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WC 669.14/. 15.018.298.3
IS0
I NT ERN AT I ON A L ORGAN IZ AT1 O N FOR STAND AR D IZATiO N
1 SO R ECO M M EN DATI O N
R 683/ I
HEAT-TREATED STEELS, ALLOY STEELS
AND FREE-CUTTING STEELS
PART I
QUENCHED AND TEMPERED UNALLOYED STEELS
1st EDITION
March 1968
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 68311, Heat-treated steels, alloy steels and free-cutting steels -
Part I : Quenched and tempered unalloyed steels, was drawn up by Technical Committee ISOlTC 17,
Steel, the Secretariat of which is held by the British Standards Institution (BSI).
Work on this question by the Technical Committee began in 1958 and led, in 1965, to the
adoption of a Draft IS0 Recommendation.
In January 1966, this Draft IS0 Recommendation (No. 916) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature,
by the following Member Bodies :
Romania
Argentina Germany
Australia Hungary Spain
Austria India Sweden
Switzerland
Belgium Israel
Brazil Italy Turkey
Canada Japan U.A.R.
Chile Korea, Rep. of United Kingdom
Czechoslovakia Netherlands U.S.A.
Denmark Norway U.S.S.R.
Yugoslavia
Finland Poland
One Member Body opposed the approval of the Draft :
France
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council
which decided, in March 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 683/I-1968 (E)
IS0 Recommendation
R 68311 March 1968
HEAT-TREATED STEELS, ALLOY STEELS
AND FREE-CUTTING STEELS
PART I
QUENCHED AND TEMPERED UNALLOYED STEELS
1. SCOPE
1.1 This IS0 Recommendation covers unalloyed wrought steels for mechanical purposes usually
intended for use
in the quenched and tempered condition, or
(a)
(b) in the austempered condition,
with or without subsequent cold reduction.
1.2 For the purpose of simplification the steels covered by this IS0 Recommendation in both con-
ditions are called ‘quenched and tempered steels’, and both conditions are summarized under
the term ‘quenched and tempered’.
I .3 This IS0 Recommendation comprises the two series of steels, listed in Table 2, which differ in
their maximum phosphorus and sulphur contents.
2. REQUIREMENTS
2.1 Production processes
Unless otherwise agreed in the order, the processes used in making the steel and the product are
left to the discretion of the manufacturer, but the steel should be killed. When he so requests,
the user should be informed what steelmaking process is being used.
2.2
Chemical composition and mechanical properties
2.2.1 The steels covered by this IS0 Recommendation should be ordered and delivered in accor-
dance with Table 1.
TABLE 1 - Types of condition of delivery
Types of condition of delivery*
Requirements
1 l(a) 3 3(a) 4 4(a) 5 6
Chemical composition xxxxxxxx
Hardness in a condition of delivery
other than quenched and tempered -x-x-x- -
Mechanical properties of
quenched and tempered test bars of
16 mm diameter
- quenched and tempered ruling sections
- quenched and tempered product in
final dimensions
- quenched and tempered product sub-
sequently cold-reduced to final
dimensions
*
The numbers indicating the types of condition of delivery follow a co-ordinated series of numbers throughout all
relevant IS0 Recommendations.
The type of condition of delivery according to Table 1 should be stated at the time of
enquiry and order.
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ISO/R 683/I-1968 (6)
2.2.2 The chemical composition expressed by the cast analysis should be in accordance with
Table 2.
TABLE 2 ~ Types of steel and chemical composition guaranteed (applicable to cast analysis)*
Type
c 70
of steel
0.050 0.050
I EiZe 1 0.22 to 0.29 0.1 5 to 0.40 0.40 to 0.70
0.035 0.035
0.27 to 0.34 0.1 5 to 0.40 0.50 to 0.80
C 30e
0.035 0.035
0.050 0.050
0.32 to 0.39 O. 15 to 0.40 0.50 to 0.80
1 1
0.035 0.035
aoso 0.050
0.37 to 0.44 O. 1 5 to 0.40 0.50 to 0.80
0.035
0.035
0.050 0.050
0.42 to 0.50 0.1 5 to 0.40 0.50 to 0.80
I C c45 45 e 0.035 0.035
c 50
0.050 0.050
0.47 to 0.55 O. 15 to 0.40 0.60 to 0.90
1 C5ûe
0.035 0.035
--
0.050 0.050
0.52 to 0.60 0.1 5 to 0.40 0.60 to 0.90
0.035 0.035
0.050 0.050
0.57 to 0.65 0.15 to 0.40 0.60 to 0.90
tz C 60e
0.035 0.035
*
Elements not quoted in Table 2 should not be intentionally added to the steel without the agreement of the
purchaser, other than for the purpose of finishing the heat. All reasonable precautions should be taken to pre-
vent the addition, from scrap or other materials used in manufacture, of such elements which affect the
kardenability, mechanical properties and applicability.
If ordered to condition of delivery type 1 or l(a) (see Table l), the following permis-
2.2.2.1
sible deviations between the values specified in Table 2 and the product analysis of
products up to 160 mm (6.3 in) diameter apply. Above 150 mm (5.9 in) square section,
the permissible deviations should be stated at the time of enquiry and order,
TABLE 3 - Permissible deviations between specifieu analysis and product analysis
Permissible deviations*
Type of steel
P S
k 0.02
C25, C25e
C30, C30e
C 35, C 35 e
+ 0.005 + 0.005
t 0.03 k 0.03 ti 0.04
C 40, C 40e
C45, C45e
C50, C50e
C 55, C 55 e
f 0.04
C60, C60e
*
means that in one cast the deviation may occur over the upper value or under the lower value of the specified
2 but not both at the same time.
range in Table
4 --
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ISO/R 683/1-1968 (1
2.2.2.2 If ordered to condition of delivery types 3, 3(a), 4, 4(a), 5 and 6, the mechanical
properties specified in Table 4 (page 7) and Table 5 (page 8) should be the governing
criteria for acceptance. In such cases, the cast analysis may deviate slightly from the
values shown in Table 2.
2.2.3 If specified, the mechanical properties should be those shown in Table 4 or Table 5.
2.2.3.1
The values apply to test pieces, taken on rounds in the direction of the metal fibre,
the axis of the test piece corresponding to that shown in Figure 1 (page IO).
2.2.3.2 For rectangular sections, the ranges for equivalent diameters are given in Figure 2
(page 11).
2.2.3.3 For other sections, the equivalent diameter should be agreed at the time of enquiry
and order.
2.2.4 The mechanical properties in the quenched and tempered conditions as given in Table 4 are
those which can be obtained for one of the conditions given below :
For a reference test bar of 16 mm diameter, taken from the product to be
(1)
delivered either by machining from a location according to Figure 1 or by forging,
and then quenched and tempered according to the temperatures and times listed
in Table 7 (page 9) (types of condition of delivery 3 and 3(a) of Table 1).
For a ruling section,* to be specified at the time of enquiry and order, which is
(2)
quenched and tempered according to the temperatures listed in Table 7 (types
of condition of delivery 4 and 4(a) of Table 1).
For location of the test bar, see clause 3.2.1.
For the product in the quenched and tempered condition of delivery (type of
(3)
condition of delivery 5 of Table 1).
For location of the t
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