Alloy Steel Equivalent Grades in India: EN, BS 970, DIN, AISI, JIS and IS Chart

Short answer: The same alloy steel is sold under different names depending on the standard. EN24 is also 817M40, 34CrNiMo6, AISI 4340 and SNCM439; EN19 is 709M40, 42CrMo4 and AISI 4140; EN47 is 735A51 and 51CrV4. The chart below lists the common engineering and alloy steels used in India across BS 970, European/DIN, AISI/SAE, JIS and Indian Standard (IS) designations.

In this guide: Equivalent grades chart · How the naming systems work · Equivalent is not identical · How to substitute safely · What we stock · FAQ

Equivalent grades chart: EN, BS 970, DIN, AISI, JIS and IS

The first five rows are the alloy grades we stock as round bar in Mumbai; the rest are other grades buyers often ask about, listed for reference.

* Closest match only: there is no exact equivalent in that standard, and the grade shown differs in at least one alloying element. A dash means no commonly used equivalent. EN47 is also sold as 735A50. Always confirm against the full specification before substituting.

How the naming systems work

• EN numbers (EN1 to EN58) come from the original British Standard BS 970. They are still the names most Indian buyers and drawings use, even though the standard was withdrawn in 2006. Do not confuse them with modern "EN" European standards such as EN 10083 or EN 10084, which use names like 42CrMo4.
• BS 970 six-character codes such as 817M40 replaced the EN numbers in the 1970s. The first three digits give the alloy family, the letter tells you how the steel is specified (A = analysis, M = mechanical properties, H = hardenability) and the last two digits are the nominal carbon in hundredths of a percent (817M40 = 0.40% carbon).
• European / DIN names such as 34CrNiMo6 start with the carbon content in hundredths of a percent, followed by the main alloying elements. Each grade also has a material number (Werkstoff number) such as 1.6582, which is often easier to match on a certificate.
• AISI / SAE numbers such as 4340 use the first two digits for the alloy family and the last two for carbon (4340 = 0.40% carbon).
• JIS names such as SNCM439 describe the elements (S = steel, N = nickel, C = chromium, M = molybdenum) followed by a series number.
• Indian Standard (IS) names such as 40Ni2Cr1Mo28 follow IS 1762: the first number is carbon in hundredths of a percent, and each alloy element is followed by its content multiplied by a factor (4 for chromium, nickel and manganese; 10 for molybdenum and vanadium). So 50Cr4V2 means about 0.50% carbon, 1% chromium and 0.2% vanadium.

Equivalent does not always mean identical

Equivalent grades are designed for the same job, but each standard sets its own limits. The chemistry ranges usually overlap rather than match exactly, so one heat of steel can comply with two standards while another heat complies with only one. Some well-known pairs also differ in a real way:

• EN24 vs AISI 4340: very close and treated as interchangeable in most engineering work, but the manganese and nickel ranges are not identical.
• EN36C vs 655M13: 655M13 is plain EN36 without molybdenum. If the drawing says EN36C or 832M13, you need the molybdenum grade (see our EN36A vs EN36B vs EN36C guide).
• SAE 8620 vs EN353: both are case-hardening steels, but EN353 has roughly twice the nickel and more chromium, so it hardens deeper and suits larger gears and shafts.
• EN24 vs EN24T: the T is a heat-treatment condition (hardened and tempered), not a different chemistry (see our EN24 vs EN24T guide).

How to substitute an equivalent grade safely

• Check the chemistry, not just the name. Compare the mill test certificate's actual analysis with the ranges in the standard on your drawing.
• Check the condition. Annealed, as-rolled and hardened-and-tempered bars of the same grade behave very differently. Make sure the supplied condition suits your machining and heat treatment.
• Check the section size. Hardenability limits how deep a grade will harden. A grade that works at Ø40 mm may not reach the core hardness you need at Ø150 mm.
• Get the designer's approval when the drawing calls for a specific standard, especially for safety-critical or export parts.

Equivalent grades we stock in Mumbai

Sai International stocks these alloy steels as round bar at Darukhana, Mumbai:

• EN24 / 817M40: Ø16–205 mm (annealed up to Ø100 mm, as-rolled from Ø105 mm). EN24T is supplied against orders of 3–5 tons.
• EN36C / 832M13: Ø14–205 mm, as-rolled. Annealed bars are supplied against orders.
• EN353: Ø16–205 mm.
• SAE 8620: Ø14–315 mm.
• EN47 / 51CrV4: annealed, round Ø16–205 mm, plus square and flat bar.

Minimum order is 100 kg. Cutting is available if the balance piece is also taken, and is charged extra. Prices are ex-Darukhana; loading, transport and cartage are extra at actuals. Every dispatch comes with a mill test certificate. To work out bar weights before you order, use our round bar weight calculator.

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Equivalent grades: frequently asked questions

What is the equivalent of EN24 steel?

EN24 is 817M40 in BS 970. The usual equivalents are 34CrNiMo6 (material no. 1.6582) in European/DIN standards, AISI/SAE 4340 in the US, SNCM439 in Japan (JIS) and 40Ni2Cr1Mo28 in the Indian standard.

What is the equivalent of EN19 steel?

EN19 is 709M40 in BS 970. Its common equivalents are 42CrMo4 (1.7225), AISI/SAE 4140, JIS SCM440 and IS 40Cr4Mo3.

Is SAE 8620 the same as EN353?

No. Both are nickel-chromium-molybdenum case-hardening steels, but SAE 8620 (805M20, 20NiCrMo2-2) has about 0.4–0.7% nickel, while EN353 (815M17) has about 1.0–1.5% nickel and more chromium. EN353 hardens deeper and gives a tougher core in larger sections, so one should not be swapped for the other without the designer's approval.

Is EN36C equivalent to 655M13?

Not exactly. 655M13 is the modern name for plain EN36 (EN36A/EN36B), a 3% nickel-chromium steel. EN36C adds 0.10–0.25% molybdenum and is designated 832M13. Its closest European equivalent is 14NiCrMo13-4 (1.6657).

What is the Indian (IS) equivalent of EN47?

EN47 (735A51, 51CrV4) corresponds to 50Cr4V2 in the Indian designation system: about 0.5% carbon, 1% chromium and 0.2% vanadium.

Can I use an equivalent grade if my drawing names a different standard?

Usually yes, if the chemistry ranges overlap and the required mechanical properties or hardness are met in the heat-treated condition you will use. The grade on the drawing should still be confirmed by the designer, and the mill test certificate should be checked against the original specification.

Do you supply mill test certificates with equivalent grades?

Yes. Every dispatch from Sai International comes with a mill test certificate showing the actual chemistry of that heat, so you can check it against whichever standard your drawing uses.

Related: Round bar weight calculator · EN24 vs EN24T · EN36A vs EN36B vs EN36C · EN47 spring steel guide