EN 10083-1:1991 3C55 Steel: Specifications & Listings
EN 10083-1:1991 3C55: A higher carbon special steel for quenching and tempering to EN 10083-1:1991 (printed 3 C 55), with controlled sulphur of 0.020 to 0.040% for better machinability. Supplied as semi-finished products, bars, rod, wide flats, hot rolled strip, sheet and plate, and forgings. Quenched and tempered tensile strength 800 to 950 MPa for ruling sections up to 16 mm.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Cr
Cr+Mo+Ni
Mn
Mo
Ni
P
S
Si
0.52-0.60
<=0.40
<=0.63
0.60-0.90
<=0.10
<=0.40
<=0.035
0.020-0.040
<=0.40
Mechanical Properties
Condition
Quenched and tempered, ruling section d <= 16 mm
Elongation
12% min
Hardness
Soft annealed: 229 HB max
Tensile Strength
800 to 950 MPa
Yield Strength
550 MPa min
More data from EN 10083-1:1991
From the standard
Other composition limitsTable III and its notes
Designation as printed
3 C 55
Pair grade
2C55 has the same limits except sulphur, max. 0.035
Availability
Printed in brackets: introduced partly for the first time in this standard and not available from stock in all countries (Table III, note 6)
Improved machinability
Steels with lead or higher sulphur, up to about 0.100% S, may be supplied on request (Table III, note 3)
Restricted options
Without hardenability or quenched and tempered or normalized property requirements, a carbon range of 0.05 and/or Cr + Mo + Ni below 0.45 may be agreed (Table III, note 5)
Elements not quoted in Table III are not intentionally added without the purchaser's agreement, other than for finishing the heat. With hardenability requirements, slight deviations within Table IV are permitted except for carbon, phosphorus and sulphur.
Source: EN 10083-1:1991 (UNI EN 10083-1), Table III and its notes
Mechanical properties, quenched and tempered3 sections
Ruling section
Yield strength Re, min (MPa)
Tensile strength Rm (MPa)
Elongation A, min (%)
Reduction of area Z, min (%)
Impact KV, min (J)
d <= 16 mm, t <= 8 mm
550
800 to 950
12
30
-
16 mm < d <= 40 mm, 8 mm < t <= 20 mm
490
750 to 900
14
35
-
40 mm < d <= 100 mm, 20 mm < t <= 60 mm
420
700 to 850
15
40
-
Re is the upper yield strength or, if no yield phenomenon occurs, the 0.2% proof strength; A on gauge length 5.65 times the root of the original cross section; KV on longitudinal ISO V-notch test pieces, average of 3 values, no single value below 70% of the minimum. Ruling sections as in Appendix B. Sizes not listed are not covered by the standard.
Source: EN 10083-1:1991 (UNI EN 10083-1), Table IX
Mechanical properties, normalized3 sizes
Size
Yield strength Re, min (MPa)
Tensile strength Rm, min (MPa)
Elongation A, min (%)
d <= 16 mm, t <= 16 mm
370
680
11
16 mm < d <= 100 mm, 16 mm < t <= 100 mm
330
640
12
100 mm < d <= 250 mm, 100 mm < t <= 250 mm
300
620
12
Values also apply to the grades with hardenability requirements (H, HH, HL). Sizes not listed are not covered by the standard.
Source: EN 10083-1:1991 (UNI EN 10083-1), Table X
Maximum hardness by delivery conditionTable VIII
Treated to improve shearability (TS), max
255 HB
Soft annealed (TA), max
229 HB
Values also apply to the grades with hardenability requirements (H, HH, HL); not applicable to continuously cast slabs not further deformed. Depending on the cast and the dimensions, particularly for HH grades, soft annealing may be necessary.
Source: EN 10083-1:1991 (UNI EN 10083-1), Table VIII
Hardenability, end quench test (H)Hardness band
Hardness band (HRC, minimum to maximum) by distance from the quenched end (mm)
1
2
3
4
5
6
7
8
9
10
11
13
15
20
25
30
Distance from quenched end (mm)
1
2
3
4
5
6
7
8
9
10
11
13
15
20
25
30
Maximum, HRC
65
64
63
62
60
57
52
45
37
36
35
34
33
32
30
29
Minimum, HRC
58
55
47
37
33
32
31
30
29
28
27
26
25
24
22
20
Applies when ordered as 3C55 H. Provisional values for non alloy steels; a manufacturer whose band falls outside these limits informs the purchaser at ordering (Table V, note 1). End quench test at 830 ± 5 deg C (Table XIII).
Source: EN 10083-1:1991 (UNI EN 10083-1), Table V
Restricted hardenability (HH, HL), provisionalTable VI
Symbol
1 mm (HRC)
5 mm (HRC)
HH5
-
42 to 60
HH15
60 to 65
42 to 60
HL5
-
33 to 51
HL15
58 to 63
33 to 51
Apply to both the 2C and 3C grade. The figure after the symbol gives the distances (mm) at which the limits apply.
Source: EN 10083-1:1991 (UNI EN 10083-1), Table VI
Heat treatmentTable XIII
Quenching
805 to 845 deg C
Quenching agent
Oil or water
Tempering
550 to 660 deg C
End quench test
830 ± 5 deg C
Normalizing
825 to 865 deg C
Guidance values except the end quench test temperature, which is binding. Lower quenching temperatures generally for water, upper for oil; austenitizing at least 30 min, tempering at least 60 min (guide values).
Source: EN 10083-1:1991 (UNI EN 10083-1), Table XIII
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