SteelWhat is 1045 steel and what is it used for? Medium-carbon steel
1045 steel is the most common medium-carbon steel: when you need more strength and hardness than a low-carbon steel, it is the benchmark. In this guide we explain what 1045 steel is, its composition, its properties, what it is used for and the sizes we stock.
What is 1045 steel?
Medium-carbon steel (SAE/AISI 1045) with a good combination of mechanical strength, hardness, toughness, and machinability; compared with low-carbon steels, it withstands higher loads, moderate impact, and wear conditions. It can be supplied hot forged, hot rolled, cold drawn, normalized, annealed, or heat treated. It accepts quenching and tempering, as well as induction or flame surface hardening. It is used in shafts, gears, bolts, keys, rollers, screws, and machined components subject to mechanical stress; because of its medium carbon content, it has limited weldability.
Chemical composition of 1045 steel
This is the typical composition of 1045 steel (AISI 1045 / EN C45 / DIN Ck45 / JIS S45C standard):
| Element | Contents | What for? |
|---|---|---|
| Carbon (C) | 0.43 – 0.50 % | Provides hardness and strength |
| Silicon (Si) | 0.15 – 0.35 % | Deoxidizer, adds strength |
| Manganese (Mn) | 0.60 – 0.90 % | Hardenability and strength |
| Phosphorus (P) | 0.040 % max. | Impurity, kept low |
| Sulfur (S) | 0.050 % max. | Impurity, kept low |
Hardness and heat treatment of 1045 steel
1045 is a medium-carbon steel, so unlike 1018 it does accepts quenching and tempering: with heat treatment it reaches high hardness (on the order of 45 to 55 HRC depending on the tempering) and it can also be surface-hardened by induction or flame. Rolled or drawn, it is around 170 to 200 HB. In exchange for that greater strength, its weldability is limited by carbon content. We explain the hardness scales in steel hardness.
What is it for? Applications of 1045
1045 steel is mainly used in:
- Axles and shafts
- Gears and pinions
- High-strength bolts
- Studs and bolts
- Industrial rollers
- Crankshafts and connecting rods
- Mechanical couplings
- Wedges and keys
- Machinery components
Forms and sizes we carry
At NAT MAC we stock 1045 steel in these forms and sizes:
| Package size | Sizes |
|---|---|
| Plates | 1/2" – 10" (12.7 – 254 mm) |
| Round bars | 1/4" – 4" (6.3 – 101.6 mm) |
| Flat bars | Made to length |
If you need a particular size, tell us which one and we will gladly source it for you.
1045 equivalents and standards
1045 steel is also identified by these standards: AISI 1045 / EN C45 / DIN Ck45 / JIS S45C You can see how to read them in our article on steel standards.
In summary
- 1045 is a medium-carbon steel with good strength, hardness and toughness
- Typical composition: C 0.43–0.50 %, Mn 0.60–0.90 %
- Accepts quenching and tempering (45–55 HRC) and induction hardening; limited weldability
- Ideal for shafts, gears, crankshafts, bolts and machinery components
- We carry it in plates, round bars, flat bars, cut to size
Why buy 1045 steel at NAT MAC?
We have more than 54 years of experience as an industrial supplier and ISO 9001 certified quality. We carry a wide range of carbon steels and help you choose the right one for your part.
- Quality 1045 Steel, backed and traceable
- Material cut to the size you need
- Technical advice on choosing the right grade
- Wide range of carbon steels in stock
- On-time deliveries and competitive prices
Tell us what you are going to make and in what dimensions, and we will recommend the right material and form. Request your free quote.
Sources: data sheet from our NAT MAC catalog (composition, sizes and applications) and public industry references for hardness. Values are for reference and may vary by standard, heat and treatment.
