Materials & grades

4135 / 34CrMo4 / SCM435 chromium-molybdenum steel: equivalents 1.7220 and 708A37

4135 is a chromium-molybdenum steel with about 0.35 % carbon, hardened and tempered for crankshafts, axles and other highly stressed parts. Its equivalents are 34CrMo4 (1.7220) in Europe and SCM435 in Japan, each with slightly different manganese and chromium limits.

Names by standard

What it is called in each region

RegionSystemDesignationNormaMatch
USAAISI/SAE4135SAE J404; ASTM A29 (bar)Same material
UNSG41350—Same material
UKBS 970708A37Listed against 34CrMo4 and SAE 4135 by Saarstahl. BS 970 is withdrawn in favour of European standards.BS 970-1:1991Closest equivalent
BS 970 (1955 EN series)EN19BSuperseded 1955 name that Roymech's EN table gives for 708A37. The better-known EN19 is 4140 and has its own page.—Closest equivalent
EUEN 10027-1 name34CrMo4Carbon 0.30–0.37 %, manganese 0.60–0.90 %. Same name was used in the superseded DIN 17200.EN 10083-3; EN ISO 683-2Equivalent
EN 10027-2 number1.7220EN 10083-3Equivalent
EN 10027-1 name34CrMoS4 (1.7226)Resulphurised version with sulphur controlled to 0.020–0.040 % for better machinability.EN 10083-3Closest equivalent
ÍndiaIS 11169 (Part 1)35Cr4Mo2Cold-heading and cold-extrusion steel standard. Its cross-reference annex marks 35Cr4Mo2 as identical to SAE 4135 (and lists SCM435); the limits equal SAE 4135 except phosphorus ≤0.030 %.IS 11169 (Part 1):2022Equivalent
IS 11169 (Part 1)34Cr4Mo2Cold-heading steel with the 34CrMo4 limits (C 0.30–0.37 %, Mn 0.60–0.90 %, Cr 0.90–1.20 %, Mo 0.15–0.30 %); the standard's annex lists it against EN 34CrMo4 and JIS SCM435.IS 11169 (Part 1):2022Equivalent
JapanJIS G 4053SCM435JIS G 4053Equivalent

On equivalence

  • 34CrMo4 spans the carbon of both 4130 and 4135 (0.30–0.37 %). Saarstahl, AZoM and Total Materia list 4135 against it; Ovako describes 4130 as the nearest ASTM A29 grade. Check the carbon and strength you need before substituting either way.
  • Saarstahl lists both SAE 4135 and 4137 against 34CrMo4, so some charts give 4137 as the match.
  • SCM435 and 34CrMo4 both allow 0.60–0.90 % manganese and 0.90–1.20 % chromium, against 4135's 0.70–0.90 % and 0.80–1.10 %. Kobelco's JIS G 4053 table (2008 revision) gives the Japanese limits used here. Older JIS editions printed manganese 0.60–0.85 %, and the 2023 edition could not be read.
  • 708A37 and EN19B come from Saarstahl's cross-reference and Roymech's EN table. No UK composition limits are given because no standard or mill source for 708A37 was found. UK buyers now order 34CrMo4 to EN ISO 683-2.
  • IS 11169 (Part 1):2022, the cold-heading steel standard, lists 35Cr4Mo2 with limits equal to SAE 4135 (phosphorus ≤0.030 %) and marks it identical to SAE 4135 in its cross-reference annex. IS 1570 (Part 4) has no 35Cr4Mo2. The Indian 34Cr4Mo2 in the same standard has the 34CrMo4 limits.

Chemical composition

Composition limits, mass %

Element4135USA · ASTM A29 / SAE J404 (bar)34CrMo4 (1.7220)EU · EN 10083-3 (heat analysis)35Cr4Mo2Índia · IS 11169 (Part 1):2022 (ladle analysis)SCM435Japan · JIS G 4053
C0.33–0.380.30–0.370.33–0.380.33–0.38
Si0.15–0.35≤0.400.15–0.350.15–0.35
Mn0.70–0.900.60–0.900.70–0.900.60–0.90
P≤0.035≤0.025≤0.030≤0.030
S≤0.040≤0.035≤0.040≤0.030
Cr0.80–1.100.90–1.200.80–1.100.90–1.20
Ni——≤0.25≤0.25
Mo0.15–0.250.15–0.300.15–0.250.15–0.30
Cu——≤0.35—

Mechanical properties

Strength and hardness

ConditionTensile strengthYield strengthElongationHardness
Quenched and tempered (+QT)Specified, diameter under 16 mm; yield and elongation are minimumsEN 10083-3, 34CrMo4, via Saarstahl datasheet1000–1200 MPa145–174 ksi≥800 MPa≥116 ksi≥11 %—
Quenched and tempered (+QT)Specified, diameter 16–40 mm; yield and elongation are minimumsEN 10083-3, 34CrMo4, via Saarstahl datasheet900–1100 MPa131–160 ksi≥650 MPa≥94 ksi≥12 %—
Quenched and tempered (+QT)Specified, diameter 40–100 mm; yield and elongation are minimumsEN 10083-3, 34CrMo4, via Saarstahl datasheet800–950 MPa116–138 ksi≥550 MPa≥80 ksi≥14 %—
Quenched and tempered (+QT)Specified, diameter 100–160 mm; yield and elongation are minimumsEN 10083-3, 34CrMo4, via Saarstahl datasheet750–900 MPa109–131 ksi≥500 MPa≥73 ksi≥15 %—
Quenched and tempered (+QT)Specified, diameter 160–250 mm; yield and elongation are minimumsEN 10083-3, 34CrMo4, via Saarstahl datasheet700–850 MPa102–123 ksi≥450 MPa≥65 ksi≥15 %—
Soft annealed (+A), 34CrMo4Specified maximum hardnessSaarstahl 34CrMo4 datasheet———≤223 HB
Annealed and cold drawn (4135)Hardness range only; the source gives no strength valuesAZoM, AISI 4135 alloy steel (UNS G41350)———187–229 HB

In practice

Behaviour, heat treatment and uses

Characteristics

  • Carbon sits between 4130 and 4140, so strength after quenching and tempering falls between the two. Saarstahl quotes 800–1100 MPa tensile for 34CrMo4.
  • Ovako gives maximum carbon equivalents of CEV 0.73 and Pcm 0.46 for 34CrMo4 to EN 10083-3, against 0.65 and 0.42 for 4130 to ASTM A29, so welding needs preheat and low-hydrogen practice.
  • Machinability is rated 70 % of free-cutting 1212 in the annealed or cold-drawn condition (AZoM).
  • Saarstahl lists 34CrMo4 for automotive and aircraft parts that need high toughness at high strength.

Heat treatment

  • Forging or hot rolling: 1100–850 °C (2010–1560 °F) (Saarstahl, 34CrMo4).
  • Normalizing: 850–880 °C (1560–1615 °F), cool in air (Saarstahl).
  • Soft annealing: 680–720 °C (1255–1330 °F), furnace cool (Saarstahl).
  • Hardening: 830–870 °C (1525–1600 °F) in oil or water (Saarstahl).
  • Tempering: 540–680 °C (1005–1255 °F) for the EN quenched-and-tempered conditions (Saarstahl).

Usos típicos

  • Crankshafts
  • Axles and steering knuckles
  • Railway tyres
  • Highly stressed automotive and aircraft parts

Alloy and case-hardening steels

Similar grades compared

GrauC %Mn %Cr %Ni %Tensile, first listed condition
4135 / 34CrMo40.33–0.380.70–0.900.80–1.10≤0.251000–1200 MPa
4130 / 25CrMo40.28–0.330.40–0.600.80–1.10≤0.25590–760 MPa
4140 / 42CrMo40.38–0.430.75–1.000.80–1.10≤0.25655 MPa
4340 / EN240.38–0.430.60–0.800.70–0.901.65–2.00745 MPa
5140 / 41Cr40.38–0.430.70–0.900.70–0.90≤0.25570 MPa
6150 / 51CrV40.48–0.530.70–0.900.80–1.10≤0.40670 MPa
16MnCr50.13–0.180.70–0.900.70–0.90≤0.25≥1000 MPa
20MnCr50.17–0.220.70–0.900.70–0.90≤0.25≥1200 MPa
655M13 / EN36A0.08–0.130.45–0.651.00–1.403.00–3.50700–770 MPa
8620 / 20NiCrMo2-20.18–0.230.70–0.900.40–0.600.40–0.70530 MPa

Composition from the US standard where one exists, otherwise the first standard listed on each grade's page. Strength conditions differ between grades; open a grade for its full table.

Perguntas respondidas

Common questions

What is the equivalent of 4135 steel?

34CrMo4 (1.7220) in Europe and SCM435 in Japan are the usual equivalents. The British BS 970 name is 708A37, and the nearest Indian grade is 35Cr4Mo2. All are close, not identical, to 4135.

Is 4135 the same as 34CrMo4?

They are close equivalents. 4135 has 0.33–0.38 % carbon and 0.70–0.90 % manganese; 34CrMo4 has 0.30–0.37 % carbon and 0.60–0.90 % manganese. Chromium and molybdenum overlap.

What is the difference between 4135 and 4140?

4140 has more carbon (0.38–0.43 % against 0.33–0.38 %) and slightly more manganese (0.75–1.00 % against 0.70–0.90 %). Chromium and molybdenum are the same. 4140 reaches higher strength and hardness.

Is 4135 the same as 4130?

No. 4130 has 0.28–0.33 % carbon and 0.40–0.60 % manganese, so it is lower in strength and easier to weld. 34CrMo4 covers both carbon ranges, which is why some charts list it against 4130.

Is SCM435 equivalent to 4135?

Yes, as a close equivalent. SCM435 has the same 0.33–0.38 % carbon, with 0.60–0.90 % manganese and 0.90–1.20 % chromium under JIS G 4053.

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References

Sources

  1. Saarstahl material specification sheet: 34CrMo4 / 34CrMoS4 (1.7220 / 1.7226) — +QT properties by diameter, heat treatment, BS 708A37 and SAE 4135 / 4137 cross-reference.
  2. Ovako Steel Navigator: 34CrMo4 — EN composition, ASTM A29 4130 comparison, weldability indices.
  3. Kobelco: Wire rods and bars specification tables (JIS G 4053) — SCM435 composition from the JIS G 4053 table (2008 revision).
  4. AZoM: AISI 4135 alloy steel (UNS G41350) — Composition, hardness, machinability, other designations.
  5. Wikipedia: 41xx steel (SAE composition table citing the Central Steel & Wire catalog) — SAE 4135 bar composition.
  6. Total Materia: IS 35Cr4Mo2 — Indian designation under IS 11169 (Part 1):2022 with SAE 4135 cross-reference; only C and Cr visible.
  7. Roymech: Strength of steel, BS 970 / EN equivalents table — EN19B and 708A37 against 1.7220.
  8. ICAST: EN 10083-3 34CrMo4 datasheet — EN composition cross-check.
  9. Bureau of Indian Standards, IS 11169 (Part 1):2022 Steels for cold heading and cold extrusion, wrought carbon and alloy steels (Public.Resource.Org copy) — Table C.2 ladle-analysis limits for 34Cr4Mo2 and 35Cr4Mo2; Table E.1 cross-reference to SAE 4135 and JIS SCM435.

Values summarize published limits and typical data. The governing standard and the current edition control; check them before specifying.