Close Alternative — 79.6% match
based on chemical composition and mechanical property overlap.
IS 3431 65Si7 (IS 3431:1982) and IS 3431 55Si7 (IS 3431:1982) are both steel grades.
Both fall under the Spring Steel category.
IS 3431 65Si7 is typically used for volute, helical and laminated springs for automotive suspension; hot-rolled (also centreless ground or precision) bars and flats (clause 1.1), while IS 3431 55Si7 is commonly used for leaf springs,coil springs,automotive suspension springs,industrial springs,washer springs.
IS 3431 65Si7 is defined under Bureau of Indian Standards (IS), originating from India, while IS 3431 55Si7 is defined under Bureau of Indian Standards (IS), originating from India.
As per chemical composition, IS 3431 65Si7 vs IS 3431 55Si7 is a 91.7% match.
As per mechanical properties, the match is 55.6%.
Combined, this makes them a close alternative overall at 79.6%.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property
IS 3431 65Si7
IS 3431 55Si7
Core Hardness After Quenching
>=54 HRC (oil, up to 25 mm round / 16 mm flat)
>=54 HRC (oil, up to 20 mm round / 16 mm flat)
Elongation (quenched and tempered)
>=6%
>=6%
Hardness, soft annealed
<=255 HB
<=245 HB
Hardness, untreated (hot rolled)
about 310 HB (reference value)
about 270 HB (reference value)
Tensile Strength (quenched and tempered)
1370-1620 MPa
1320-1570 MPa
Yield Stress (quenched and tempered)
>=1180 MPa
>=1130 MPa
Typical Applications
IS 3431 65Si7
Volute, helical and laminated springs for automotive suspension; hot-rolled (also centreless ground or precision) bars and flats (clause 1.1)
Can IS 3431 65Si7 Be Substituted With IS 3431 55Si7?
IS 3431 65Si7 and IS 3431 55Si7 are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.
What is the difference between IS 3431 65Si7 and IS 3431 55Si7?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can IS 3431 65Si7 be substituted with IS 3431 55Si7?
IS 3431 65Si7 and IS 3431 55Si7 are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.