1008 Carbon Steel: Low-Carbon Mild Steel for Cold Forming & General Fabrication
1008 carbon steel (UNS G10080) is a low-carbon, cold-rolled mild steel grade widely utilized in applications requiring excellent formability, weldability, and moderate strength. With a maximum carbon content of 0.10%, this grade offers superior ductility for deep drawing, bending, and cold heading while maintaining sufficient hardness for structural components. This article explores its chemical composition, mechanical properties, processing characteristics, and industrial applications, providing technical insights for engineers and procurement professionals.
1. Chemical Composition (ASTM A1008/A1008M Standard)
| Element | Content Range | Function |
|---|---|---|
| Carbon (C) | ≤ 0.10% | Low carbon ensures high ductility and weldability; minimizes hardening during cold working |
| Manganese (Mn) | 0.30 – 0.50% | Enhances strength and hardenability; acts as a deoxidizer during steelmaking |
| Phosphorus (P) | ≤ 0.035% | Controlled impurity; excessive content reduces toughness and weldability |
| Sulfur (S) | ≤ 0.035% | Minimized to prevent hot shortness and improve machinability |
| Silicon (Si) | ≤ 0.10% | Residual element from deoxidation; slight increase improves strength |
| Copper (Cu) | ≤ 0.20% | Residual element; minor amounts improve atmospheric corrosion resistance |
2. Mechanical Properties (Cold-Rolled Condition)
- Tensile Strength (UTS): 305 – 440 MPa (varies by temper grade; DS Type B: 340 MPa min)
- Yield Strength (0.2% offset): 205 – 310 MPa (depends on cold reduction percentage)
- Elongation in 50mm: ≥ 38% (excellent for deep drawing and complex forming operations)
- Hardness (HRB): 45 – 60 (Rockwell B scale; softer for improved formability)
- Bend Test: 180° flat on itself (no cracking; demonstrates superior ductility)
- Shear Strength: ~240 MPa (suitable for stamping and blanking operations)
3. Manufacturing & Processing Characteristics
- Cold Rolling: Produced via continuous cold reduction mills with 30-60% reduction to achieve desired thickness (0.5mm – 3.0mm typical) and surface finish (matte, bright, or oiled).
- Annealing: Batch or continuous annealing at 650-720°C followed by controlled cooling to recystallize grain structure and restore ductility after cold working.
- Temper Rolling: Light cold reduction (0.5-2%) after annealing to minimize yield point elongation and improve flatness (common for DS Type B temper).
- Surface Treatment: Oiled (rust-preventative), dry (uncoated), or phosphated (for lubrication in forming) finishes available; pickling optional for scale removal.
- Forming: Ideal for deep drawing (LDR up to 2.1), bending (minimum bend radius = 0T for 90°), and cold heading (bolt/nut manufacturing).
4. Typical Industrial Applications
Automotive Components
Body panels, fuel tanks, brackets, and structural reinforcements where formability and weldability are critical; meets SAE J403 standards for chemical composition.
Appliance Manufacturing
Washing machine drums, refrigerator cabinets, and HVAC ductwork; selected for deep drawability and corrosion resistance when coated (e.g., galvanized or painted).
Fasteners & Hardware
Cold-headed bolts (Grade 2), nuts, and screws; low carbon content prevents cracking during heading operations and ensures consistent thread rolling.
Furniture & Enclosures
Office furniture frames, electrical enclosures, and metal cabinets; chosen for its balance of strength and formability in thin-gauge applications (18-24 ga typical).
Tubular Products
ERW (Electric Resistance Welded) tubes for furniture, automotive exhaust components, and mechanical applications; weldability enables seamless tube fabrication.
General Fabrication
Stamped parts, brackets, and structural shapes for industrial equipment; cost-effective alternative to higher-carbon steels when strength requirements are moderate.
5. Comparison with Similar Low-Carbon Grades
| Grade | Carbon Content | Key Properties | Primary Applications |
|---|---|---|---|
| 1008 | ≤ 0.10% | Highest ductility; excellent cold formability; lowest strength in class | Deep drawing, cold heading, complex stamping |
| 1010 | 0.08 – 0.13% | Slightly higher strength; balanced formability and machinability | General fabrication, shafts, lightly stressed components |
| 1012 | 0.10 – 0.15% | Improved strength with moderate ductility; better wear resistance | Gears, pins, moderately stressed structural parts |
| 1018 | 0.15 – 0.20% | Higher strength; reduced formability; better machinability | Machined parts, axles, high-stress components |
6. Selection Guidelines & Processing Recommendations
- Forming Considerations: For severe deep drawing, use DS (Drawing Steel) Type B temper; avoid over-lubrication to prevent surface defects. Anneal between operations if cold work hardening exceeds 40% reduction.
- Welding: Readily weldable by all conventional methods (MIG, TIG, resistance); preheat not required for thin sections (<6mm). Use E70S-6 filler wire for GMAW processes.
- Machining: Low carbon content results in gummy chips; use high-speed steel tools with positive rake angles and sharp edges. Sulphurized grades (e.g., 1008F) improve machinability.
- Corrosion Protection: Not corrosion-resistant in bare condition; apply zinc coating (galvanizing), phosphate treatment, or paint for outdoor/exposed applications.
- Heat Treatment: Not hardenable by heat treatment; stress relief annealing at 595-650°C recommended after severe cold working to prevent distortion.
- Quality Standards: Verify compliance with ASTM A1008 (cold-rolled) or A1011 (hot-rolled) standards; request mill test reports (MTR) for critical applications.
7. Request a Carbon Steel Quote
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