness shall be determined according to Vickers (425 HV10 to 510 HV10). edge rounding Material as in Ra < 3. black finishing. 9 9.8 < t ≤ 6.10 . Disc springs with a hardness exceeding 40 HRC are more prone to the risk of hydrogen embrittlement than softer springs.0**) + 0.15 6.4 Presetting After heat treatment.DIN 2093:2006-03 8.06 0. Whether and which corrosion protection is to be provided shall be a function of the particular spring application. Phosphating and oiling is the standard corrosion protection for disc springs. After loading the disc spring with twice of its test load Ft. For disc springs with dynamic loading galvanic surface protection should be avoided. When ordering disc springs with galvanic surface protection it is advisable to consult the spring manufacturer.1 Tolerances Tolerances on diameter De: tolerance class h12 Coaxiality tolerance for De ≤ 50: 2 × IT11 Coaxiality tolerance for De > 50: 2 × IT12 Di: tolerance class H12 9. DIN 50969).5 Surface treatment and corrosion protection The surface shall be free from defects such as scars. the tolerances for the spring load as specified in Table 7**) shall be met. heat treatment and surface treatment (cf.2 Tolerances on thickness Table 5 Group 1 2 3 **) See *) on page 2. and the application of protective metallic coatings such as zinc or nickel. shot peening is recommended.6 + 0.25 ≤ t ≤ 3. Suitable corrosion protections include phosphating. cracks and corrosion. 8.3 Shot peening In order to increase the values given in Figures 5 to 7. each disc spring shall be loaded until it is in the flat position. 8. 10 t Tolerances 0.03 − 0.8 + 0. Galvanizing processes using aqueous solutions that are currently available may not preclude the risk of hydrogen embrittlement. This shall be agreed between customer and manufacturer.09 1.6 < t < 1.12 3.0 < t ≤ 14. This procedure shall be the subject of agreement between customer and manufacturer.2 ≤ t ≤ 0.04 − 0.02 − 0. Particular care shall therefore be taken when selecting the material. manufacturing process.05 − 0.0 ± 0.25 + 0. 05 1.3 Tolerances on free overall height.0 < t ≤ 6.DIN 2093:2006-03 9. % 1 t < 1.08 2.75 h0.0 + 15 − 7.4 9.0 < t ≤ 14.25 ≤ t ≤ 3.30 − 0.4.0 ± 0.0 < t ≤ 6.15 − 0. The flat plates shall be hardened.0 + 0.0 ±5 To comply with the specified load tolerances. ground.5 2 3 3.5 1. using a suitable lubricant. l0 Table 6 Group t Tolerances 1 t < 1.25 + 25 − 7.15 6.4.2 Springs stacked in series Figure 2 — Loading and unloading curves obtained from testing springs stacked in series 11 .0 + 0.20 − 0.0 + 10 − 5 6.30 2 3 9.25 ≤ t ≤ 2. Table 7 Group t Tolerances for Ft at lt = l0 − 0. and polished.10 3. 9.25 + 0.0 < t ≤ 3.75 h0. The measurement is taken while loading between flat plates. it may be necessary to exceed the tolerance values specified for l0 and t.0 + 0.10 − 0.0 < t ≤ 14.1 Tolerances on spring load Single disc springs The spring load Ft shall be determined at test length lt = l0 − 0. when subjected to a constant load. For disc springs under static load.0 1. Ft. This should be preferably a mandrel. The clearance between disc springs and mandrel shall be as specified in Table 9. 12 . Table 9 — Recommended clearance between disc spring and guiding element Di or De Over 16 Over 20 Over 26 Over 31. Creep is defined as the further decrease in length of the disc spring with time. the spring load determined for the unloading curve shall make up at least the minimum percentages specified in Table 8 of the spring load determined for the loading curve (see also Figure 2). Depending on the application. Relaxation is defined as the decrease in load with time.DIN 2093:2006-03 Ten single disc springs stacked in series shall be used to determine the deviation in load between the loading curve and the unloading curve. Table 8 — Minimum spring load at unloading.5 90 Clearance between disc spring and guiding element A guiding element is necessary to keep the disc spring in position.5 0. a sleeve is preferred. The flat plates shall meet the requirements specified in 9.6 0. At Lt = L0 − 7.8 1.4.5 h0. when the disc spring is compressed to a constant length.5 Over 50 Over 80 Over 140 Up to 16 up to 20 up to 26 up to 31. ∆l. as a percentage of the spring load at loading at Lt Group A 1 2 3 9. Its influence can be estimated on the basis of the design stress σOM (see DIN 2092. Prior to testing.6 10 Creep and relaxation All disc springs lose load during usage.4 0. The individual disc springs shall be centred by a mandrel in compliance with clause 13. the guideline values for relaxation illustrated in Figures 3 and 4 should not be exceeded. Both creep and relaxation are largely a result of the stress distribution over the cross section of the disc spring.5 Dimensional series B 90 92. the disc spring shall be compressed to twice its test load. In the case of external positioning. clause 10).5 95 C 85 87.1.2 0. ∆F. this is expressed by creep or relaxation.5 up to 50 up to 80 up to 140 up to 250 Total clearance 0.3 0. DIN 2093:2006-03 Figure 3 — Permissible relaxation for disc springs made of carbon steel in accordance with DIN EN 10132-4 13 . 11 Permissible stresses 11.20 h0 in order to avoid cracking at the upper inner edge. the design stress.1 Static and rarely alternating loading For disc springs made of steels according to DIN EN 10089 or DIN EN 10132-4. point I (see Figure 1) as a result of residual stresses from the presetting process.2 Dynamic loading Minimum initial deflection to avoid cracking: Disc springs subject to fatigue loading shall be designed and installed in such a way that the initial deflection is s1 ≈ 0. at maximum deflection shall not exceed 1 600 MPa. σOM.DIN 2093:2006-03 Figure 4 — Permissible relaxation for disc springs made of alloy steel in accordance with DIN EN 10089 and DIN EN 10132-4 If the ambient temperature exceeds 100 °C. the spring manufacturer should be consulted. 14 . Higher stresses may cause a higher loss of spring load (see clause 10). 11. which are subject to static loading or to moderate fatigue conditions.15 h0 to s1 ≈ 0. at three different numbers of stress cycles.25 mm 15 . σU. disc springs preloaded from s1 ≈ 0. The information given in Figures 5 to 7 represents the results of laboratory testing using fatigue testing equipment capable of producing sinusoidal loading cycles and the statistical results obtained for a 99 % probability of fatigue life.1 Permissible loading Figures 5 to 7 illustrate the fatigue life of disc springs subject to dynamic loading that have not been shot peened. Figure 5 — Fatigue life of not shot peened disc springs with t < 1. The figures are valid for single disc springs and stacks with I ≤ 10 disc springs stacked in series.2. To ensure the expected fatigue life of disc springs. N.15 h0 to s1 ≈ 0. and N = 5 × 105. as a function of the minimum stress. They specify guideline values for the permanent range of stress. Test conditions are: room temperature. namely where N ≤ 2 × 106.DIN 2093:2006-03 11. they shall be protected from mechanical damage and other adverse conditions. N = 105. σH. Intermediate values for other numbers of stress cycles may be estimated based on this information.20 h0. surface hardened and perfectly processed inner and outer guidance. shock loads and resonance) will shorten the fatigue life. In this case the values given in the above figures shall be converted by appropriate factors of safety.g.DIN 2093:2006-03 Figure 6 — Fatigue life of not shot peened disc springs with 1. the spring manufacturer should be consulted where necessary.25 mm ≤ t ≤ 6 mm Figure 7 — Fatigue life of not shot peened disc springs with 6 mm < t ≤ 14 mm It should be noted that stress cycles in practice are generally not sinusoidal in form. sudden dynamic loading. Any additional type of loads (e. 16 . 12 Testing Determination of the properties covered in 12. It shall be permitted to use unhardened guiding elements where the disc spring is subject to static loading. In the case of stacks with a highly degressive load/deflection curve (dimensional series C) and a large number of single disc springs stacked in series. Disc springs at the moving end of the stack deflect more than the others.1 and 12. De Inner diameter. 13 Other relevant requirements Where possible. The indentation shall be made on the upper surface of the disc spring.8 mm. an uneven deflection of the single disc springs can be expected. for other arrangements of stacks of springs. although some relevant information is usually obtainable from the spring manufacturer. This will result in a shorter fatigue life than shown in Figures 5 to 7.75 h0) Outer diameter. Table 10 Spring characteristics AQL value Major characteristics Spring load. 12. 17 .DIN 2093:2006-03 NOTE Reliable information regarding the fatigue life is not available for disc springs made from materials other than those specified here. The surface of the guiding element should be smooth and perfectly finished. and Rockwell hardness testing according to DIN EN ISO 6508-1 to DIN EN ISO 6508-3. for disc springs consisting of more than ten single disc springs stacked in series.2 shall be the subject of agreement between customer and manufacturer. l0 Spring thickness. Di Minor characteristics Free overall height in initial position. The fatigue life of disc springs can be prolonged considerably by additional shot peening. t or t' Surface roughness. F (where s ≈ 0. the guiding element and the support plate shall be made from case-hardened materials. Ra 1 1. nor for springs subjected to chemical or thermal effects. at a point that lies centrally between the inner and outer edges. and have a minimum hardness of 60 HRC.5 12.2 Hardness testing Vickers hardness testing shall be carried out according to DIN EN ISO 6507-1 to DIN EN ISO 6507-4.1 Check of dimensions and other spring characteristics The specifications given in DIN EN ISO 3269 shall be applied in addition to the characteristics and quality levels specified in Table 10. with a case depth of ≈ 0. This effect is caused by friction between the disc springs and the guiding element and dimensional tolerances. Cold rolled narrow steel strip — Tolerances on dimensions and shape DIN EN 12476. Hot-rolled narrow steel strip — Tolerances on dimensions and shape DIN EN 10051. Hot rolled wide steel flats — Dimensions. mass and tolerances DIN EN 10048. Tabular layouts of article characteristics for springs DIN 59200. Preparation of steel substrates before application of paints and related products — Specifications for metallic blast-cleaning abrasives — Part 1: General introduction and classification DIN ISO 2162-1.DIN 2093:2006-03 Bibliography DIN 4000-11. Continuously hot-rolled uncoated plate. Technical products documentation — Springs — Part 1: Simplified representation DIN ISO 2162-3. sheet and strip of non-alloy and alloy steels — Tolerances of dimensions and shape DIN EN 10140. Phosphate conversion coatings of metals — Method of specifying requirements DIN EN ISO 11124-1. Technical product documentation — Springs — Part 3: Vocabulary 18 .