IS 4367:1991 21Cr4Mo2 Steel: Specifications & Listings
IS 4367:1991 21Cr4Mo2: 21Cr4Mo2 is a steel in IS 4367:1991 (Alloy Steel Forgings for General Industrial Use), which covers forgings in the as forged, heat-treated or machined condition.
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
Cr
Mo
S
P
<=0.26
0.10-0.35
0.50-0.80
0.90-1.20
0.15-0.30
<=0.035
<=0.035
Mechanical Properties
Tensile Strength
650-800 MPa
Yield Strength
420 MPa min
Elongation
>=16%
Izod Impact
60 J min
Hardness
190-235 HB
Hardness (soft annealed)
<=210 HB
Condition
Hardened and tempered, ruling section up to 150 mm
More data from IS 4367:1991
From the standard
Properties by ruling section3 sections
Tensile strength (MPa)
Yield strength, min (MPa)
Elongation, min (%)
Izod impact, min (J)
Hardness (HB)
Limiting ruling section (mm)
650 to 800
420
16
60
190 to 235
150
700 to 850
460
15
55
208 to 252
100
800 to 950
580
14
50
235 to 280
40
Test condition: hardened and tempered. Maximum hardness in the soft annealed condition: 210 HB.
Source: IS 4367:1991 with Amendments 1 and 2, Table 3
Sulphur, phosphorus and aluminium limitsordering options
Option 1
Sulphur and phosphorus 0.030 max each
Option 2
Sulphur 0.020 to 0.035, phosphorus 0.035 max
Aluminium, when the steel is aluminium killed
0.02 to 0.05
The purchaser orders sulphur and phosphorus under option 1 or option 2.
Source: IS 4367:1991 with Amendments 1 and 2, Table 1, notes 1 and 2