Steel Standart

C45 equivalent grades: ASTM, EN, JIS, GB, DIN

C45 is medium-carbon steel for quenching and tempering specified in EN 10083-2. The cross-reference runs across 5 standard systems and grades every candidate, so the reason a substitution is safe is on the same row as the name. The full C45 data sheet carries the composition and mechanical tables.

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Mills routinely dual-certify C45 as 1045, 45, S45C — the limits sit inside each other in both directions. 080M46, 080M40, C45E differ by one requirement, which is a line on the order rather than a redesign. Functionally interchangeable, 42CrMo4 serves a different route to the same duty — check the design, not the analysis. Across systems that is 1 in AISI / SAE, 1 in GOST (Russia/CIS), 1 in JIS (Japan), 2 in BS (superseded British), 2 in EN (European).

Cross-reference table

C45 equivalents by system
GradeSystemMatchWhy / differences
1045AISI / SAEIdenticalAISI/SAE 1045 (UNS G10450): C 0.43–0.50, Mn 0.60–0.90 — same carbon window; C45 additionally caps Cr/Mo/Ni. Interchangeable in practice.
45GOST (Russia/CIS)IdenticalGOST 1050 Steel 45: C 0.42–0.50, Mn 0.50–0.80, Si 0.17–0.37.
S45CJIS (Japan)IdenticalJIS G4051 S45C: C 0.42–0.48, Mn 0.60–0.90; matches C45 within rounding.
080M46BS (superseded British)NearBS 970 080M46: C 0.42–0.50, Mn 0.60–1.00 — slightly wider Mn.
080M40BS (superseded British)NearC45 (1.0503) is 0.42–0.50 % C against 080M40's 0.36–0.44 %, so it sits slightly above — closer to 080M46. For general shafting the substitution is routine, but C45 will through-harden marginally deeper and machine marginally harder.
C45EEN (European)NearSame grade with P ≤ 0.030 and guaranteed impact; order C45E when toughness or fine grain matters.
42CrMo4EN (European)FunctionalAlloyed alternative with far higher hardenability for the same part geometry above 25 mm.

Identical, near and functional are defined once on the grade index; the reason column below says which limit differs in each case.

C45 in AISI / SAE

  • 1045 — Identical AISI/SAE 1045 (UNS G10450): C 0.43–0.50, Mn 0.60–0.90 — same carbon window; C45 additionally caps Cr/Mo/Ni. Interchangeable in practice.

C45 in GOST (Russia/CIS)

  • 45 — Identical GOST 1050 Steel 45: C 0.42–0.50, Mn 0.50–0.80, Si 0.17–0.37.

C45 in JIS (Japan)

  • S45C — Identical JIS G4051 S45C: C 0.42–0.48, Mn 0.60–0.90; matches C45 within rounding.

C45 in BS (superseded British)

  • 080M46 — Near BS 970 080M46: C 0.42–0.50, Mn 0.60–1.00 — slightly wider Mn.
  • 080M40 — Near C45 (1.0503) is 0.42–0.50 % C against 080M40's 0.36–0.44 %, so it sits slightly above — closer to 080M46. For general shafting the substitution is routine, but C45 will through-harden marginally deeper and machine marginally harder.

C45 in EN (European)

  • C45E — Near Same grade with P ≤ 0.030 and guaranteed impact; order C45E when toughness or fine grain matters.
  • 42CrMo4 — Functional Alloyed alternative with far higher hardenability for the same part geometry above 25 mm.

Superseded names for C45

  • Ck45 — DIN 17200 (withdrawn 1987): Ck45 = today's C45E (1.1191). Still the most-used name in German-speaking workshops.
  • C45 (1.0503) — DIN 17200: Base quality, number unchanged.
  • 080M46 — BS 970 (withdrawn)
  • XC45 / XC48 — NF A 35-552
  • C45 / C46 — UNI 7845

Key data for C45

Yield340 MPa +N normalized, ≤ 16 mm
Tensile≥ 620 MPa
Carbon0.42 – 0.5 %
StandardEN 10083-2

Full composition, mechanical properties by thickness, heat treatment and applications for C45 →

Verified against EN 10083-2:2006. Last checked: September 2026.