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GV SteelsEstablished 2008
Resources/Materials & grades/1045 / C45

Materials & grades

1045 / C45 / S45C medium-carbon steel: equivalents 45C8, 080M46 (EN43B) and Ck45

1045 is a medium-carbon steel with about 0.45 % carbon, supplied hot rolled, normalized or quenched and tempered for shafts, pins, gears and forgings. Its close equivalents are C45 (1.0503) in Europe, 080M46 (old EN43B) in the UK, 45C8 in India and S45C in Japan, each with slightly different composition limits.

Names by standard

What it is called in each region

RegionSystemDesignationStandardMatch
USAAISI/SAE1045SAE J403; ASTM A29 / A108Same material
UNSG10450—Same material
UKBS 970080M46Listed against 1045 and C45 by Interlloy, Saarstahl and Applus. BS 970 has been withdrawn in favor of European standards.BS 970-1:1972Closest equivalent
BS 970080A47Composition-specified variant listed by Interlloy for 1045.BS 970-3:1991Closest equivalent
BS 970 legacy EN seriesEN43Bsuperseded name listed by Interlloy for 1045.—Closest equivalent
BS 970 legacy EN seriesEN8D (080A42)Superseded name. 0.40–0.45 % C, between 1040 and 1045; sometimes offered as a 1045 substitute.—Closest equivalent
EUEN 10027-1 nameC45Carbon 0.42–0.50 %, manganese 0.50–0.80 %.EN ISO 683-1 (formerly EN 10083-2)Equivalent
EN 10027-2 number1.0503Material number of C45.EN ISO 683-1Equivalent
EN 10027-1 nameC45E (1.1191) / C45R (1.1201)Variants with tighter phosphorus and sulfur (E) or a controlled sulfur range (R).EN ISO 683-1Equivalent
DIN (legacy)Ck45 / Cm45Superseded German names for C45E and C45R. Ck45 is still widely searched.—Equivalent
IndiaIS 157045C8Carbon 0.40–0.50 %, manganese 0.60–0.90 %.IS 1570 (Part 2/Sec 1)Closest equivalent
IS 1570 (old designation)C45Superseded Indian name for 45C8.—Closest equivalent
JapanJIS G 4051S45CCarbon 0.42–0.48 %, a narrower range than 1045.JIS G 4051Closest equivalent

On equivalence

  • 1045 and C45 are close equivalents, not the same specification: C45 allows 0.42 % minimum carbon and 0.50–0.80 % manganese against 1045's 0.43–0.50 % C and 0.60–0.90 % Mn. EN ISO 683-1 also specifies mechanical properties by condition and size.
  • UK sources disagree on the British name. Interlloy lists 080M46 (BS 970-1:1972), 080A47 (BS 970-3:1991) and EN43B (legacy); Saarstahl and Applus list 080M46; Ovako lists 080A42; some suppliers offer EN8D (080A42). 080M46 is the most consistently cited.
  • EN8 (080M40) is a lower-carbon grade matching 1040, not 1045.
  • S45C has a narrower carbon range (0.42–0.48 %) than 1045. The full S45C composition here combines Total Materia's JIS G 4051:2023 carbon, chromium and nickel limits with silicon, manganese, phosphorus and sulfur limits from a secondary source.
  • Indian 45C8 under IS 1570 fixes only carbon and manganese; phosphorus, sulfur and silicon come from the product standard ordered.

Chemical composition

Composition limits, mass %

Element1045USA · SAE J403080A42 (EN8D)UK · BS 970C45 (1.0503)EU · EN 10083-2 / EN ISO 683-1C45E (1.1191)EU · EN 10083-2 / EN ISO 683-145C8India · IS 1570 (Part 2/Sec 1):1979S45CJapan · JIS G 4051
C0.43–0.500.40–0.450.42–0.500.42–0.500.40–0.500.42–0.48
Si—0.10–0.40≤0.40≤0.40—0.15–0.35
Mn0.60–0.900.70–0.900.50–0.800.50–0.800.60–0.900.60–0.90
P≤0.030≤0.050≤0.045≤0.030—≤0.030
S≤0.050≤0.050≤0.045≤0.035—≤0.035
Cr——≤0.40≤0.40—≤0.20
Ni——≤0.40≤0.40——
Mo——≤0.10≤0.10——
Cr+Mo+Ni——≤0.63≤0.63——
Cr+Ni—————≤0.35

Mechanical properties

Strength and hardness

ConditionTensile strengthYield strengthElongationHardness
Hot rolled (1045)Estimated minimum, bars 19–32 mm (3/4–1-1/4 in), SAE J1397 basisSAE J1397 estimates as published by ICAST and AZoM82 ksi (565 MPa)45 ksi (310 MPa)16 %163 HB
Cold drawn (1045)Estimated minimum, bars 19–32 mm (3/4–1-1/4 in), SAE J1397 basisSAE J1397 estimates as published by ICAST91 ksi (630 MPa)77 ksi (530 MPa)12 %179 HB
Normalized (1045)Typical values, not minimumsInterlloy 1045 datasheet93 ksi (640 MPa)59 ksi (410 MPa)22 %187 HB
Normalized +N (C45 / C45E)Specified minimum, d 16–100 mmEN 10083-2 as tabulated by Roymech and Saarstahl≥84 ksi (≥580 MPa)≥44 ksi (≥305 MPa)16 %—
Quenched and tempered +QT (C45 / C45E)Specified, d 16–40 mmEN 10083-2 as tabulated by Roymech and Saarstahl94–116 ksi (650–800 MPa)≥62 ksi (≥430 MPa)16 %—
Hot rolled or normalized (45C8)Specified range, ruling sections up to 150 mmIS 1570 (Part 2/Sec 1):1979, Table 291–103 ksi (630–710 MPa)—15 %—
Hardened and tempered (45C8)Specified, limiting ruling section 30 mmIS 1570 (Part 2/Sec 1):1979, Table 4102–123 ksi (700–850 MPa)≥69.6 ksi (≥480 MPa)15 %—

In practice

Behavior, heat treatment and uses

Characteristics

  • Higher strength and wear resistance than low-carbon steels, with fair toughness in the normalized condition.
  • Low hardenability: Interlloy recommends through hardening only for sections up to about 60 mm.
  • Flame or induction hardening gives surface hardness of about 54–60 HRC over an unchanged core (Interlloy).
  • Does not respond well to nitriding because it lacks nitride-forming alloying elements.
  • Weldable in the hot-rolled or normalized condition with preheat, low-hydrogen electrodes and stress relief; welding in the hardened condition is not recommended.
  • Good machinability in the hot-rolled or normalized condition.

Heat treatment

  • Forging: about 1100–1200 °C (2010–2190 °F), finishing no lower than about 850 °C (1560 °F) (Interlloy).
  • Normalizing: about 840–880 °C (1545–1615 °F) (Saarstahl, C45) or 870–920 °C (1600–1690 °F) (Interlloy, 1045), cool in still air.
  • Annealing: about 800–850 °C (1470–1560 °F), furnace cool (Interlloy); soft annealing about 680–710 °C (1255–1310 °F) (Saarstahl).
  • Hardening: about 820–850 °C (1510–1560 °F) with a water quench, or 830–860 °C (1525–1580 °F) with an oil quench (Interlloy).
  • Tempering: about 400–650 °C (750–1200 °F) depending on the strength required; Saarstahl gives 550–660 °C (1020–1220 °F) for +QT.
  • Stress relieving: about 550–660 °C (1020–1220 °F), then cool in still air (Interlloy).

Typical uses

  • Shafts, axles and spindles
  • Pins, studs and bolts
  • Gears, sprockets and rolls that are flame or induction hardened
  • Connecting rods and hydraulic clamps and rams
  • General forgings and machined components

Carbon steels

Similar grades compared

GradeC %Mn %Cr %Ni %Tensile strength, first listed condition
1045 / C450.43–0.500.60–0.90≤0.40≤0.4082 ksi (565 MPa)
1030 / C300.28–0.340.60–0.90≤0.40≤0.4068 ksi (470 MPa)
1035 / C350.32–0.380.60–0.90≤0.40≤0.4073 ksi (500 MPa)
1040 / C40 / EN80.37–0.440.60–0.90≤0.40≤0.4076 ksi (524 MPa)
1050 / C500.48–0.550.60–0.90≤0.40≤0.4090 ksi (620 MPa)
1055 / C550.50–0.600.60–0.90≤0.40≤0.4094 ksi (650 MPa)
1008≤0.100.30–0.50——44 ksi (303 MPa)
1010 / C10E0.08–0.130.30–0.60≤0.30—46 ksi (320 MPa)
1015 / C15E0.13–0.180.30–0.60≤0.30—49 ksi (340 MPa)
10180.15–0.200.60–0.90≤0.20—58 ksi (400 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's page for its full table.

Questions answered

Common questions

Is 1045 the same as C45?

They are close equivalents and are often substituted, but not identical. C45 (1.0503) has 0.42–0.50 % carbon and 0.50–0.80 % manganese; 1045 has 0.43–0.50 % carbon and 0.60–0.90 % manganese.

What is the British equivalent of 1045?

080M46 under BS 970 is the name most sources give. Older names include EN43B, and EN8D (080A42) is sometimes offered as a near substitute. BS 970 has been withdrawn, and UK buyers now usually order C45 to EN ISO 683-1.

What is the difference between C45 and Ck45?

Ck45 is the old German DIN name for C45E (1.1191). It has the same carbon and manganese as C45 but tighter phosphorus and sulfur limits (≤0.030 % P and ≤0.035 % S instead of ≤0.045 % each).

Is S45C equivalent to 1045?

Yes, as a close equivalent. S45C (JIS G 4051) has 0.42–0.48 % carbon and 0.60–0.90 % manganese, so it falls within or very near the 1045 limits.

Can 1045 be induction hardened?

Yes. Flame or induction hardening of normalized 1045 gives a surface hardness of about 54–60 HRC, depending on quench and section. The core keeps its supplied properties.

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Keep reading

1040 / C40 / EN81040, C40, EN8 (080M40), 40C8 and S40C are closely related medium-carbon steels with about 0.40 % carbon, used for shafts, axles, studs and forgings that need more strength than mild steel.4140 / 42CrMo4AISI 4140 is a medium-carbon chromium-molybdenum alloy steel, normally used hardened and tempered for shafts, gears and high-strength bolts.10181018 is a low-carbon, non-alloy steel with 0.15–0.20 % carbon and 0.60–0.90 % manganese, widely used as cold-drawn bar for machined and case-hardened parts.NormalizingNormalizing heats steel above its upper critical temperature and lets it cool in still air to give a fine, uniform ferrite–pearlite structure.Quenching and temperingQuenching and tempering hardens steel by cooling it rapidly from the austenite range to form martensite, then reheats it below Ac1 to trade some hardness for toughness.AnnealingAnnealing heats steel to a set temperature, holds it and cools it slowly to make it softer, more ductile and easier to machine or cold form.SAE / AISI numbersA four-digit SAE/AISI number such as 1045 or 4140 names a carbon or alloy steel by its chemistry: the first two digits identify the steel family and the last two give the nominal carbon content in hundredths of a percent.EN 10027 names and numbersEuropean steels carry two identifiers under EN 10027: a steel name (Part 1) such as S235JR, C45 or 42CrMo4 that describes the steel's use or chemistry, and a material number (Part 2) such as 1.0503 or 1.7225.BS 970 and the EN seriesBS 970 names steels with a six-character code such as 080M40, in which the first three digits give the steel type, the letter says how the steel is specified and the last two digits give the carbon content.IS 1570 and Indian designationsIndian steel names follow the letter-symbol code in IS 1762 (Part 1), which the IS 1570 schedules use: 45C8 means about 0.45% carbon, C for carbon steel and about 0.8% manganese, while alloy names such as 40Cr4Mo3 list each element with a multiplied content figure.JIS steel designationsJapanese JIS steel symbols start with S for steel and add letters for the steel family or its use, but the number means different things in different standards.

References

Sources

  1. ICAST: SAE J403 / SAE J1397 UNS G10450, Hot Rolled — SAE J403 composition and J1397 estimated properties.
  2. ICAST: SAE J403 / SAE J1397 UNS G10450, Cold Drawn
  3. AZoM: AISI 1045 Medium Carbon Steel
  4. Interlloy: 1045 medium tensile carbon steel bar — Related specifications (080M46, 080A47, EN43B, S45C, UNS G10450), typical properties and heat treatment.
  5. Roymech: EN 10083 steels for quenching and tempering — C45 / C45E composition and +N / +QT properties.
  6. Saarstahl material specification sheet: C45 (1.0503) — Composition, heat treatment and properties; lists BS 080M46 and SAE 1045.
  7. Ovako Steel Navigator: C45 — Lists similar designations including Ck45, 080A42, S 45 C and 1045.
  8. Applus+ Laboratories: C45 / 1.0503 datasheet — Cross-reference to BS 970/1 080M46 and ASTM A576 1045.
  9. Macsteel: Bright bar 080A42 (EN8D)
  10. IS 1570 (Part 2/Sec 1):1979 Schedules for wrought steels: carbon steels (public copy)
  11. Total Materia: JIS S45C (JIS G 4051:2023) — C, Cr and Cr+Ni limits.
  12. Rapid Protos: S45C carbon steel — Si, Mn, P and S limits for S45C. Secondary source; the page is internally inconsistent on carbon.
  13. MISUMI: JIS and foreign standards comparison for machine structural steels

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