AISI 1045 Carbon Steel Round Bar
AISI 1045 is a versatile medium-carbon steel round bar with higher strength and hardness than low-carbon grades. Diameter from 6mm to 500mm, available in hot rolled, cold drawn, and Q&T conditions for shafts, gears, bolts, and heavy-duty machinery components.
| Material | Carbon Steel (Medium Carbon) |
|---|---|
| Grade / Standard | AISI 1045 / SAE 1045 |
| Diameter | 6mm - 500mm |
| Length | 3m / 6m / 12m (or cut to length) |
| Delivery Condition | hot_rolled / normalized / quenched_tempered / annealed / as_rolled |
| Surface Treatment | bare / polished / coated |
| MOQ | 1 Ton |
| Delivery Time | 10-25 Days / In Stock |
| Loading Port | Tianjin / Shanghai / Qingdao |
Overview of AISI 1045 Carbon Steel Round Bar
AISI 1045 is a widely used medium-carbon steel round bar specified under AISI/SAE 1045 standard with carbon content typically 0.43-0.50%. This grade provides significantly higher strength and hardness than low-carbon grades like AISI 1020, while retaining reasonable machinability and moderate weldability. AISI 1045 round bar is the preferred choice for components requiring higher tensile strength, good wear resistance, and the ability to be through-hardened via quenching and tempering.
With a tensile strength of approximately 570-700 MPa in the as-rolled condition and the ability to be through-hardened to HRC 55-60, 1045 steel round bar delivers excellent performance for heavily loaded shafts, gears, bolts, and structural pins. It is widely stocked by steel service centers worldwide due to its proven mechanical properties and versatile heat treatment response, making it one of the most commonly specified medium-carbon steel grades in global engineering.
Key Features and Manufacturing Methods
AISI 1045 carbon steel round bar is manufactured through three primary processes: hot rolled (HR), cold drawn (CD), and turned/peeled/forged. Hot rolled bars provide the most economical option with mill scale surface, suitable for general fabrication and applications where subsequent machining is planned. Cold drawn bars offer improved dimensional accuracy (h11/h13 tolerance), superior surface finish (Ra 1.6-3.2μm), and enhanced mechanical properties through cold working strain hardening.
The round bar is supplied in diameter range from 6mm to 500mm, with standard lengths of 3 meters, 6 meters, and 12 meters. Custom cutting service is available for specific length requirements. Surface conditions include black (mill finish), bright (cold drawn), peeled, and ground depending on application needs. The grade can be supplied as-rolled, normalized, annealed, or quenched and tempered (Q+T), and responds exceptionally well to both through-hardening and induction surface hardening heat treatment processes.
Main Applications of AISI 1045 Round Bar
AISI 1045 carbon steel round bar is extensively used for high-load machinery component manufacturing including drive shafts, motor shafts, pump shafts, transmission shafts, spindle shafts, and hydraulic cylinder rods. The grade’s excellent heat treatment response makes it ideal for gears, sprockets, couplings, bolts, studs, and pins requiring high strength and wear resistance. Its good machinability in the normalized or annealed condition supports efficient CNC turning, milling, and drilling operations.
The automotive industry uses 1045 round bar for crankshafts, connecting rods, steering components, axle shafts, and transmission gears. In the construction and mining sectors, it serves as raw material for hydraulic press cylinders, heavy-duty pins, roller shafts, drill rods, and crushing equipment components. Other applications include forging blanks for flanges and fittings, wood working tool bodies, wrenches and hand tools, agricultural equipment shafts, and general mechanical engineering components requiring through-hardened or induction-hardened wear surfaces.
Why Choose Us for AISI 1045 Carbon Steel Round Bar
Shandong Tanglu Metal Material Co., Ltd. supplies premium AISI 1045 carbon steel round bar sourced from major Chinese special steel mills with strict process control and reliable quality assurance. We offer flexible diameter ranges from small 6mm bars for precision components to large 500mm forged bars for heavy machinery applications, with multiple delivery conditions including hot rolled, cold drawn, peeled, normalized, annealed, and quenched & tempered options.
With monthly supply capacity of 8,000 tons of carbon steel bars and established export experience to over 50 countries, we support both small trial orders for product evaluation and large bulk orders for ongoing manufacturing supply. Each shipment includes original mill test certificate (MTC) conforming to EN 10204 3.1 standard, with EN 10204 3.2 and third-party inspection (SGS, BV, ABS, DNV, LR) available upon request for critical project applications.
📐 Dimension & Size Table
| Diameter (mm) | Length (m) | Weight (kg/m) | Tolerance |
|---|---|---|---|
| 6 | 3 / 6 | 0.222 | ± 0.30mm |
| 8 | 3 / 6 | 0.395 | ± 0.30mm |
| 10 | 6 / 12 | 0.617 | ± 0.30mm |
| 12 | 6 / 12 | 0.888 | ± 0.40mm |
| 16 | 6 / 12 | 1.578 | ± 0.40mm |
| 20 | 6 / 12 | 2.466 | ± 0.40mm |
| 25 | 6 / 12 | 3.853 | ± 0.50mm |
| 30 | 6 / 12 | 5.549 | ± 0.50mm |
| 40 | 6 / 12 | 9.864 | ± 0.60mm |
| 50 | 6 / 12 | 15.413 | ± 0.80mm |
| 60 | 6 / 12 | 22.195 | ± 0.80mm |
| 80 | 6 / 12 | 39.458 | ± 1.10mm |
| 100 | 6 / 12 | 61.654 | ± 1.30mm |
| 150 | 3 / 6 | 138.722 | ± 1.80mm |
| 200 | 3 / 6 | 246.617 | ± 2.50mm |
| 250 | 3 / 6 | 385.339 | ± 3.50mm |
| 300 | 3 / 6 | 554.888 | ± 4.50mm |
| 400 | 3 / 6 | 986.467 | ± 6.00mm |
| 500 | 3 / 6 | 1541.354 | ± 8.00mm |
* Custom sizes available upon request. Tolerances per relevant international standards.
🔬 Chemical Composition
| Element | Min | Max | Display Value | Note |
|---|---|---|---|---|
| C | 0.43 | 0.50 | 0.43-0.50 | Medium carbon range |
| Mn | 0.50 | 0.80 | 0.50-0.80 | |
| P | - | 0.040 | ≤0.040 | |
| S | - | 0.050 | ≤0.050 | |
| Si | 0.17 | 0.37 | 0.17-0.37 | |
| Cr | - | 0.25 | ≤0.25 | Residual element |
| Ni | - | 0.25 | ≤0.25 | Residual element |
| Cu | - | 0.25 | ≤0.25 | Residual element |
* Chemical composition may vary by heat, thickness and specification. Please refer to the actual mill test certificate.
⚙️ Mechanical Properties
| Property | Value | Unit | Test Condition |
|---|---|---|---|
| Tensile Strength (Hot Rolled) | 570-700 | MPa | As-rolled condition |
| Yield Strength (Hot Rolled) | ≥310 | MPa | Diameter ≤25mm |
| Elongation | ≥16 | % | Gauge length 50mm, hot rolled |
| Reduction of Area | ≥40 | % | Hot rolled condition |
| Brinell Hardness (Hot Rolled) | 170-210 | HBW | As-rolled condition |
| Impact Energy | ≥20 | J | Charpy V-notch at 20°C |
| Tensile Strength (Q&T) | 700-1000 | MPa | Quenched & tempered |
| Hardness (Q&T) | 22-32 | HRC | Depending on tempering temp |
| Surface Hardness (Induction) | 55-60 | HRC | After induction hardening |
| Tensile Strength (Cold Drawn) | 630-780 | MPa | Cold drawn condition |
| Yield Strength (Cold Drawn) | ≥490 | MPa | Cold drawn condition |
* Values shown are minimum requirements unless otherwise stated.
📦 Commercial Information
| Packaging | Standard seaworthy export packing. Round bars bundled in hexagonal bundles with 3-5 steel strapping bands per bundle, weight typically 2-5 tons per bundle. Plastic end caps for bars over 50mm diameter. Each bundle clearly tagged with heat number, grade, diameter, and length. Custom packaging including wooden crates available for premium polished bars or international air shipment. |
|---|---|
| Payment Terms | T/T (Telegraphic Transfer),L/C (Letter of Credit),D/P (Documents against Payment),Western Union,PayPal |
| Price Term | FOB,CFR,CIF,EXW |
| Supply Capacity | 8,000 Tons/Month (Carbon Steel Bars) |
| Loading Port | Tianjin / Shanghai / Qingdao |
Why Choose Our AISI 1045 Carbon Steel Round Bar?
Higher Strength & Through-Hardening Capability
Medium carbon content (0.43-0.50%) enables tensile strength up to 1000 MPa in Q&T condition and surface hardness up to HRC 60 with induction hardening, providing superior load-bearing capacity and wear resistance compared to low-carbon grades.
Comprehensive Diameter Range
Diameter range from 6mm precision bars to 500mm heavy industrial bars, available in standard 3m / 6m / 12m lengths. Custom cutting and length requirements supported with precision tolerance per ISO 286 h11/h13.
Multiple Surface Finish Options
Available in hot rolled (black), cold drawn (bright), peeled, and ground surface finishes. Cold drawn bars achieve surface roughness Ra 1.6-3.2μm, suitable for direct CNC machining without additional surface preparation.
Excellent Heat Treatment Response
Responds exceptionally well to normalizing, annealing, quenching & tempering, and induction hardening. Enables precise control of mechanical properties from soft machinable state to high-strength hardened condition per application requirements.
Mill Certified Quality & Reliable Supply
Original MTC with EN 10204 3.1/3.2 certification. Common diameters maintained in stock for 7-15 days dispatch. Third-party inspection available. 8,000 tons monthly capacity ensures consistent project supply.
🏭 Applications of AISI 1045 Carbon Steel Round Bar
AISI 1045 carbon steel round bar is the standard choice for high-strength shaft applications including drive shafts, motor shafts, pump shafts, transmission shafts, spindle shafts, and hydraulic cylinder rods. Its excellent through-hardening capability makes it ideal for gears, sprockets, couplings, high-strength bolts, studs, and structural pins requiring superior load-bearing capacity. The automotive industry relies on 1045 for crankshafts, axle shafts, steering components, and transmission gears. In construction and mining, it serves as raw material for heavy-duty pins, roller shafts, drill rods, and crushing equipment components. After induction hardening, 1045 round bar provides exceptional surface wear resistance for conveyor shafts, press cylinders, forging dies, and wood working tool bodies.
📋 Quality & Certification
Our Certifications
- ✅ ISO 9001:2015
- ✅ CE Marking
- ✅ ABS
- ✅ DNV GL
- ✅ Lloyd's Register (LR)
- ✅ Bureau Veritas (BV)
- ✅ SGS Certified
- ✅ NK
- ✅ RINA
Mill Certificate Type
- 📋 EN 10204 3.1
- 📋 EN 10204 3.2
- 📋 Original Mill Certificate
- 📋 Third Party Inspection Available
- 📋 Certificate of Origin
❓ Frequently Asked Questions
What is AISI 1045 carbon steel round bar?
AISI 1045 is a medium-carbon steel round bar specified under AISI/SAE 1045 standard with carbon content of 0.43-0.50%. It is one of the most widely used medium-carbon steel grades for engineering applications requiring higher strength and hardness than low-carbon grades. The bar is suitable for high-load shafts, gears, bolts, pins, and through-hardened or induction-hardened wear components with excellent mechanical property response to heat treatment.
What is the equivalent grade of AISI 1045?
AISI 1045 has equivalent grades in multiple international standards: SAE 1045 (US Society of Automotive Engineers), ASTM A108 1045 (US specification), EN C45 / 1.0503 (European standard EN 10083), DIN C45 (German standard), JIS S45C (Japanese standard JIS G4051), and GB 45# or GB 45 (Chinese standard GB/T 699). While these grades share similar mechanical properties and chemical composition, exact substitution should be verified against specific project requirements, especially for heat-treated applications.
What is the difference between AISI 1020 and AISI 1045?
The primary difference is carbon content: AISI 1020 has 0.17-0.23% C while AISI 1045 has 0.43-0.50% C. This gives AISI 1045 significantly higher tensile strength (570-700 MPa vs 380-470 MPa), higher hardness (170-210 HBW vs 111-156 HBW), and the ability to be through-hardened via quenching. However, AISI 1045 has lower ductility (16% elongation vs 25%), reduced weldability (requires preheating), and higher cost. AISI 1020 is preferred for weldability and cold-forming; AISI 1045 is preferred for strength and heat treatment.
Can AISI 1045 round bar be welded?
AISI 1045 can be welded, but requires more care than low-carbon grades due to its higher carbon content. Preheating to 200-300°C is recommended before welding, and low-hydrogen welding electrodes (E7018 or equivalent) should be used. Post-weld heat treatment (stress relieving at 550-650°C) is advisable for critical applications to prevent hydrogen cracking and reduce residual stresses. For welded structural applications where no heat treatment is planned, AISI 1020 is generally a better choice.
What heat treatments are available for AISI 1045?
AISI 1045 responds well to multiple heat treatment processes: 1) Normalizing (840-880°C, air cool) — refines grain structure, improves uniformity. 2) Annealing (800-840°C, furnace cool) — softens for maximum machinability (HBW 150-180). 3) Quenching & Tempering (quench 820-850°C in water or oil, temper 400-650°C) — achieves tensile 700-1000 MPa with controlled toughness. 4) Induction hardening — surface hardness HRC 55-60 with tough core, ideal for shaft journals and gear teeth. 5) Stress relieving (550-650°C) — reduces residual stresses after machining or welding.
What sizes and lengths are available for AISI 1045 round bar?
AISI 1045 round bar is available in diameter range from 6mm to 500mm. Standard lengths include 3 meters, 6 meters, and 12 meters, with custom cut-to-length service supported for specific project requirements. Diameter tolerance per ISO 286 h11 (for cold drawn) or DIN 1013 (for hot rolled). For diameters over 200mm, lengths are typically 3-6 meters due to forging or rolling process limitations. Special long lengths up to 18 meters available for selected sizes upon request.
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AISI 1045 Carbon Steel Round Bar
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