Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 12511-2 (2004): Springs - Disc Spring, Part 2:Specification [TED 21: Spring]

IS 12511 (Part 2) :2004

HIhi-am tilwmftm2faR1-R

( WRi7 jpi%wl )

Indian Standard

SPRINGS — DISC SPRINGPART 2 SPECIFICATION

(First Revision)

ICS21.160

0 BIS 2004

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

August 2004 Price Group 6

Automotive Springs and Suspension Systems .Sectional Committee, TED21- .-.

FORE WORD

This Indian Standard (Part 2) (First Revision) was adopted by the Bureau of Indian Standards, after the draftfinalized by the Automotive Springs and Suspension Systems Sectional Committee had been approved by theTransport Engineering Division Council.

The dimensions specified in this standard are intended to provide a framework for the preferred types of discsprings to be used. From the comparative y small number of types, it is possible to assemble a variety of combinationsproducing spring columns with wide variety of spring characteristics. Attempts to increase the range of discsprings conforming to this standard, for example, by inserting more closely graded standard sizes, cannot berecommended. The user should endeavour, as far as possible, to use only disc spring sizes specified in this standard.Other designs of disc springs differing ‘from the dimensions specified in this standard constitute special orders.The works standards of the manufacturers will, however, continue to be available for such special orders.

The specified disc springs may be statically loaded up tos = 0.75 h without any risk of setting effects. When discsprings are subjected to fatigue loading, the fatigue fracture always starts on the underside of the disc. The bgreater of the theoretical tensile stresses in each case fors = 0.75 hOat location-H or 111,respectively of the dischas been specified for each spring. The calculation has been based on Part 1 of this standard, the influence of theseating faces and, for Group 3 springs of the reduced disc thicknesses.

.ln order to differentiate these disc springs from other compression elements which are outwardly similar, thisstandard also contains quality specifications. Certain minimum requirements for disc springs are indispensablein order to achieve good fatigue strength values. It is recommended to adopt those minimum requirements alsofor non-standardized disc springs.

The revision of this standard was undertaken so as to align it with the base standard which is being revised. Thefollowing are the technical changes incorporated:

a)

b)

c)

d)

e)

f)

g)h)

j)k)

m)

n)

Grouping/classification as per thickness of the single disc.

Spring force, Fin base standard which has been increased (see Tables 2, 3 and 4).

Requirement of compressive load in spring single disc has been added (see 9).

Tensile load of spring disc has been changed in all categories and groups.

Tolerances in 8 is included.

Tolerances in 8.1 have been changed for thickness of disc. Moreover it has been.further grouped in asper the classification.

Tolerance in overall height (see 8.3) has been changed and has been relaxed considerably.

Tolerance on permissible deviation in spring force F for disc springs is given. The graph and testmethod to find it is provided.

Prestress load and relaxations are also suggested with respect to the various raw material classes.

A clause on testing is also introduced.

Moderate fatigue condition (see 12) and development of various stresses in spring subjected to fatigueloading are included.

Requirement of surface roughness number has been added (see 15.1).

In the preparation of this standard, considerable assistance has been derived from “DIN2093-1992 ‘Dimensionsand quality of conical disc springs’ issued by Deutsches Institut fur D Normung (DIN).

The composition of the Committee responsible for the preparation of this standard is given at Annex A.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance withIS 2: 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained inthe rounded off value should be the same as that of the specified value in this standard.

IS 12511 (Part 2) :2004

Indian Standard

SPRINGS — DISC SPRINGPART 2 SPECIFICATION

(First Revision)

1 SCOPE

1.1 This standard (Part 2) specifies requirements forthe materials, dimensions, tolerances, and permissiblestresses for conical disc springs. It includes graphsshowing the permissible relaxation and the endurancelife of such springs, as a function of stress.

1.2 The values specified in this standard apply tooperating temperatures between Oand 60”C.

1.3 The minimum requirements specified are intendedto ensure the proper performance of conical discsprings and may also be applied to non-standardizedsprings.

1.4 The three series specified here represent groups ofspring sizes which have met with general acceptancein practice.

2 REFERENCES

The following standards contain provisions whichthrough reference in this text, constitute provision ofthis standard. At the time of publication, the editionsindicated were valid. All standards are subject torevision and parties to agreements based on thisstandard are encouraged to investigate the possibilityof applying the most recent editions of the standards—indicated below:

IS No.

1586:2000

2507:1975

12511(Part 1): 2004

7001:1989

Title

Method for Rockwell hardness testfor metallic material (scales A-B-C-D-E-F-G-H-K 15N, 30N, 45N, 15T,30T and 45T) (third revision)

Specification for cold rolled steelstrips for springs (first revision)

Springs-Disc spring: Part 1Designand calculation (under print)

Springs — Shot peening of steelparts — Specification (f2rst revision)

3 CONCEPT

Disc springs are annular coned elements that offerresistance to a compressive force applied axially. Theymay be designed as single discs or as discs stacked in

parallelor in series, either singly or in multiples. Theymay be subjected to both static and fatigue ‘loading,and may have ground end surfaces.

4 SYMBOLS

The following symbols and units shall apply (seeFig. 1):

D,

Di

E

F

hO

10

s

t

t’

CJ

ah

%

G0

‘H

(Go-

‘OM

LO

Outside diameter

Inside diameter

Modulus of elasticity

Spring force of single disc

Operand (theoretical spring travel)down to the completely flat position10–t

Overall height of unloaded single disc

Unit

mm

mm

N/mm2

N

mm

mm

Spring travel of single disc (deflection) mm

Thickness of single disc

Reduced thickness of single disc in the mmcase of disc springs with seating faces(Group 3)

Theoretical stress N/mmz

Mean fatigue stress associated with N/mmzthe deflection of springs subject tofatigue loading

Minimum fatigue stress N/mm2

Maximum fatigue stress N/mm2

Range of stress N/mmz

5“ )

Design stresses at the points N/mm2designated OM I, II, 111and IV(see Fig. 1)

Length of springs stacked in series or mmin parallel, in the initial position

5 CLASSIFICATION

This standard makes a distinction among three_groupsof springs, in accordance with Table 1.

1

IS 12511 (Part 2) :2004

Conical disc spring of group f or 2

Conical disc spring of group 3D,

F =-4

+

m

Jlis

FIG. 1 CROSS SECTION OF A SINGLE DISC,INCLUDINGTHE RELEVANT POINTS OF LOADING

Tabte 1 Groups of Springs

(Clause 5)

S1No. Group Thickness of Single Disc Single Disc with Ground Endst

(1) (2) (3) (4)

i) 1 Less than 1.25 Noii) 2 From 1.25 to 6 No

iii) 3 Over 6 up to 14 Yes

2

IS 12511 (Part 2) :2004

6 DIMENSIONS

The dimensions shall be as given in Tables 2,3 and 4.

Table 2 Conical Disc Springs of Series A (with ~ = 18; } = 0.4,E=206000 N/mm2, and w = 0.3)

(F’orewor~ and Clause 6)

Group De Di1or (t-’)’)

ho [0 F s I.-s @OM2)=1,3)

‘%1

h12 H,2

(I) (2) (3) (4) (5) (6)

N(where

s x 0.75 hO)

(7) (8) (9)

N/mm2 N/mm2

(10) (11)

81012,51416

.1 1820

22.5252831.535.54045

2 505663718090

100112

1253 140

16018020022s250

4.25.26.27.28.29.2

10.2

11.212.214.216.318.320.422.425.428.5313641465157

64728292

102112127

0.40.50,70.80.91.1.1

1.251.51.51.7522.252.5333.545566

8(7.5)8(7.5)

10(9.4)10(9.4)12(11.25)12(11.25)14(13.1)

0.20.250.30.30.350.40.45

0.50.550.650.70.80.911.11.31.41.61.722.22.5

2.63.23.544.255.6

0.60.7511.11.251.41.55

1.752.052.152.452.83.153.54.14.34.95.66.778.28.5

10.611.213.51416.21719.6

210329673813

100012501530

1950291028503900519065407720

1200011400150002050033700314004800043800

8590085300

139000125000183000171000249000

0.150.190.230.230.260.30.34

0.380.4 I0.490.530.60.680.750.830.981.051.21.281.51.651.88

1,952.42,6333,153.754,2

0.450.560.770.870.991.11.21

1.371.641.661.922.22.472.753.273.323.854.45.425.56.556.62

8.658.8

10.871113.0513.2515.4

-1 200-1210-1280-1190-1160-1170-1180

-1170-1210-1180-1190-1210-1210-I 150-1250-1180-1140-1200-1260-1170-1250-1130

-1280-1260-1320-1180-1210-1120-1200

1220’1 240*1 420*1 340*1 290*1300”“1300*

1320”1 410*1 280*1 31O*1 330*1340”1 300*1430”1 280*1300”1 330*1 460*1 300*I 420”1240”

1330”1 280*1 340*12001‘230*11401220

‘) The values specified fort are nominal values. In the case of Group 3-springs, the values given in parentheses apply fort’ (reducedthickness). Limit deviations for thickness are specified in 8.2.

2J Design (compressive) stresses at the point designated OM, that is on the conical surface of the spring.

1’ The values specified apply for the largest tensile stresses on the lower edges of the spring. The values specified with an asterisk (*)apply to the point designated II, those without an asterisk. to the point designated 111.

NOTE — In the case of springs with ground ends (see Group 3 in 5), the desired spring l~ad, F (where s is equal to approximately0.75 )1,), is to be obtained by reducing the thickness of single discs, t, which then gives the value r’. In the case of spring series A andB, t shall be equal to approximately 0.94 t, and in the case of spring series C, it shall be equal to approximately 0.96 t.

3

IS 125.11 (Part 2) :2004

.

Table 3 Conical Disc Springs of Series B (with ~ = 28; ~ = 0.75,E=206000 N/mm2, and j.I= 0.3)

(Foreword and Clause 6)

Group De D, ho l,, F/or (t-])’) s 10-s ~ ~M2) ~,,J)

%1

h 12 H,, N(where

S = 0.75 h,,)N/mm2 N/mmz

(1) (2) (3) (4) (5) (6) (7) (8) (9) (lo) (11)

81012.5“1416

1 182022.52528

31.535.54045505663

2 718090

100112125140160180

200

3225250

4.25.26.2.7.28.29.2

10.211.212.214.2

16.318.320.422.425.428.531364146515764728292

I02112127

0,30.40.50.50.60.70.80.80.91

1.251.251.5I .75222.52.533.53.545566

8(7.5)8(7.5)

10(94)

0.250.30.350.40.450.50.550.650.70.8

0.911.151.3I.41.61.752.32.52.83.23.544.55.1

5.66.57

0.550.70.850.91,05I ,21.351.451.61,8

2.152.252.653,053.43.64.254,55.366.37.28.59

10,511.1

13.614.517

119213291279412572745710868

1110

19201700262036604760444071806730

1050014200131001780030000279004110037500

7640070800

119000

0.190.230.260.30.340.380.410.490.530.6

0.680.750.860.981.051.21,311.51.731.882.12.42.6333.383.83

4.24.885.25

0.360.470.590.60.710.820.940.961.071.2

1.47I .51.792.072.352.42.9433.574.124.24.85.8767.127.27

9.49.62

11.75

-1140-1170-1000-970-1010-1040-1030-962-938-961

-1090-944-1020-1050-1060-963-.1020-934-1030-1030-925-963-1060-970- I 000-895

-1060-951-1050

13301300111011001 120I 1301110108010301090

119010701130I 15011401090109010601 1401120105010901150111011101040

125011801240

‘) The values specified for I are nominal values. In the case of Group 3 springs, the values given in parentheses apply fort (reducedthickness). Limit deviations for thickness are specified in 8.2.

2, Design (compressive) stresses at the point designated O&f,that is on the conical surface of the spring.

‘) The values specified apply for the largest tensile stresses on the lower edges of the spring. The values specified with an asterisk (*)apply to the point designated II, those without an asterisk, to the point designated III.

NOTE — In the case of springs with ground ends (see Group 3 in 5), the desired spring load, F (wheres is equal to approximately0.75 h,), is to be obtained by reducing the thickness of single discs, t,which then gives the value (’. In the case of spring series Aand B, t’ shall be equal to approximately 0.94 t, and in the case of spring series C, it shall be equal to approximately 0.96 t.

4

IS 12511 (Part 2) :2004

Table 4 Conical Disc Springs o“fSeries C (with ‘~ = 40; } = 1.3, E = 206000 N/mmz, and p = 0.3)

(Forewordj and Clause 6)

Group D, Di t or (r-’)’) ho 10 F s 10-s J)rJWr2) allcrln

N(where

s z ().75 hO) N/mm2 N/mm2

(1) (2) (3) (4) (5) (6) (7) (8) (9) (lo) (11)

81012.5141618

12022.5252831.535.540

455056637180

290

100112125140160180200

2253 250

4.25.26.27.28.29.2

10.211.212.214.216.318.320.4

22.425.428.531364146515764728292

102

112127

0.20.250.350.350.40.450.50.60.70.80.80.91

1.25.1.251.51.822.252.52.733.53.84.34.85.5

6.5(6.2j7 (6.7)

0.250.30.450.450.50.60.650.80.911.051.151.3

1.61.61.952.352.62.953.23:53.94.54.95.66.27

7.17.8

0.450.550.80.80.91.051.15I .41.61.81,852.05“2.3

2.852.853.454.154,65.25.76.26.988.79.9

1112.5

13.614.8

3958

152123155214254425601801687831

1020

18901550262042405140661076808610

10 Soo1540017200218002640036100

4460050500

0.190.230.340.340.380.450.490.60.680.750.790.860.98

1.21.21.461.761.952.212.42.632.933.383.684.24,655.25

5.335.85

0.260.320.460.460.520.60.660.80.921.051,061.191.32

1.651.65I .992.392.652.993.33.573.974.625.025.76.357.25

8.278.95

-762-734-944-769-751-789-772-883-936-961-810-779-772

-920-754-879-985-971-982-935-895-8S2-956-904-892-869-910

-840-814

1040980

1280106010201110I 070123012701300113010801070

12501040122013501340137012901240122013201250I 24012001250

11401120

‘1 The values specified fort are nominal values. In the case of Group 3 springs, the values given in parentheses apply fort (reducedthickness). Limit deviations for thickness are specified in 8.2.

‘) Design (compressive) stresses at the point designated O&f,that is on the conical surface of the spring,

‘) The values specified apply for the largest tensile stresses on the lower edges of the spring. The values specified with an asterisk (*)apply to the pOint designated II, those without an asterisk, to the point designated III.

NOTE — In the case of springs with ground ends (see Group 3 in 5), the desired spring load, F (where s is equal to approximately0.75 ho), is to be obtained by reducing the thickness of single discs, t, which then gives the value f’. In the case of spring series Aand B, t’ shall be equal to approximately 0.94 t, and in the case of spring series C, it shall be equal to approximately 0.96 r.

7 DESIGNATION

Designation shall include type of disc spring, nominaloutside diameter, group of disc spring and the numberof this standard.

Example:

A disc spring of Type A having outside diameterD,= 40 of Group 2 shall be designated as:

5

Disc Spring A40GR2-IS 12511 (Part 1)

8 TOLERANCES

8.1 Tolerances on Diameter

8.1.1 For all springs, tolerance class h12shall apply forthe outside diameter D.. Tolerance class Hlz shall applyfor the inside diameter Di.

IS 12511 (Part 2) :2004

8.2 Tolerances on Thickness — (see Table 5).

Table 5 Thickness

Group tort” Limit Deviations

(1) (2) (3)

1 From 0.2 to 0.6 +0.02-0.06

Over 0.6 to below 1.25 +0.03–0.09

2 From 1.25 to 3.8 +0.04-0.12

Over 3,8 up to 6.0 +0.05-0.15

3 Over 6.0 up to 14.0 * 0.10

NOTE — In the case of Group 3 springs, the limit deviationsspecified apply to the reduced thickness, f,

8.3 Tolerances on Free Overall Height, 10—(see Table 6).

Table 6 Overall Height

Group t Limit Deviations

(1) (2) (3)

1 Less than 1.25 +0.10-0.05

From 1.25 to 2.0 +0. I5-0.08

2 Over 2.0 up to 3.0 + 0.20-0.10

Over 3.0 up to 6.0 +0.30-0.15

3 Over 6.0 up to 14.0 ● 0.30

9 TOLERANCE ON SPRING LOAD

9.1 Single Discs

The static spring load F, of a single disc in the initialposition (10–s) shall be determined for a spring in theloaded state, using a suitable lubricant. The flat plates

between which the spring is to be compressed shall behardened, ground, and polished.

Under normal circumstances, the values specified inTable 7 shall apply.

Table 7 Spring Load

(Clauses 9.1 and 11.1)

Group t Limit Deviations forFat [e- 0.7S hO

Percent

(1) (2) (3)

I Less than 1.25 +25–7.5

2 From 1,25 to 3,0 +15–7.5

Over 3.0 up to 6.0 +10-5

3 Over 6.0 up to 14.0 *5

NOTE — To comply with the specified tolerances, it isnecessary to exceed the tolerance values specified for 1,,(seeTable 6).

9.2 Springs Stacked in Series

9.2.1 Ten single discs stacked in series shall be usedto determine the deviation in load between the loadingcurve and the unloading curve of springs stacked inseries. The individual discs shall be centred about amandrel in compliance with 19. The flat plates betweenwhich the spring is to be compressed shall be hardened,ground, and polished.

9.2.2 Prior to testing, the spring shall be compressedto -twice its design load, F (where s = 0.75 hO).At(Lo -7.5 ho) the spring load determined for theunloading curve shall make up at least the minimumpercentages specified in Table 8 of the spring loaddetermined for the loading curve (see Fig. 2).

Spring load, F ~

@

c- 40.=Q Measurina mints

I

iI

i

FIG. 2 MEASURING POINTSFORLOADINGANDUNLOADINGCURVES

6

Table 8 Minimum Spring Load

(Clause 9.2.2)

S1 Group Minimum Spring Load(Unloading),No. As a Percentage,for Spring Series

.A B c

(i) (2) (3) (4) (5)

i) 1 90 90 85ii) 2 92.5 92.5 87.5iii) 3 95 95 90

9.2.3 Within certain tolerances, the form of the actualindividual discs will deviate from the geometricallyideal form of the stack. Together with the effect offriction, this results in a loacVdeflection curve for thestack that differs from that established for the sum ofthe results for the individual discs. Stacks of springsshall normally be tested with the arrangement used inpractice.

10 CLEARANCE BETWEEN SPRING ANDCENTERING ELEMENT

Means shall be provided to keep the spring in position,these being preferably internal, such as a mandrel. Inthe case of external positioning, a sleeve is preferred.

IS 12511 (Part 2): 2004

The recommended amount of play between the springand such a centring element is specified in Table 9,as function of the outside or inside diameter of thespring.

Table-9 Play

SINo.(1)

Oii)iii)iv)v)vi)vii)VK1)

D, or De

(2)

Up to 16Over 16 up to 20Over 20 up to 26Over 26 up to 31.5Over 31.5 up to 50Over 50 up to 80Over80 up to 140Over 140 up to 250

ApproximatePlay

(3)

0.20.30.40.50.60.811.6

11 PERMISSIBLE SET

11.1 Following heat treatment, each spring shall beprestressed in such a manner that the values specifiedin Table 7 are complied with when the sprrng iscompressed to twice its design load, F (s =0.75 hO).

11.2 In the case of springs subject to static loading theguideline values for relaxation illustrated in Fig. 3 maynot be exceeded.

- —– After 48 hours_ — After 1000 hours

I 10~ YO

~ “k8 /

Ic- 6 /0.= /“g

40“

~ r/’

v

‘2 “ T/d+ ~20C’c

o~-” -- -

Series A t 1 I 1 I-500 -1000 -1500 -2000

Series B I I I I

-500 -1000 -1500Series C I I I 1

-500 -1000N/mm2 -1500ao~~

FIG. 3 ILLUSTRATIONOF PERMISSIBLERELAXATIONFORSPRINGSMADE FROMHIGHGRADECHROMIUM

ALLOY STEEL ORCHROMKJM— VANADIUMALLOY STEEL

7

IS 12511 (Part 2): 2004

11.3 Where the service temperature exceeds 100°C,the spring manufacturer shall be consulted.

12 STRESSES IN SPRINGS SUBJECT TOSTATIC LOA-DING OR MODERATE FATIGUECONDITIONS

Steel that are subject to static loading or to moderatefatigue conditions, the design stress at the pointdesignated CM4(ao~), shall be approximately equal tothe yield strength, Re of the material used. At higherstresses the springs may suffer from creep or relaxation(see 11).

13 STRESSES IN SPRINGS SUBJECT TOFATIGUE LOADING

13.1 Minimum Initial Deflection to Avoid Cracking

Springs subject to fatigue loading shall be designedand installed in such a way that the initial deflection isfrom 0.15 hOto 0.20 hO, in order to avoid cracking atthe upper inner edge {point I, see Fig. 1) as a result ofresidual stresses from the setting process.

13.2 Stresses

13.2.1 Figures 4 to 6 illustrate the endurance life ofdisc springs subject to fatigue loading that have not

been shot peened. They speci~ guideline values forthe range of stress c~ as a function of the minimumstress cruat three different numbers of stress cycles N,namely, where N is less than or equal to 2 x 10s, equalto 10s and equal to 5 x 105. Intermediate values forother numbers of stress cycles maybe estimated basedon this information.

13.2.2 The information given in Fig. 4 to Fig. 6represents the results of laboratory testing using fatiguetesting equipment capable of producing sinusoidalloading cycles and the statistical results obtained for a99 percent probability of endurance life. The test pieceswere ten single discs with hardened surfaces, stackedin series, designed for use at ambient temperature,provided with an internal or external centring elementwith a smooth finish, having a minimum initialdeflection S1, fi’om0.15 hOto 0.20 hO.

13.2.3 To ensure the expected endurance life of springs,they shall be protected from mechanical darnage andother adverse conditions.

13.2.4 The stress cycles in practice are generally notsinusoidal in form. Where additional types of loading(for example sudden dynamic loading or that whichresults from resonance) act on the spring, it may beassumed that their endurance life will be shorter. Where

C.-T “o 200 400 600 800 1000 N/iun21400&

Minimum stress, w ~

FIG. 4 GRAPHICALREPRESENTATIONOF ENDURANCELIFE OF SPRINGS-WHERE‘t’

8

N LESS THAN1.25 mm

IS 12511 (Part 2) :2004

“o 200 400 600 800 1000 NAm2 1400

Minimum stress, ~ ~

FIG. 5 GRAPHICALREPRESENTATIONOF ENDURANCELIFE OF SPRINGSWHERE 1.25 mm < t<6 mm

1400N/mm2

t~o

uc

:

1200

1000

#c

%

.-0 200 400 600 800 WOO N/k+ 1400

Minimum stress, q ~

FIG. 6 GRAPHICALREPRESENTATIONOF ENDURANCELIFE OF SPRINGSWHERE 6 mm < t <14 mm

9

IS 12511 (Part 2) :2004

such is the case, the values given in the above figuresshall be converted by appropriate factors of safety. Thespring manufacturer being consulted where necessary.

14 MATERIAL

Disc spring shall be made from any of the materialspecified below:

a) Steel Grade 50Cr4V2 conforming to IS 2507;and

b) For small sizes only in Group 1up to 0.9 mmsteel Grade 70C6 conforming to IS 2507.

15 FINISH

1-5.1 Manufacturing Methods and Surface Quality

A distinction is made among the following three groups(see 5 and Table 10).

Table 10 Surface Roughness of VariousManufacturing Processes

Group Manufacturing Surface Roughness’)Process ym

Upper and Outer andLower Inner FacesSurface Edges

(1) (2) (3) (4)

1 Stamped, cold formed, Ra<3.2 /la <12.5edges rounded

22) Stamped, cold formed De Ra <6.3 Ra <6.3and Di turned, edgesrounded

Stamped, cold formed, Ra <6.3 Ra <3.2edges roumded

3 Cold or hot formed, turned Ra <12.5 Ra <12.5on all sides, edges rounded

!) The Values specified do not apply to shot peened springs.Z)Un\ess otherwise specified, the particular manufaCtrrring

process shall be up to the manufacturer (see 6 and 7).

15.2 The surface shall be free from defects such asscars, cracks and the effects of corrosion.

16 HARDNESS SURFACE AND SCRAGGING

16.1 The partial decarburization of disc springs atlerquenching and tempering shall not exceed 3 percentof the disc thickness.

16.2 Total decarburization shall not be permitted.

16.3 For static spring, the hardness of disc springs shallbe within the range of 42 to 52 HRC (in case of Group1 disc spring, the hardness shalI be measured inaccordance with IS 1586 in order to achieve good fatiguestrength value with low relaxation. The load/lengthrelaxation after 107cycles shall not exceed 6 percent.

16.4 The surface must be flawless, that is, free frompit marks, cracks and corrosion.

16.5 Subsequent to heat treatment, every disc springmust be subjected to scragging in such a way that afterloading at twice the-spring force F fors x0.75 hO,theoverall height 10of the spring does not alter beyondthe permissible deviation limits (see 8.3).

16.6 Surface Hardening

The disc springs exposed to dynamic loading arerecommended to undergo shot peening in accordancewith IS 7001.

16.7 Protection Against Corrosion

16.7.1 The type of corrosion protection applied willdepend on the intended application of the disc springs.This can be achieved among other methods by.phosphating, burnishing or the application of protectivemetallic coatings, such as zinc or cadmium.

16.7.2 The processes are in use these days whichinvcdve the deposition of metallic coatings fromaqueous solutions cannot with absolute certaintyexclude the risk of hydrogen induced brittle fi-acturein the case of disc springs. For components with ahardness exceeding 40 HRC, the risk of brittle fractureis if anything even greater, This means that specialprecautions must be taken in respect of materialselection, heat treatment and surface treatment.Therefore, when ordering electroplated disc springs,it is recommended to have prior consultation with thespring manufacturer.

16.7.3 Galvanic plating should, however, be avoidedin the case of disc springs likely to be subjected toalternating loading, in favour of processes which donot have any adverse effects.

16.8 Guide Elements and Sealing Faces

The guide elements and sealing faces shall, wherepossible, be case-hardened (depth of case-hardening0.8 mm) and exhibit a minimum hardness of 55 HRC.The surface of the guide element shall be smooth andpreferably ground.

17 CALCULATION

17.1 The spring forces F for s =. 0.75 hO and thetheoretical stresses c fors = 0.75 hOat location H andIII, respectively have already been specified in thisstandard for disc springs in spring steel withE = 206000 N/mmz. Attention is drawn to necessityof calculating lower and upper limits of stress atlocation H or HI in the case of fatigue loading and ofcomparing these calculated values with a fatiguestrength diagram.

17.2 The standardized disc springs are capable of beingstatically loaded up tos = 0.75 hOwithout any risk ofsetting effects [see 12511 (Part 1)].

10

IS 12511 (Part 2) :2004

18 TESTING

1.8.1 Check of Dimensions and Other SpringCharacteristics — (see Table 11).

Table 11 AQL Value of Spring Characteristics

SI Spring Characteristics AQL ValueNo.

(1) (2) (3)

i) Major characteristics: ISpring load, F (wheres = 0.75 ho)Outside diameter, DeInside diameter, Di

ii) Minor characteristics: 1.5Free overall height in initial position, 10Spring thickness, tortSurface roughness, R,

18.2 Hardness Testing

Rockwell hardness testing shall be carried out inaccordance with IS 1586. The indentation shall bemade on the upper surface of the spring, at a pointthat lies centrally between the inner and outeredges.

19 OTHER RELEVANT REQUIREMENTS

Where possible, the centering element and the seat shallbe made from case-hardened materials, with a casedepth of about 0.8 mm, and have a hardness of 55 HRC.The surface of the centering element shall be smoothand, where possible polished. It shall be permitted touse unhardened centering elements where the springis subject to static loading.

11

IS 12511 (Part 2) :2004

ANNEX A

(Foreword)

COMMITTEE COMPOSITION

Automotive Springs and Suspension Systems Sectional Committee, TED 21

Organization

Tata Motors Ltd, Jamsheilpur

Akal Springs Pvt Ltd, Ludhiana

All India Springs Manufacturers Association, Mumbai

Ashok Leyland Ltd, Chennai

Association of State Road Tramsport Undertakings,New Delhi

Central Institute of Road Transport, Pune

Central Mechanical Engineering Research Institute,Durgapur

Conventry Springs & Engineering Co Pvt Ltd, Kolkata

CQA (OFV) Vehicle Factory, JabalpurGabriel India Ltd, Mumbai

Jai Parabolic Springs Ltd, Chandigarh

Jamna Auto Industries Ltd, Yamrrna Nagar

Kemen Springs Pvt Ltd, Mumbai

Mack Springs Pvt Ltd, Thane

Mahindra & Mahindra Ltd, Nashik

Maruti Udyog Ltd, Gurgaon

Ministry of Heavy Industry & Public Enterprises, New Delhi

Research Designs & Standards Organization, Lucknow

Stumpp, Schuele & Somappa Pvt Ltd, Bangalore

The Automotive Research Association of lndi~ Pune

Upper India Steel Mfg & Engg Co Ltd, Ludhiana

Vehicle Factory, Jabalpur

BIS Directorate General

Representative(s)

SHRKA. G. PRADHAN(Chairman)Smu K. GOPALAKRISHNA(Alternate)

GENERALMANAGER

Smu A. A. MIRCHANDANI

Swu APPALARAJUSrsruU. JAUOUSHNA(Alternate)

Smu A. S. LAKRASW P. M. Pnm (Alternate)

SswtrN. R. KACHARSSmrr P. S. Mrmou (A/terns/e)

DR J. BASUDR T. K. PAUL(A[ferrrate)

SHRIA. BAPNASmu A. S. Kosu-I‘(,4/fernate)

GENERALMANAGERSrrruK. SUNOARARAMAN

Smu S. K. BHAUMSCK(Alternate)

SHSUSUNILHAROLIYA

Smu D. S. GILLSwu B. K. KHANDELWAL(Alternate)

Smu P. K. MIRCHANDANI

SHRKD. V. SHARMA

Smrr Wwmsu DESHMUKHSmu KAILASHJAT (Alternate)

SHRtD. N. DAVESmu G. VUAYAN(Alternate)

SHRIS. K. .BrwuISmu R. K. TRtPATHI(Alternate)

Jowr DIRECTOR(STANDARDS)ASSISTANTDESIGNENGINEER

SHRIB. S. MOOKHERIEESmu N. C. SRINIVASAN(Alternate)

Smu S. RAJU

Sruu R. P. ENGIRA

!?mr M. K. MISHRA.Sruu R. LODWAL(Alternate)

SHrrrK. K. VAsmmr,+, Director & Head (TED)[Representing Director General (.Ex-@,~cio)]

‘Member-SecretarySHRIP. K. SHARMA

Director (TED), BIS

12

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau oflndian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goodsand attending to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publications), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of‘BIS Catalogue’ and ‘Standards: Monthly Additions’.

This Indian Standard has been developed from Doc : No. TED 21 (337).

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters :

Manak Bhavan, 9 BahadurShah Zafar Marg, New Delhi 110002 Telegrams : ManaksansthaTelephones :23230131,23233375,2323 9402 (Common to all offices)

Regional Offices : Telephone

Central : ‘Manak Bhavan, 9 Bahadur Shah Zafar Marg

{

23237617NEW DELHI 110002 23233841

Eastern : 1/14 C.I.T. Scheme VII M, V. I. P. Road, Kankurgachi

{

23378499,23378561KOLKATA 700054 23378626,23379120

Northern : SCO 335-336, Sector 34-A, CHANDIGARH 160022

{

603843609285

Southern : C.I.T. Campus, IV Cross Road, CHENNAI 600113

{

22541216,2254144222542519,22542315

Western : Manakalaya, E9 MIDC, Marol, Andheri (East)

{

28329295,28327858MUMBAI 400093 28327891,28327892

Branches : AHMEDABAD. BANGALORE. BHOPAL. BHUBANESHWAR. COIMBATORE. FARIDABAD.GHAZIABAD. GUWAHATI. HYDERABAD. JAIPUR. KANPUR. LUCKNOW. NAGPUR.NALAGARH. PATNA. PUNE. RAJKOT. THIRUVANANTHAPURAM. VISAKHAPATNAM.

Printed at Prabhat Offset Press, New Delhi-2