Table of Contents
Introduction
FC-0208 is one of the most widely used iron-copper powder metallurgy materials, offering an excellent balance of strength, machinability, and cost-effectiveness for medium-duty structural components. The designation indicates:
- F = Ferrous (iron-based)
- C = Copper alloying element
- 02 = 2% copper content (nominal)
- 08 = 0.8% combined carbon (graphite added + infiltrated carbon)
This material delivers tensile strengths of 380-520 MPa depending on density and heat treatment, making it ideal for automotive gears, small engine components, power tool parts, and structural brackets where cost-effective strength is required.
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Material Composition & Specification
Standard Composition (MPIF Standard 35)
| Element | Nominal Content | Typical Range | Purpose |
|---|---|---|---|
| Iron (Fe) | Balance | 97.2-97.8% | Base material, structural strength |
| Copper (Cu) | 2.0% | 1.8-2.2% | Strengthening, machinability, corrosion resistance |
| Graphite (C) | 0.8% | 0.6-0.9% | Hardenability, wear resistance |
| Other Elements | <0.5% | — | Lubricants, trace impurities |
Copper Addition Benefits:
- ✅ Increases tensile strength 25-35% vs. straight iron
- ✅ Improves sinterability (liquid phase sintering at Cu melting point)
- ✅ Enhances machinability (copper acts as lubricant during cutting)
- ✅ Provides modest corrosion resistance (copper protective layer)
Carbon Addition Benefits:
- ✅ Enables heat treatment response (carburizing, case hardening)
- ✅ Improves wear resistance (forms iron carbides)
- ✅ Increases hardness after heat treatment
Mechanical Properties by Density
As-Sintered Properties (No Heat Treatment)
| Density Grade | g/cm³ | % Theoretical | Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|---|---|---|
| Low Density | 6.6-6.8 | 84-87% | 310-380 MPa | 220-280 MPa | <1% | 50-65 HRB |
| Medium Density | 6.9-7.1 | 88-90% | 380-450 MPa | 280-340 MPa | 1-2% | 60-75 HRB |
| High Density | 7.2-7.4 | 92-94% | 450-520 MPa | 340-400 MPa | 2-3% | 70-85 HRB |
Density Selection Criteria:
- Low density (6.6-6.8 g/cm³): Cost-optimized for static loads, bushings, low-stress brackets
- Medium density (6.9-7.1 g/cm³): Standard for most applications, good strength/cost balance
- High density (7.2-7.4 g/cm³): Higher strength, better fatigue resistance, wear applications
Heat-Treated Properties (Quench + Temper)
Typical Heat Treatment: Oil quench from 870°C + temper at 200°C
| Density Grade | Tensile Strength | Yield Strength | Hardness | Impact Strength |
|---|---|---|---|---|
| 6.6-6.8 g/cm³ | 480-580 MPa | 420-520 MPa | 25-35 HRC | 8-12 J (Charpy) |
| 6.9-7.1 g/cm³ | 580-680 MPa | 520-620 MPa | 30-40 HRC | 12-18 J |
| 7.2-7.4 g/cm³ | 680-780 MPa | 620-720 MPa | 35-45 HRC | 18-24 J |
Heat Treatment Benefits:
- ✅ 50-70% increase in tensile strength
- ✅ Significant hardness increase (HRB → HRC range)
- ✅ Improved wear resistance
- ✅ Enhanced fatigue life (40-60% improvement)
Limitations:
- ⚠️ Ductility decreases (elongation drops to <1%)
- ⚠️ Adds $0.30-$0.80 per part processing cost
- ⚠️ May cause distortion (requires sizing/grinding)
Fatigue & Dynamic Properties
Fatigue Strength (Rotating Bending)
| Density | As-Sintered Fatigue Limit | Heat-Treated Fatigue Limit | Test Cycles |
|---|---|---|---|
| 6.8 g/cm³ | 140-170 MPa | 220-260 MPa | 10⁷ cycles |
| 7.1 g/cm³ | 170-210 MPa | 260-310 MPa | 10⁷ cycles |
| 7.4 g/cm³ | 210-250 MPa | 310-370 MPa | 10⁷ cycles |
Fatigue Performance Factors:
- Higher density = longer fatigue life (reduced stress concentration at pores)
- Surface densification improves fatigue strength 30-50%
- Shot peening adds 20-40% fatigue life improvement
Wear Resistance
Sliding Wear Performance (Pin-on-Disk Test):
| Material Condition | Wear Rate (mm³/Nm) | Coefficient of Friction | Applications |
|---|---|---|---|
| As-Sintered | 2.5 - 4.0 × 10⁻⁶ | 0.35 - 0.45 | Bushings with lubrication |
| Heat-Treated | 1.2 - 2.0 × 10⁻⁶ | 0.25 - 0.35 | Gears, sliding contacts |
| Case Hardened | 0.5 - 1.0 × 10⁻⁶ | 0.20 - 0.30 | High-wear applications |
Wear Improvement Methods:
- Steam treatment (creates Fe₃O₄ surface layer, fills surface porosity)
- Case carburizing + hardening (increases surface hardness to 58-62 HRC)
- Resin/oil impregnation (fills porosity, reduces friction)
Physical & Thermal Properties
Physical Characteristics
| Property | Value | Units | Notes |
|---|---|---|---|
| Density Range | 6.6 - 7.4 | g/cm³ | Varies with compaction pressure |
| Theoretical Density | 7.85 | g/cm³ | 100% dense wrought steel |
| Typical Porosity | 6-16% | vol% | Controlled interconnected pores |
| Permeability | 0-50 | millidarcies | Oil retention capability |
| Electrical Resistivity | 18-25 | µΩ·cm | Higher than wrought (porosity effect) |
| Magnetic Properties | Ferromagnetic | — | Suitable for magnetic applications |
Thermal Properties
| Property | Value | Units | Notes |
|---|---|---|---|
| Melting Point | 1,510 | °C | Pure iron base |
| Sintering Temperature | 1,120-1,150 | °C | Typical production range |
| Coefficient of Thermal Expansion | 11-13 | 10⁻⁶/°C | @ 20-200°C |
| Thermal Conductivity | 25-35 | W/(m·K) | Lower than wrought (porosity) |
| Specific Heat | 450-480 | J/(kg·K) | @ room temperature |
Thermal Processing Recommendations:
- Sintering atmosphere: Dissociated ammonia, nitrogen-hydrogen, or vacuum
- Cooling rate: <100°C/min to avoid cracking
- Annealing (stress relief): 550-650°C for 1-2 hours
Corrosion Resistance
Performance in Various Environments
| Environment | Corrosion Rate | Rating | Protection Methods |
|---|---|---|---|
| Indoor Dry Air | <0.5 µm/year | ✅ Excellent | None required |
| High Humidity (85% RH) | 5-15 µm/year | ⚠️ Fair | Oil coating recommended |
| Salt Spray (5% NaCl) | 50-150 µm/year | ❌ Poor | Plating or coating required |
| Industrial Atmosphere | 10-25 µm/year | ⚠️ Fair | Oil, paint, or phosphate coating |
| Automotive Underbody | 20-50 µm/year | ⚠️ Fair | Electroplating (Zn, Ni) essential |
Corrosion Protection Options:
- Steam Treatment - Black oxide (Fe₃O₄) layer, fills surface pores → +50-70% corrosion resistance
- Oil Impregnation - Fills porosity with rust-preventive oil → +100-150% resistance
- Electroplating - Zinc, nickel, or chromium plating → +10-20× resistance
- Resin Impregnation - Epoxy fills pores, seals surface → +200-400% resistance
- Powder Coating - Organic coating after resin seal → Maximum protection
Note: Copper content provides modest galvanic protection but insufficient for harsh environments.
Machinability & Secondary Operations
Machining Characteristics
| Operation | Machinability Rating | Recommended Tools | Feed/Speed |
|---|---|---|---|
| Turning | 80-90% of B1112 steel | Carbide, HSS | 120-180 m/min (carbide) |
| Drilling | 75-85% of B1112 | Carbide-tipped drills | 0.15-0.25 mm/rev feed |
| Tapping | 70-80% of B1112 | Form taps preferred | Cutting oil essential |
| Grinding | Good | Aluminum oxide wheels | Standard parameters |
| Broaching | Fair to Good | HSS broaches | Lower speeds recommended |
Machinability Factors:
- ✅ Copper content improves chip breaking and tool lubrication
- ✅ Lower hardness (as-sintered) enables easier machining than heat-treated
- ⚠️ Porosity causes abrasive tool wear (tool life 60-80% of wrought steel)
- ⚠️ Interconnected porosity can absorb cutting fluids (use minimal flood cooling)
Cost-Saving Tip: Design parts to minimize secondary machining. Every machined feature adds $0.10-$0.50 per part cost.
Design Guidelines for FC-0208
Optimal Design Features
✅ Good Design Practices:
- Cylindrical or prismatic shapes with uniform wall thickness
- Gears with straight or helical teeth (helix angle <15°)
- Holes parallel to pressing direction (cored during compaction)
- Chamfers and radii along pressing axis (no sharp corners)
- Wall thickness 2.0-8.0 mm (thinner requires higher density)
❌ Design Challenges:
- Undercuts perpendicular to pressing direction (require machining)
- Internal threads (must be tapped after sintering)
- Very thin walls <1.5 mm (risk cracking, low fill density)
- Large flat areas (prone to density variation)
- Sharp internal corners (stress concentrations with porosity)
Recommended Design Tolerances
| Feature Type | Achievable Tolerance | Notes |
|---|---|---|
| Outer Diameter | ±0.08 - 0.12 mm | After sizing operation |
| Inner Diameter | ±0.10 - 0.15 mm | Cored holes, better than drilled |
| Length/Height | ±0.10 - 0.20 mm | Perpendicular to pressing direction |
| Flatness | 0.05 - 0.10 mm | On faces perpendicular to pressing |
| Parallelism | 0.08 - 0.15 mm | Between pressed faces |
| Concentricity | 0.10 - 0.20 mm | Between OD and ID |
Tighter Tolerances Available:
- Sizing operation improves OD/ID to ±0.03-0.05 mm (adds $0.15-$0.30/part)
- Grinding achieves ±0.01-0.02 mm (adds $0.50-$1.50/part)
Applications & Case Studies
Common Applications
Automotive Industry:
- Transmission gears (spur, helical <15°)
- Oil pump rotors and gears
- Small engine connecting rods (lower-stress variants)
- Synchronizer hubs
- Structural brackets and mounts
Power Tools:
- Planetary gear carriers
- Motor mounts and brackets
- Clutch components
- Drive gears
Industrial Machinery:
- Conveyor system gears
- Actuator components
- Lock mechanisms
- Cam followers and bushings
Small Engines (Lawn & Garden):
- Camshafts
- Rocker arms
- Crankshaft gears
- Governor components
Case Study: Automotive Transmission Gear
Application: 3-speed automatic transmission parking gear Requirements:
- Tensile strength >450 MPa
- Hardness 75-85 HRB
- Gear tooth profile tolerance ±0.08 mm
- Cost target <$2.50/part (100K volume)
Solution: FC-0208 Material Selection
- Density: 7.1 g/cm³ (90% theoretical)
- Condition: As-sintered (no heat treatment)
- Cycle time: 18 seconds per part
Results:
- ✅ Achieved tensile strength: 465 MPa
- ✅ Hardness: 78 HRB (specification met)
- ✅ Dimensional accuracy: ±0.10 mm (within tolerance)
- ✅ Production cost: $2.15/part (15% under target)
- ✅ Zero secondary machining required (near-net-shape)
Cost Comparison:
- Forged + machined alternative: $6.80/part
- Savings: $464,000/year at 100K volume (68% cost reduction)
Cost Analysis
Material & Processing Costs (Estimated USD per Part, 50K Volume)
| Cost Component | 6.8 g/cm³ | 7.1 g/cm³ | 7.4 g/cm³ |
|---|---|---|---|
| Raw Powder | $0.80 | $0.95 | $1.10 |
| Compaction | $0.40 | $0.45 | $0.55 |
| Sintering | $0.30 | $0.30 | $0.35 |
| Sizing (optional) | +$0.20 | +$0.20 | +$0.20 |
| Heat Treatment (optional) | +$0.50 | +$0.60 | +$0.70 |
| Steam Treatment (optional) | +$0.08 | +$0.08 | +$0.10 |
| Total (as-sintered) | $1.50 | $1.70 | $2.00 |
| Total (with HT) | $2.00 | $2.30 | $2.70 |
Tooling: $15,000-$40,000 (500K-2M part life) = $0.01-$0.08/part amortized
Quality Control & Testing
Standard QC Tests
| Test | Frequency | Specification | Method |
|---|---|---|---|
| Density | Every batch | ±0.05 g/cm³ of target | MPIF 42 (Archimedes) |
| Tensile Strength | 1 per 5,000 parts | Per specification table | MPIF 10 |
| Hardness | 1 per 1,000 parts | ±5 HRB of target | ASTM E18 (Rockwell) |
| Dimensional | 1 per 500 parts | Per drawing tolerances | CMM or optical |
| Microstructure | Weekly | Porosity rating 1-4 | Metallographic section |
Material Certifications Available:
- Chemical composition analysis (C, Cu, Fe)
- Mechanical property test reports
- Dimensional inspection reports (FAI)
- Traceability to powder lot numbers
Storage & Handling
Material Storage Guidelines
Powder Storage:
- Keep containers sealed to prevent moisture absorption
- Store in cool, dry environment (<30°C, <50% RH)
- Shelf life: 12 months (powder), 24 months (sintered parts)
- Avoid contamination with other powders or foreign materials
Finished Part Storage:
- Oil-treated parts: store in dry conditions, no special packaging
- Untreated parts: apply rust-preventive oil or VCI bags
- Stacking: use separators to prevent surface damage
- Shelf life: Indefinite (with proper corrosion protection)
Get FC-0208 Material Expertise
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✅ Free Material Consultation - Density and heat treatment recommendations ✅ Property Predictions - Expected strength/hardness for your design ✅ Cost Optimization - Balancing performance vs. processing costs ✅ Design Review - Manufacturability assessment for FC-0208 production
Request FC-0208 Engineering Support →
Response Time: Material recommendations within 24 business hours Testing: MPIF-standard test reports available for all production lots
Internal Links
- FC-0205 Material Properties - Lower carbon variant for ductility
- FN-0405 High-Strength Material - Nickel-strengthened alternative
- Powder Metallurgy Material Selection Guide - Compare all PM material options
- Automotive PM Applications - FC-0208 success stories in automotive
- Powder Metallurgy Process Guide - How FC-0208 parts are manufactured
Frequently Asked Questions
What's the difference between FC-0205 and FC-0208 materials?
FC-0205 contains 0.5% combined carbon vs. 0.8% in FC-0208. This makes FC-0205 slightly lower strength (350-420 MPa) but better for applications requiring cold forming or high ductility. FC-0208 offers 15-20% higher strength and better hardenability for heat-treated components.
Can FC-0208 be welded?
Not recommended. Powder metallurgy parts contain interconnected porosity that causes welding defects (porosity, cracking). For assemblies, use mechanical fastening, brazing, or adhesive bonding instead.
How does FC-0208 compare to FN-0205 (iron-nickel-copper)?
FN-0205 offers 30-40% higher strength (520-650 MPa) due to nickel addition but costs 25-35% more. Choose FN-0205 for high-stress applications (connecting rods, high-torque gears). FC-0208 suits cost-sensitive, medium-stress applications.
What surface treatments improve corrosion resistance?
Best options: (1) Steam treatment + oil impregnation for indoor use, (2) Zinc electroplating for automotive underbody, (3) Resin impregnation + powder coating for maximum protection. Steam treatment alone provides 50-70% improvement at minimal cost.
Can FC-0208 be used for bearings?
Yes, with modifications. Use lower density (6.6-6.8 g/cm³) for self-lubricating bushings where porosity retains oil. Add oil impregnation (10-15% oil by weight) for improved bearing performance. Not suitable for high-speed or high-load bearings (use bronze PM alloys instead).
Related Resources
Use these internal links to keep moving through the most relevant guides, service pages, and technical references for this topic.
FC-0205 Material Guide
Compare FC-0208 with a lower-carbon FC-series material when balancing strength, wear, and cost.
Materials Overview
See where FC-0208 fits within broader FC-, FN-, stainless, and bearing material families.
Hydraulic Pump Gears
Review one application where FC-0208 can be practical depending on pressure target and finishing route.
Request a Quote
Send your drawing and duty condition for FC-0208 material review and quotation support.