ISO 19690-2:2018

Disc springs — Part 2: Technical specifications

This document specifies two different grades of disc springs. Grade A defines basic requirements of disc springs for static applications with low and moderate performance. Springs manufactured according to Grade A are not used for dynamic applications. Grade B defines requirements on disc springs especially used for dynamic applications and high performance static applications. Disc springs according to Grade B ensure a better quality by higher demands on manufacturing processes and tolerance requirements. Grade B includes graphs showing the guaranteed fatigue life such as a function of stress.

Rondelles ressorts — Partie 2: Spécifications techniques

General Information

• Status: Published
• Publication Date: 19-Sep-2018
• ICS: 21.160 - Springs
• Technical Committee: ISO/TC 227 - Springs
• Drafting Committee: ISO/TC 227 - Springs
• Current Stage: 9093 - International Standard confirmed
• Start Date: 12-Dec-2023
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 10052:2021 - Acoustics — Field measurements of airborne and impact sound insulation and of service equipment sound — Survey method
• Effective Date: 06-Jun-2022
• Amended By: ISO 19690-2:2018/Amd 1:2025 - Disc springs — Part 2: Technical specifications — Amendment 1: Durability chart for not shot peened springs (group 3)
• Effective Date: 03-Aug-2024

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19690-2
First edition
2018-09
Disc springs —
Part 2:
Technical specifications
Ressorts à disques —
Partie 2: Spécifications techniques
Reference number
©
ISO 2018
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and units . 2
5 Dimensions and designation . 3
5.1 General . 3
5.2 Disc spring groups . 5
5.3 Dimensional series . 5
6 Grade A — Basic performance requirements for static applications .5
6.1 Material . 5
6.2 Manufacturing process. 5
6.3 Permissible stresses . 6
6.4 Presetting . 6
6.5 Surface condition and corrosion protection . 6
6.6 Tolerances . 7
6.6.1 Thickness . 7
6.6.2 External- internal diameter and coaxiality . 7
6.6.3 Free height. 8
6.6.4 Spring load . 8
6.7 Clearance between disc spring and guiding element . 8
6.8 Hardness . 9
6.9 Appearance . 9
7 Grade B — Requirements on disc springs for dynamic applications and high-
performance static applications . 9
7.1 Material . 9
7.2 Manufacturing process. 9
7.3 Permissible stresses .11
7.3.1 Static load .11
7.3.2 Dynamic loading.11
7.4 Shot peening .14
7.5 Presetting .14
7.6 Creep and relaxation .14
7.7 Surface condition and corrosion protection .16
7.8 Tolerances .17
7.8.1 Thickness .17
7.8.2 External-internal diameter and coaxiality.17
7.8.3 Free height.18
7.8.4 Spring load .18
7.9 Clearance between disc spring and guiding element .19
7.10 Hardness .19
7.11 Appearance .19
Annex A (informative) Spring dimensions .20
Annex B (informative) Testing .25
Annex C (normative) Representative material grades.28
Bibliography .29
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 227, Springs.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
A list of all parts in the ISO 19690 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 19690-2:2018(E)
Disc springs —
Part 2:
Technical specifications
1 Scope
This document specifies two different grades of disc springs.
Grade A defines basic requirements of disc springs for static applications with low and moderate
performance. Springs manufactured according to Grade A are not used for dynamic applications.
Grade B defines requirements on disc springs especially used for dynamic applications and high
performance static applications. Disc springs according to Grade B ensure a better quality by higher
demands on manufacturing processes and tolerance requirements. Grade B includes graphs showing
the guaranteed fatigue life such as a function of stress.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
ISO 683-1, Heat-treatable steels, alloy steels and free-cutting steels — Part 1: Non-alloy steels for quenching
and tempering
ISO 683-2, Heat-treatable steels, alloy steels and free-cutting steels — Part 2: Alloy steels for quenching and
tempering
ISO 6507 (all parts), Metallic materials — Vickers hardness test
ISO 6508 (all parts), Metallic materials — Rockwell hardness test
ISO 16249, Springs — Symbols
ISO 26909, Springs — Vocabulary
EN 1654, Copper and copper alloys — Strip for springs and connectors
EN 10083-1, Quenched and tempered steels — Technical delivery conditions for special steels
EN 10083-2, Quenched and tempered steels — Technical delivery conditions for unalloyed quality steels
EN 10083-3, Quenched and tempered steels — Technical delivery conditions for boron steels
EN 10089, Hot-rolled steels for quenched and tempered springs — Technical delivery conditions
EN 10132-4, Cold-rolled narrow steel strip for heat treatment — Technical delivery conditions — Part 4:
Spring steels and other applications
EN 10151, Stainless steel strip for springs — Technical delivery conditions
JIS G 3311, Cold-rolled special steel strip
JIS G 4801, Spring steels
JIS G 4802, Cold-rolled steel strip for springs
ASTM A240, Standard specification for chromium and chromium-nickel stainless steel plate, sheet, and
strip for pressure vessels and for general applications
ASTM A332, Specification for nickel-chromium-molybdenum steel bars for springs
ASTM A506, Standard specification for alloy and structural alloy steel, sheet and strip, hot-rolled and
cold-rolled
ASTM A568, Standard specification for steel, sheet, carbon, structural, and high-strength, low-alloy, hot-
rolled and cold-rolled, General requirements for
ASTM A666, Standard specification for annealed or cold-worked austenitic stainless steel sheet, strip, plate,
and flat bar
ASTM A682, Standard specification for steel, strip, high carbon, cold rolled, General requirements for
ASTM A684, Standard specification for steel, strip, high carbon, cold rolled
ASTM A689, Standard specification for carbon and alloy steel bars for springs
ASTM A693, Standard specification for precipitation-hardening stainless and heat-resistant steel plate,
sheet, and strip
ASTM B103, Standard specification for phosphor bronze pate, sheet, strip, and rolled bar
ASTM B194, Standard specification for copper-beryllium alloy plate, sheet, strip, and rolled bar
ASTM B196, Standard specification for copper-beryllium alloy rod and bar
GB/T 1222, Spring steels
BS 970-2, Specification for wrought steels for mechanical and allied engineering purposes: Requirements
for steels for the manufacture of hot-formed springs
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 26909 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Symbols and units
For the purposes of this document, the symbols and units given in ISO 16249, Table 1 and Figure 1 apply.
Table 1 — Symbols and units for design calculation
Symbol Unit Parameter
b mm width of scar (see Figure 2)
r
D mm external diameter of spring
D mm diameter of centre of rotation
d mm internal diameter of spring
NOTE  1 N/mm = 1 MPa.
a
r is not chamfered unless otherwise agreed between customer and supplier.
2 © ISO 2018 – All rights reserved

Table 1 (continued)
Symbol Unit Parameter
modulus of elasticity of material (carbon steel and carbon alloy steel:
E N/mm
206 000 N/mm )
F N spring load
F N design spring load when spring is in the flattened position
c
F N spring load at the time of combining springs
G
F N spring test load at H
t t
H mm height of spring when measuring spring test load, H = H – 0,75h
t t 0 0
H mm free height of spring
h mm clean cut (see Figure 2)
s
h mm initial cone height of spring without flat bearings, h = H – t
0 0 0
h , mm initial cone height of spring with flat bearings, h , = H – t
0 f 0 f 0 f
i — number of springs combined in series
L mm free height at the time of combining springs
N — number of cycles for fatigue life
n — number of springs piled in parallel
OM — point at upper surface of the spring perpendicular to the centre line at point P
P — theoretical centre of rotation of disc cross section
R N/mm spring rate
a
r mm radius at edge
s mm deflection of spring
s mm deflection of stack
G
s mm deflection of spring preloaded
t mm thickness of spring
t mm reduced thickness of single disc spring with flat bearings
f
V mm length of lever arms
V mm length of lever arms with flat bearings
f
ΔF N spring load loss
Δh mm initial cone height loss of spring
ν — Poisson’s ratio of material
σ N/mm alternative stress, σ = σ – σ
H H max min
σ N/mm stress at position OM
OM
σ N/mm maximum fatigue stress
max
σ N/mm minimum fatigue stress
min
σ N/mm stress at position I
I
σ N/mm stress at position II
II
σ N/mm stress at position III
III
σ N/mm stress at position IV
IV
NOTE  1 N/mm = 1 MPa.
a
r is not chamfered unless otherwise agreed between customer and supplier.
5 Dimensions and designation
5.1 General
Figure 1 illustrates a single disc spring, including the relevant positions of loading.
a) Without flat bearings — Group 1 and Group 2
b) With flat bearings — Group 3
Key
D external diameter of spring
D diameter of centre of rotation
d internal diameter of spring
F spring load
H free height of spring
OM point at upper surface of the spring perpendicular to the centre line at point P
P theoretical centre of rotation of disc cross section
a
r radius at edge
t thickness of spring
t reduced thickness of single disc spring with flat bearings
f
V length of lever arms
V length of lever arms with flat bearings
f
I position I
II position II
III position III
IV position IV
a
r is not chamfered unless otherwise agreed between customer and supplier.
Figure 1 — Single disc spring (sectional view), including the relevant positions of loading
4 © ISO 2018 – All rights reserved

5.2 Disc spring groups
Table 2 shows the disc spring groups.
Table 2 — Disc spring groups
Group t With flat bearings and reduced thickness
mm
1 0,2 ≤ t < 1,25 No
2 1,25 ≤ t ≤ 6,0 No
3 6,0 < t ≤ 14,0 Yes
5.3 Dimensional series
Table 3 shows the dimensional series.
Table 3 — Dimensional series
Dimensional series h /t t /t D/t
0 f
A ≈ 0,40 ≈ 0,94 ≈ 18
B ≈ 0,75 ≈ 0,94 ≈ 28
C ≈ 1,30 ≈ 0,96 ≈ 40
NOTE Refer to Annex A for typical disc spring dimensions.
6 Grade A — Basic performance requirements for static applications
6.1 Material
Unless otherwise agreed between customer and supplier, disc springs should be made from material
conforming to Table 4.
6.2 Manufacturing process
Unless otherwise agreed between customer and supplier, disc springs should be made by the
manufacturing process shown in Table 4.
Table 4 — Manufacturing process and material
t
Group Manufacturing process Material
mm
Stamping,
Carbon steel
1 0,2 ≤ t < 1,25 cold or hot forming,
or alloy steel
edge rounding
Stamping,
b
cold or hot forming, Carbon steel
2 1,25 ≤ t ≤ 6,0
a
D and d turning , or alloy steel
edge rounding
Cold or hot forming,
turning on all sides,
edge rounding
or
3 6,0 < t ≤ 14,0 Alloy steel
c
Stamping ,
cold or hot forming,
D and d turning,
edge rounding
a
D and d turning are optional.
b
Carbon steel used 1,25 ≤ t ≤ 2,0 only.
c
Stamping without D and d turning is not permitted.
6.3 Permissible stresses
For disc springs made of steels according to materials shown in Table 4, which are subject to static
loading, the design stress, σ , at maximum deflection shall not exceed 1 400 N/mm .
OM
NOTE The design stress, σ , is derived from the formulae given in ISO 19690-1.
OM
6.4 Presetting
After heat treatment, each disc spring shall be loaded until it is in the flat position. After loading the
disc spring with twice its spring test load, F , the tolerances for the spring load as specified in Table 8
t
shall be met.
6.5 Surface condition and corrosion protection
The surface treatment should be agreed between customer and supplier.
The surface shall be free from defects such as scars, cracks and corrosion.
As disc springs are easy to be rusted, it is preferable to apply suitable corrosion protection to them.
Whether and which corrosion protection is to be provided shall depend on the particular spring
application. Suitable corrosion protections include phosphating, black finishing and the application of
protective metallic coatings such as zinc or nickel. This shall be agreed between customer and supplier.
It is possible that the galvanizing processes using aqueous solutions that are currently available do
not preclude the risk of hydrogen embrittlement. Disc springs with a hardness exceeding 40 HRC are
more prone to the risk of hydrogen embrittlement than softer springs. Special care shall therefore
be taken when selecting the material, manufacturing process, heat treatment and surface treatment.
When ordering disc springs with galvanic surface protection, it is advisable to consult the spring
manufacturer.
For disc springs, galvanic surface protection should be avoided.
Phosphating and oiling form the standard corrosion protection for disc springs.
6 © ISO 2018 – All rights reserved

6.6 Tolerances
6.6.1 Thickness
The tolerances on thickness are shown in Table 5.
For information on testing of thickness, see Annex B.
Table 5 — Tolerances on thickness
Dimensions in mm
Group t Tolerance
+00, 3
0,2 ≤ t ≤ 0,6
−00, 6
+00, 6
0,6 < t < 1,25
−00, 9
+00, 9
1,25 ≤ t ≤ 3,8
−01, 2
+01, 0
3,8 < t ≤ 6,0
−01, 5
3 6,0 < t ≤ 14,0 ±0,15
6.6.2 External- internal diameter and coaxiality
The tolerances on external diameter and internal diameter are shown in Table 6. The tolerances are
determined by the tolerance grade IT13, which is specified in ISO 286-2.
Coaxiality tolerance: 2 × IT13
For information on testing of external diameter and internal diameter, see Annex B.
Table 6 — Tolerances on external diameter and internal diameter
Dimensions in mm
D or d Tolerance, D Tolerance, d
0 +01, 8
over 3 up to 6
−01, 8
0 +02, 2
over 6 up to 10
−02, 2
0 +02, 7
over 10 up to 18
−02, 7
0 +03, 3
over 18 up to 30
−03, 3
0 +03, 9
over 30 up to 50
−03, 9
0 +04, 6
over 50 up to 80
−04, 6
0 +05, 4
over 80 up to 120
−05, 4
0 +06, 3
over 120 up to 180
−06, 3
0 +07, 2
over 180 up to 250
−07, 2
6.6.3 Free height
The tolerances on free height are shown in Table 7.
For information on testing of free height, see Annex B.
Table 7 — Tolerances on free height
Dimensions in mm
Group t Tolerance
+01, 0
0,2 ≤ t < 1,25
−00, 5
+01, 5
1,25 ≤ t < 2,1
−00, 8
+02, 0
2 2,1 ≤ t < 3,5
−01, 0
+03, 0
3,5 ≤ t ≤ 6,0
−01, 5
3 6,0 < t ≤ 14,0 ±0,30
6.6.4 Spring load
The spring load, F shall be determined at test height H = H – 0,75h . The tolerances on spring loads
t, t 0 0
are shown in Table 8. The measurement is taken while loading between flat plates, using a suitable
lubricant. The flat plates shall be hardened, ground and polished. In the case of stacking the springs, the
tolerance on spring load should be agreed between customer and supplier.
To comply with the specified load tolerances, it can be necessary to exceed the tolerance values specified
for H and t.
Table 8 — Tolerances on spring load
Tolerance
t
F (H = H – 0,75h )
Group t t 0 0
mm N
+30%
0,2 ≤ t < 1,25
−10%
+20%
1,25 ≤ t ≤ 3,0
−10%
+15%
3,0 < t ≤ 6,0
−75, %
3 6,0 < t ≤ 14,0 ±10 %
6.7 Clearance between disc spring and guiding element
A guiding element is necessary to keep the disc spring in position. This should preferably be a mandrel.
In the case of external positioning, a sleeve is preferred.
Table 9 shows clearance of guide.
8 © ISO 2018 – All rights reserved

Table 9 — Clearance of guide
Dimensions in mm
D or d Clearance of diameter
up to 15 0,2
over 15 up to 20 0,3
over 20 up to 26 0,4
over 26 up to 31,5 0,5
over 31,5 up to 45 0,6
over 45 up to 75 0,8
over 75 up to 140 1,0
over 140 up to 250 1,6
6.8 Hardness
The hardness of disc springs shall lie within the range of 42 HRC to 52 HRC.
For group 1 disc springs, the hardness shall be determined according to Vickers (425 HV10 to 510 HV10).
After heat treatment, the disc spring shall not exhibit a depth of decarburization exceeding 3 % of its
thickness.
Vickers hardness testing shall be carried out according to ISO 6507 (all parts) and Rockwell hardness
testing according to ISO 6508 (all parts).
6.9 Appearance
The appearance testing should be carried out according to B.3.6. The surface shall be free from cracks,
impedimental defects, burrs, corrosion and so forth.
In addition, there shall be no sharp edge on the inner and outer circumferences.
7 Grade B — Requirements on disc springs for dynamic applications and high-
performance static applications
7.1 Material
Disc springs shall be made from material conforming to Annex C.
7.2 Manufacturing process
Disc springs shall be made in accordance with the manufacturing process shown in Table 10 and
Figure 2.
Table 10 — Manufacturing process and material
t
Group Manufacturing process Material according to Annex C
mm
Stamping,
cold or hot forming,
edge rounding
or
Cold rolled carbon steel
Stamping,
or cold rolled alloy steel
cold or hot forming,
1 0,2 ≤ t < 1,25 or hot rolled if all surfaces are machined
D and d turning,
to remove scale and surface defects ac-
edge rounding
cording to Annex C
or
b
Fine blanking ,
cold or hot forming,
edge rounding
a
Stamping ,
cold or hot forming,
c
Cold rolled carbon steel
D and d turning,
or cold rolled alloy steel
edge rounding
2 1,25 ≤ t ≤ 6,0 or hot rolled if all surfaces are machined
or
to remove scale and surface defects ac-
b
Fine blanking ,
cording to Annex C
cold or hot forming,
edge rounding
Cold or
...