AISI 1045 Round Bars – 1045 Carbon Steel Round Bar (C45 / S45C)
ASC LLP, Mumbai, supplies AISI 1045 round bars in hot-rolled, bright (cold-drawn), turned and polished, and forged condition, from 10 mm to 500 mm diameter. In addition, every lot comes with a mill test certificate. See also our full range of carbon steel bars.
What is AISI 1045 Steel?
AISI / SAE 1045 (UNS G10450) is a medium-carbon steel with about 0.45% carbon. As a result, it is stronger and harder than low-carbon grades such as 1018 or 1020, yet it still machines well and responds to hardening and tempering.
Importantly, 1045 is normally sold to chemical composition, so its strength depends on the supply condition: hot rolled, cold drawn, normalised, or quenched and tempered. For this reason, the condition should always be stated on the order.
1045 Round Bar – Quick Facts
- Grade: AISI / SAE 1045, UNS G10450
- Carbon: 0.43–0.50%, with 0.60–0.90% manganese
- Standards: ASTM A29 for hot-wrought bars, while A108 covers cold-finished bars
- Equivalents: C45 (1.0503), C45E / Ck45 (1.1191), JIS S45C and IS 1570 C45
- Sizes: 10 mm to 500 mm diameter; in addition, hex, square and flat bars
- Surface hardening: suitable for induction and flame hardening
Key Properties of 1045 Steel Bars
- Medium strength: higher tensile and yield strength than 1018 or 1020, so it suits shafts and pins.
- Heat treatable: it can be hardened and tempered; moreover, the surface can be induction hardened for wear.
- Good machinability: especially in the normalised or annealed condition.
- Limited weldability: the 0.45% carbon means preheat and post-heat are needed to avoid cracking.
- Limited hardenability: as a plain carbon steel, it hardens through only in smaller sections; therefore, 4140 is used for large, highly stressed parts.
Forms of 1045 Steel Bar We Supply
- Hot-rolled (black) round bar: mill finish, for forging and general machining.
- Bright bar (cold drawn): smooth surface and close tolerance; in addition, higher strength from cold work.
- Turned and polished / peeled bar: decarburised skin removed, so it suits precision shafts.
- Forged round bar: similarly, for large diameters and heavy-duty parts.
- Hex, square and flat bars: for fasteners, keys and machined components.
1045 Round Bar Heat Treatment
| Process | Temperature | Notes |
| Full annealing | 800 – 850 °C | Slow furnace cool, which gives the softest condition |
| Normalising | 840 – 880 °C | Air cool to refine the grain |
| Hardening | 820 – 860 °C | Quench in water or oil, depending on section |
| Tempering | 550 – 660 °C | Sets the final strength and toughness |
| Induction / flame hardening | Surface only | Hard, wear-resistant case, while the core stays tough |
AISI 1045 Round Bar Specifications
| Item | Details |
| Grade | AISI / SAE 1045, UNS G10450 |
| Standards | ASTM A29 (hot-wrought); in addition, ASTM A108 (cold-finished) |
| Diameter | 10 mm to 500 mm; larger sizes as forgings |
| Length | Mill lengths of 3 – 6 m, or alternatively cut to length |
| Condition | As rolled, normalised, annealed, cold drawn, or quenched and tempered |
| Testing | Chemistry and hardness; moreover, tensile, UT and impact on request |
| Certificate | EN 10204 3.1; also 3.2 on request |
AISI 1045 Chemical Composition
| Element | 1045 (%) |
| Carbon (C) | 0.43 – 0.50 |
| Manganese (Mn) | 0.60 – 0.90 |
| Silicon (Si) | 0.10 – 0.35 (typical) |
| Phosphorus (P) | 0.040 max |
| Sulphur (S) | 0.050 max |
| Iron (Fe) | Balance |
ASTM A29 sets the carbon, manganese, phosphorus and sulphur limits. By contrast, silicon is not specified unless ordered, although most killed-steel bars contain about 0.10–0.35%.
1045 Round Bar Mechanical Properties by Condition
| Condition | Tensile (MPa) | Yield (MPa) | Elongation (%) | Hardness (HB) |
| Hot rolled | about 565 – 600 | about 300 – 310 | 14 – 16 | about 163 – 179 |
| Cold drawn (bright) | about 625 – 690 | about 500 – 540 | 8 – 12 | about 190 – 207 |
| Quenched & tempered, up to 40 mm | 650 – 800 | 430 min | 16 min | – |
| Quenched & tempered, 100 – 250 mm | 590 – 740 | 340 min | 18 min | – |
These are typical values only; actual results are shown on the mill certificate. Note that strength falls as diameter increases, because thick sections cool more slowly when quenched.
Applications of AISI 1045 Round Bars
| Industry | Typical 1045 round bar use |
| Automotive | Axles, shafts and crankshafts, as well as pins and studs |
| Machinery | Spindles, gears, couplings and rollers |
| Hydraulics | Piston rods, usually induction hardened and chrome plated |
| Agricultural equipment | Shafts and wear parts, while loads are moderate |
| Forging | Forged flanges, hubs and machine parts |
1045 Steel Equivalent Grades – C45, Ck45, S45C
| Standard | Equivalent grade |
| EN 10083-2 | C45 (1.0503); C45E / Ck45 (1.1191) with tighter P and S |
| JIS G4051 | S45C |
| IS 1570 (Part 2) | C45 (formerly 45C8) |
| BS 970 | 080M46, whereas EN8 (080M40) is close but slightly lower in carbon |
1045 vs 1018 / 1020 vs 4140
AISI 1018 and 1020 are low-carbon steels, so they weld easily but cannot be hardened much. In contrast, 4140 adds chromium and molybdenum, which gives deeper hardening and guaranteed tensile properties. Therefore, 1045 sits in the middle: stronger than 1018, yet cheaper than 4140.
Why Buy 1045 Round Bars from ASC LLP?
- Traceable material: mill certificates with chemistry, condition and hardness.
- Correct condition advice: help choosing hot rolled, bright or hardened and tempered bars, because the application decides the condition.
- Cut to length: bars sawn to size, so less machining is needed.
- Export packing: finally, bundles are tagged and packed for sea shipment.
Welding 1045 Steel Bars
1045 can be welded by MIG, TIG and MMA. However, its carbon content makes the heat-affected zone hard, so preheat (typically 150–260 °C, depending on section) and slow cooling or post-heat are needed. For welded fabrications, a low-carbon grade such as S275JR is often a better choice.
For hollow 1045 sections, see our ASTM A519 1045 tubes, as well as the full range of carbon steel products.
Frequently Asked Questions – AISI 1045 Round Bars
What is AISI 1045 round bar?
In short, it is a medium-carbon steel bar with about 0.45% carbon, used for shafts, axles, gears and other machined parts that need more strength than mild steel.
What is the chemical composition of 1045 steel?
It contains C 0.43–0.50%, Mn 0.60–0.90%, P 0.040% max and S 0.050% max, with silicon typically 0.10–0.35%.
What is the tensile strength of 1045 round bar?
It depends on condition. Hot-rolled bar is typically about 565–600 MPa, while cold-drawn bar reaches about 625–690 MPa, and hardened and tempered bar up to about 800 MPa.
What is the equivalent of AISI 1045?
The main equivalents are C45 (1.0503), C45E / Ck45 (1.1191), JIS S45C and IS C45. EN8 is similar but has slightly less carbon.
Can 1045 steel be hardened?
Yes. It can be quenched and tempered, and the surface can also be induction or flame hardened, while the core stays tough.
Is 1045 steel weldable?
It is weldable with care. Preheat and controlled cooling are needed, because its carbon content can cause cracking.
What is the difference between 1045 and 4140?
1045 is a plain carbon steel. 4140, on the other hand, contains chromium and molybdenum, so it hardens more deeply and is stronger in large sections.
Global Supply
ASC LLP supplies AISI 1045 round bars from Mumbai to customers in India, the Middle East, Europe, Africa, the Americas and South-East Asia. To get a prompt quotation, simply send your enquiry with diameter, length, condition and quantity.
Countries We Export To
UNITED STATES, EUROPE, UK, UAE, SAUDI ARABIA, OMAN, KUWAIT, JORDAN, QATAR, INDONESIA, MALAYSIA, BRAZIL, SPAIN, ITALY, FRANCE, GERMANY, BAHRAIN, SRI LANKA, AZERBAIJAN, AUSTRALIA, AUSTRIA, PHILIPPINES, TURKEY, RUSSIA, IRAN, IRAQ, CANADA, KOREA, JAPAN, YEMEN, FINLAND, ZIMBABWE, HUNGARY, PORTUGAL, VIETNAM, MOROCCO, THAILAND, SOUTH AFRICA, MEXICO, SINGAPORE, GREECE, KUWAIT, POLAND, NEW ZEALAND, SWEDEN, SWITZERLAND, BELGIUM, BHUTAN, BANGLADESH, TAIWAN, ROMANIA, CAMBODIA, KAZAKHSTAN, AFGHANISTAN.
