IS 3431:1982 50Cr4V2 Steel: Specifications & Listings
IS 3431:1982 50Cr4V2: Hot-rolled chromium-vanadium spring steel 50Cr4V2 to IS 3431:1982 as amended (Amendments 1 to 3), supplied as bars (also centreless ground or precision bars) and flats for volute, helical and laminated springs for automotive suspension. It through-hardens to at least 54 HRC in oil up to 25 mm round or 16 mm flat, and in the quenched and tempered condition reaches 1370 to 1620 MPa tensile strength. The standard was reaffirmed in 1997 and 2001.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Cr
Mn
P
S
Si
V
0.45-0.55
0.90-1.20
0.50-0.80
<=0.045
<=0.045
0.15-0.35
0.15-0.30
Mechanical Properties
Core Hardness After Quenching
>=54 HRC (oil, up to 25 mm round / 16 mm flat)
Elongation (quenched and tempered)
>=6%
Hardness, soft annealed
<=245 HB
Hardness, untreated (hot rolled)
above 310 HB (reference value)
Tensile Strength (quenched and tempered)
1370-1620 MPa
Yield Stress (quenched and tempered)
>=1180 MPa
Typical Available Sizes
Round Bar
10-100 mm
Flat Bar
20-100 mm
Sizes are indicative. Contact seller for exact availability.
More data from IS 3431:1982
From the standard
Other composition limitsfrom the table notes and clauses
Values
Maximum unless a range is given (ladle analysis)
Product analysis, permitted variation over the limit
C plus or minus 0.03, Mn plus or minus 0.04, Si plus or minus 0.03, S +0.005, P +0.005, Cr plus or minus 0.03, V plus or minus 0.02 percent
Product analysis rule
The variation does not apply both over and under the limits in several determinations in one heat
Steel making
Method left to the manufacturer or as agreed with the purchaser (Amendment No. 3)
Reduction ratio, minimum
16 to 1 from the ingot or continuous cast billet to the product; other ratios by agreement
Ladle analysis by IS 228 or another established method; the IS 228 method is the referee method.
Source: IS 3431:1982 with Amendments 1 to 3, Table 1, clauses 4 and 5
Hardness by condition2 conditions
Untreated (hot rolled), reference value
above 310 HB
Soft annealed, maximum
245 HB
The untreated values are reference values and are not binding (clause 8.1, Amendment No. 2). The soft annealed maximum is guaranteed in modes of delivery 1a and 3a (clause 8.2); it is determined on pieces carefully heated and held at 640 to 680 deg C for a time agreed between purchaser and manufacturer (Amendment No. 3). Hardness is tested to IS 1500 (Part 1).
Source: IS 3431:1982 with Amendments 1 to 3, Table 4, clauses 8.1 to 8.3.1
Quenched and tempered properties (reference specimen)modes 3, 3a and 11k
Yield stress, minimum
1180 MPa
Tensile strength
1370 to 1620 MPa
Elongation, minimum (gauge length 5.65 times the square root of S0)
6 percent
Quenching temperature
830 to 860 deg C
Tempering temperature
350 to 550 deg C
Test specimen
10 mm diameter, from the core in the rolling direction (the largest possible if 10 mm cannot be prepared)
Guaranteed in modes of delivery 3, 3a and 11k (clause 8.3). Tensile properties are tested to IS 1608 (Part 1).
Source: IS 3431:1982 with Amendments 1 to 3, Table 4, clause 8.3
Through hardenability (core hardness after quenching)guaranteed in every mode
Minimum core hardness (full through-hardening)
54 HRC
Hardened in
Oil
Quenching temperature
830 to 860 deg C
Maximum flat thickness
16 mm
Maximum round diameter
25 mm
Guaranteed in every mode of delivery for sections up to these sizes (clause 7.1). Test: a specimen not less than 2d long (d the diameter or thickness) is hardened as above and cut in two across its length; HRC is measured in the middle of the cut face to IS 1586 (Part 1) (clause 7.1.2, Amendment No. 3).
Source: IS 3431:1982 with Amendments 1 to 3, Table 3, clause 7.1
Modes of delivery (guarantee coverage)6 modes
Guarantee
1
1a
3
3a
111
11k
Chemical composition
X
X
X
X
X
X
Hardness in the core after quenching
X
X
X
X
X
X
Hardness in the soft annealed condition (G)
-
X
-
X
-
-
Cold shearability (C)
-
-
-
-
X
X
Mechanical properties, quenched and tempered, from the reference specimen
-
-
X
X
-
X
X means the property is guaranteed in that mode. Mode headings are as printed in Table 2. Steel is supplied as rolled and may also be supplied in one of these modes; delivery is usually untreated (hot rolled) with chemical composition and through-hardenability guaranteed (clauses 6.1 and 6.1.1). Cold shearability can be ordered for all grades and is recommended where the as-rolled hardness may exceed 280 HB and cold shearing is planned (clause 9.1).
Source: IS 3431:1982 with Amendments 1 to 3, Table 2, clauses 6 and 9