45C8 Steel at a Glance
- Grade
- 45C8 — medium-carbon (~0.45% C) unalloyed engineering steel
- Composition
- C 0.40–0.50%, Mn 0.60–0.90%, Si 0.10–0.35%, S & P 0.050% max
- Equivalents
- AISI/SAE 1045 · C45 (1.0503) · JIS S45C · BS 080M46 / EN9
- Mechanical (normalised)
- Tensile 620–720 MPa, Yield 340–460 MPa, Hardness 180–230 HB
- Forms supplied
- Rounds, bright bars, hexagons, RCS
- Typical uses
- Shafts, axles, spindles, studs, gears, levers, forgings
What is 45C8 steel?
45C8 is a medium-carbon, unalloyed engineering steel with about 0.45% carbon, used where a component needs more strength, hardness and wear resistance than mild steel but does not justify a chrome or chrome-moly alloy.
The designation follows the Indian convention for plain-carbon steels: the figure indicates roughly 0.45% mean carbon, and the manganese sits around 0.8%. In practical terms 45C8 is the Indian name for the same steel the rest of the world calls C45, AISI 1045 or S45C. A buyer holding a drawing that calls for any of those four can be served from the same heat, provided the certified chemistry meets the tighter of the two specifications.
At this carbon level the steel responds well to normalising and to through-hardening in small to medium sections, and it takes a clean finish on a lathe or CNC. It is the default choice across Indian machine shops and forging units for general-purpose shafting, studs and pins — strong enough for moderate loads, cheaper and more available than alloy steel, and forgiving to machine. For higher fatigue loads or larger hardened sections, buyers step up to EN19 (42CrMo4) or SAE 4140.
45C8 chemical composition
Typical wrought 45C8 chemistry. Sulphur and phosphorus are residual ceilings; the heat-wise mill test certificate carries the actual ladle analysis for the bars you receive.
| Element | Range | Role |
|---|---|---|
| Carbon (C) | 0.40–0.50 | Sets strength, hardness and hardenability |
| Manganese (Mn) | 0.60–0.90 | Aids hardenability and ties up sulphur |
| Silicon (Si) | 0.10–0.35 | Deoxidiser; minor strengthening |
| Sulphur (S) | 0.050 max | Kept low for soundness and ductility |
| Phosphorus (P) | 0.050 max | Kept low to protect toughness |
Exact limits shift slightly between the governing carbon-steel standards. Confirmed values are stated on the MTC for each heat.
45C8 mechanical properties
Mechanical properties depend on section size and condition (as-rolled, normalised or quenched-and-tempered). The figures below are typical for normalised bar in common diameters; a quenched-and-tempered small section reaches higher strength and hardness. Guaranteed values are confirmed on the mill test certificate.
| Property | Typical value |
|---|---|
| Tensile strength | 620–720 MPa |
| Yield strength | 340–460 MPa |
| Elongation (A5) | 15–20% |
| Hardness | 180–230 HB |
| Hardness, Q&T small section | up to ~55 HRC achievable on the surface after hardening |
Physical properties
| Property | Typical value |
|---|---|
| Density | ~7.85 g/cm³ |
| Modulus of elasticity | ~200 GPa |
| Thermal conductivity | ~48 W/m·K (room temperature) |
| Coefficient of thermal expansion | ~11–12 ×10⁻₆/K (20–100 °C) |
| Magnetic | Yes (ferromagnetic) |
What is 45C8 equivalent to?
45C8 sits in the global 0.45% carbon family. The nearest international designations are listed below. Equivalents are close matches, not exact substitutes — when a drawing names a specific standard, order to that standard and confirm against the MTC.
| Standard | Equivalent designation |
|---|---|
| AISI / SAE (USA) | 1045 (G10450) |
| EN / DIN (Europe) | C45 (1.0503), C45E (1.1191), Ck45 |
| JIS (Japan) | S45C |
| BS 970 (UK) | 080M46 / EN9 |
| ISO | C45 |
45C8 and S45C are effectively the same grade under two naming systems; both carry roughly 0.45% carbon with a comparable manganese band. Against EN8D (the close-control EN8, around 0.40–0.45% C), 45C8 runs marginally higher carbon — see the 45C8 vs EN8D comparison for where each fits.
Can 45C8 be hardened? Heat treatment
Yes. 45C8 is most often supplied normalised, then through-hardened in small sections or surface-hardened (induction or flame) where a wear face is needed. Because it is a plain-carbon steel its hardenability is limited, so large sections do not harden uniformly to the core; size the part accordingly or move to an alloy grade. Temper immediately after quenching.
| Operation | Temperature |
|---|---|
| Forging | 1100–1250 |
| Normalising | 850–880 (air cool) |
| Annealing | 840–870 (furnace cool) |
| Hardening | 850–880 (water; oil for thin or intricate sections) |
| Tempering | 550–660 (to suit required hardness) |
Water-quenching complex shapes risks cracking — prefer oil or a milder medium for intricate parts.
What sizes and forms are available?
Ambhe Ferro rolls and finishes 45C8 across four product forms. Standard length is 5–6 m; custom cut lengths are made to order. Non-standard sizes are often available make-to-order against tonnage.
Rounds (hot rolled)
Bright bars
Hexagons
RCS
Supply conditions: hot rolled, annealed, normalised, or bright (cold drawn / polished). MOQ is 5 MT per size.
Applications of 45C8
45C8 is a workhorse for parts that carry moderate load and benefit from surface or through hardening. Common uses include:
- Transmission and machine shafts, axles and spindles
- Studs, bolts, pins, keys and couplings
- Gears, sprockets and levers for light-to-medium duty
- Crankshafts and connecting parts in general machinery
- Forged components — flanges, hubs, blanks
- Induction- or flame-hardened wear surfaces (rollers, guides, cams)
- Machined components for capital goods and auto parts
Why source 45C8 from Ambhe Ferro
- We roll it, we don't just stock it. Heat-to-heat consistency from our own rolling mill and bright-bar lines.
- ISO 9001 certified with an in-house QC laboratory testing every heat.
- Heat-wise mill test certificate on every dispatch; third-party inspection (SGS, BV, TÜV) on request.
- Multiple supply conditions — hot rolled, annealed, normalised, bright (cold drawn / polished).
- Over 39 years serving the Mumbai–Pune–Nashik corridor, with quick dispatch from our two factories in MIDC Murbad, near Kalyan — about 80 km from Mumbai Port and JNPT.
How to order 45C8 steel
Ambhe Ferro is an engineering-steel manufacturer with two factories in MIDC Murbad, near Kalyan — about 80 km from Mumbai Port and JNPT. We roll and finish 45C8 steel at our units and dispatch quickly across the Mumbai–Pune–Nashik corridor and pan-India. Regular dispatches go to buyers in Mumbai, Navi Mumbai, Thane, Vasai–Virar, Pune, Pimpri-Chinchwad, Chakan, Nashik, Ahmednagar, Aurangabad, Kolhapur, Nagpur, Rajkot, Ahmedabad and Bengaluru; exports are arranged on request. Order as hot-rolled rounds, bright bars, hexagons or RCS against your size and tonnage, with a heat-wise mill test certificate on every dispatch.
To raise an enquiry, send the grade, form, size and tonnage. We respond with pricing, availability and lead time. MOQ is 5 MT per size.
45C8 steel — frequently asked questions
What is 45C8 steel?
What is the chemical composition of 45C8?
What are the mechanical properties of 45C8?
What is 45C8 equivalent to?
Can 45C8 be hardened?
Is 45C8 weldable?
What is 45C8 used for?
What sizes and forms does Ambhe Ferro supply 45C8 in?
What is the MOQ for 45C8, and do you provide a mill test certificate?
45C8 vs EN8D — which should I choose?
Let's Talk 45C8
Tell us your grade, form, size, and tonnage. We'll respond with pricing, availability, and lead time — and a mill test certificate on every heat.