IS 5517:1993 40C8 Steel: Specifications & Listings
IS 5517:1993 40C8: 40C8 is a steel in IS 5517:1993 (Steels for Hardening and Tempering), intended in general for forgings and machined parts for engineering or automobile purposes.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Si
Mn
S
P
0.35-0.45
0.10-0.35
0.60-0.90
<=0.035
<=0.035
Mechanical Properties
Tensile Strength
600-750 MPa
Yield Strength (0.2% proof)
380 MPa min
Elongation
>=18%
Izod Impact
41 J min
Hardness (annealed)
<=207 HB
Condition
Hardened and tempered, ruling section up to 63 mm
Typical Available Sizes
Round Bar
16-350 mm dia
Flat Bar
25-200 mm width
Sizes are indicative. Contact seller for exact availability.
More data from IS 5517:1993
From the standard
Heat treatment temperatures5 values
Hot working temperature
1200 to 850 °C
Normalising temperature
830 to 860 °C
Hardening temperature
830 to 860 °C
Quenching medium
Water or Oil
Tempering temperature
550 to 660 °C
Source: IS 5517:1993 with Amendments 1 to 3, Table 4
Properties after hardening and tempering, by ruling section2 sections
Tensile strength (MPa)
0.2% proof stress, min (MPa)
Elongation, min (%)
Izod impact, min (J)
Limiting ruling section (mm)
600 to 750
380
18
41
63
700 to 850
480
17
35
30
Values apply to test bars taken from rounds along the direction of rolling. Izod impact values are for fine grained steels.
Source: IS 5517:1993 with Amendments 1 to 3, Table 5
Hardness by delivery condition3 conditions
As annealed (A), maximum
207 HB
As rolled (R), maximum
240 HB
Treated for improved machinability (M), maximum
197 HB
For improved machinability the microstructure of the steel may be mutually agreed between the manufacturer and the purchaser.
Source: IS 5517:1993 with Amendments 1 to 3, Table 6