AISI 1035 Carbon Steel: Medium-Carbon Structural Steel for Machining & Industrial Applications
AISI 1035 carbon steel is a medium-carbon, medium-tensile grade widely used in industrial applications requiring balanced strength, machinability, and wear resistance. With a nominal carbon content of 0.35%, this non-alloy steel offers excellent cold-forming properties while maintaining good weldability under controlled conditions. This article explores its chemical composition, mechanical properties, heat treatment processes, and typical applications in machinery, automotive, and construction sectors.
1. Chemical Composition (ASTM A29/A29M Standard)
| Element | Content Range | Function |
|---|---|---|
| Carbon (C) | 0.32 – 0.38% | Primary hardening element; determines strength and hardenability |
| Manganese (Mn) | 0.60 – 0.90% | Enhances strength and hardenability; deoxidizes during steelmaking |
| Phosphorus (P) | ≤ 0.040% | Impurity; controlled to prevent embrittlement |
| Sulfur (S) | ≤ 0.050% | Impurity; limited to improve machinability and ductility |
| Silicon (Si) | 0.15 – 0.35% | Deoxidizer; improves strength without sacrificing ductility |
| Copper (Cu) | ≤ 0.20% | Residual element; excessive amounts may affect surface quality |
2. Mechanical Properties (As-Rolled Condition)
- Tensile Strength (σb): 550 – 700 MPa (varies with heat treatment)
- Yield Strength (σ0.2): 310 – 400 MPa (minimum 310 MPa per ASTM standards)
- Elongation (δ): ≥ 20% in 50mm (good ductility for forming operations)
- Hardness (HB): 143 – 179 (Brinell hardness in normalized condition)
- Impact Toughness (CVN): ≥ 27 J at 20°C (varies with temperature and treatment)
- Machinability Rating: 65% (relative to AISI 1212 as 100% baseline)
3. Heat Treatment Processes
- Normalizing: Heat to 870-920°C, air cool. Produces uniform grain structure, improves machinability, and relieves internal stresses. Typical hardness: 143-179 HB.
- Annealing: Heat to 840-870°C, furnace cool. Softens material for cold working (hardness: ≤ 170 HB). Spheroidize annealing at 700-720°C enhances machinability for complex parts.
- Quenching & Tempering: Austenitize at 840-870°C, water/oil quench, then temper at 540-680°C. Achieves tensile strength of 600-800 MPa with improved toughness.
- Case Hardening: Carbonitriding or carburizing at 850-900°C followed by quenching. Produces surface hardness of 55-62 HRC for wear-resistant components.
- Stress Relieving: Heat to 500-650°C, air cool. Recommended after welding or machining to reduce residual stresses.
4. Typical Applications by Industry
Machinery & Equipment
Gears, shafts, axles, spindles, and couplings where moderate strength and wear resistance are required. Common in agricultural machinery, conveyors, and power transmission systems.
Automotive Components
Steering knuckles, wheel hubs, crankshafts (for small engines), and suspension parts. Often used in normalized or quenched-and-tempered conditions for balanced properties.
Construction & Infrastructure
Structural bolts, anchor rods, and reinforcing bars for concrete. Suitable for welded structures when proper preheat (150-200°C) and post-weld heat treatment are applied.
General Engineering
Forged components, hydraulic cylinders, and tool holders. Case-hardened 1035 steel is used for wear-resistant parts like cam followers and light-duty dies.
5. Comparison with Similar Carbon Steel Grades
| Grade | Carbon Content | Key Properties | Typical Applications |
|---|---|---|---|
| AISI 1035 | 0.32-0.38% | Balanced strength and ductility; good machinability | Shafts, gears, automotive parts, structural components |
| AISI 1045 | 0.43-0.50% | Higher strength but lower ductility; better wear resistance | Heavy-duty shafts, axles, and high-stress machine parts |
| AISI 1020 | 0.18-0.23% | Lower strength but excellent weldability and formability | Sheet metal parts, welded structures, low-stress applications |
| AISI 1050 | 0.48-0.55% | High strength and hardness; limited weldability | Spring clips, hand tools, and high-wear components |
6. Fabrication & Processing Guidelines
- Machining: Best performed in normalized or annealed condition. Use high-speed steel or carbide tools with coolant. Typical speeds: 60-80 m/min for turning, 30-50 m/min for drilling.
- Welding: Preheat to 150-200°C for sections > 25mm. Use E7018 or ER70S-6 filler materials. Post-weld stress relief recommended for critical applications.
- Forging: Hot forge at 1050-1250°C. Avoid working below 850°C to prevent cracking. Cool slowly in furnace or insulated medium after forging.
- Cold Working: Suitable for bending, swaging, and heading in annealed condition. Severe cold working may require intermediate annealing.
- Surface Treatment: Responds well to phosphating, black oxidizing, and electroplating (zinc, nickel). Shot peening improves fatigue resistance.
7. Request a Carbon Steel Quote
Need AISI 1035 carbon steel in custom sizes or specifications? Contact Baoli Iron & Steel for competitive pricing on bars, plates, forgings, and machined components. Our metallurgists provide technical support for heat treatment and application optimization.