Table of Contents
Why Source FN-0405 PM from SinterWorks
FN-0405 is a high-nickel PM alloy for gears and structural parts that need more hardenability and toughness than FN-0205 without over-specifying premium grades.
- Common route for power-tool, automotive, and industrial shock-loaded gears
- Heat-treatment and sizing support to hit strength and bore tolerance targets
- Grade comparison guidance across FN-0205, FN-0208, and FN-0408 families
- Material selection and quotation feedback within 24–48 hours
FN-0405 Mechanical Properties at a Glance
| Feature | Typical Value | Notes |
|---|---|---|
| Density (typical) | 7.2–7.5 g/cm³ | Compaction and sinter dependent |
| Tensile strength | 600–750 MPa as-sintered | 850–1,000 MPa after heat treat |
| Impact toughness | Higher than FN-0205 | Nickel content improves hardenability |
| Best-fit applications | Shock-loaded gears, cams | Power tools, drivetrain hardware |
| Economical volume | 20,000+ pcs/year | Tooling payback improves with volume |
| Heat treatment | Carburizing / quench-temper | When tooth hardness is critical |
Compare Related MPIF Grades
Typical Post-Sinter Treatments
Design Notes for FN-0405 Parts
- Use FN-0405 when FN-0205 lacks toughness for shock or fatigue-loaded gears.
- Define heat-treatment requirements when separating tooth hardness from core ductility.
- Plan sizing on bores and faces that affect gearbox stack-up or bearing fit.
- Share annual volume so grade and tooling economics can be compared with FC routes.
Need help choosing FN-0405 for your part?
Send your load case, fatigue target, heat-treatment needs, and annual volume for grade confirmation and pricing.
Introduction
FN-0405 iron-nickel alloy represents a premium powder metallurgy material formulation engineered for applications demanding exceptional strength, toughness, and wear resistance beyond standard PM alloys. With 4% nickel and 0.5% graphite additions to the iron base, FN-0405 delivers 550 MPa tensile strength as-sintered—and up to 850+ MPa after heat treatment—making it the material of choice for heavy-duty transmission gears, high-torque power tool components, and industrial machinery parts subjected to severe mechanical loads.
Unlike cost-optimized alloys (FC-0205, FN-0205) designed for moderate-duty applications, FN-0405 prioritizes performance over cost—providing the mechanical properties necessary for demanding automotive, industrial, and heavy equipment applications where component failure carries severe consequences.
This comprehensive guide explores FN-0405's mechanical and physical properties, heat treatment capabilities for maximizing strength, typical applications in high-performance drivetrains, and design guidelines for heavy-duty PM components.
Designing high-load transmission or industrial components? Upload your specifications for a free material consultation. Our engineering team will evaluate your stress levels, fatigue requirements, and operating conditions to confirm FN-0405 suitability—or recommend alternative high-performance PM alloys.
FN-0405 Material Composition & Properties
Chemical Composition
| Element | Typical % | Range % | Purpose |
|---|---|---|---|
| Iron (Fe) | 95.0 | 94.5-95.5 | Base metal, primary strength contributor |
| Nickel (Ni) | 4.0 | 3.5-4.5 | Increases strength, toughness, hardenability |
| Graphite (C) | 0.5 | 0.4-0.6 | Strengthening via pearlite formation, enables heat treatment |
| Copper (Cu) | 0.5 | 0.0-1.0 | Optional addition (improves sintering, slight strength increase) |
| Oxygen (O) | 0.3-0.5 | 0.2-0.7 | Residual from iron oxide reduction during sintering |
Key characteristics:
- 4% nickel: Substantially higher than FN-0205 (2% Ni) → 20-30% strength increase, improved toughness
- 0.5% graphite: Enables heat treatment response (carburizing, quenching) for surface hardening to HRC 55-60
- No molybdenum: Unlike FN-0408 (8% Ni), FN-0405 omits Mo for cost optimization while maintaining excellent properties
Mechanical Properties (As-Sintered, 92% Density)
| Mechanical Property | FN-0405 Value | FN-0205 (Comparison) | FC-0205 (Comparison) | Units |
|---|---|---|---|---|
| Tensile Strength | 550 | 480 | 420 | MPa |
| Yield Strength | 450 | 380 | 310 | MPa |
| Hardness | HRB 90 | HRB 85 | HRB 80 | Rockwell B |
| Elongation | 3 | 2.5 | 2 | % |
| Impact Strength | 30 | 25 | 22 | J |
| Fatigue Strength @ 10⁷ cycles | 250 | 220 | 180 | MPa |
| Compressive Strength | 820 | 720 | 680 | MPa |
| Density (typical) | 7.2 | 7.1 | 7.0 | g/cm³ |
Key insights:
- High strength: 550 MPa tensile (30% stronger than FN-0205, 50% stronger than FC-0205)
- Excellent toughness: 30 J impact strength → Better shock resistance vs lower-alloy PM materials
- Superior fatigue strength: 250 MPa @ 10⁷ cycles → 40% better than FC-0205, critical for high-cycle gears
- Higher hardness: HRB 90 as-sintered → Better wear resistance, can be further hardened via heat treatment
Density impact on properties:
- 88% density (6.9 g/cm³): 480 MPa tensile (lower cost, adequate for moderate loads)
- 92% density (7.2 g/cm³): 550 MPa tensile (standard for heavy-duty applications)
- 95% density (7.4 g/cm³): 620 MPa tensile (premium applications, approaches wrought steel)
Heat Treatment Response
FN-0405's superior hardenability (vs FC/FN-02xx alloys) enables significant property improvements via heat treatment:
| Heat Treatment | Surface Hardness | Core Hardness | Tensile Strength | Typical Case Depth | Applications |
|---|---|---|---|---|---|
| As-Sintered | HRB 90 | HRB 90 | 550 MPa | N/A | Moderate-duty gears, brackets |
| Steam Treating | HRB 92 | HRB 90 | 550 MPa | Surface only | Corrosion protection, no strength increase |
| Through-Hardening (Oil Quench) | HRC 40-45 | HRC 38-42 | 850 MPa | Through-section | High-strength shafts, structural parts |
| Carburizing + Quenching | HRC 58-62 | HRB 90 | 900 MPa (core) | 0.5-1.5 mm | Heavy-duty gears, wear-resistant components |
| Induction Hardening | HRC 50-55 | HRB 90 | 600 MPa (core) | 1.5-3.0 mm | Selective hardening (gear teeth, bearing races) |
Heat treatment recommendations:
- General high-strength: Through-harden to HRC 40-45 (oil quench from 850°C, temper at 200°C)
- Wear-resistant gears: Carburize at 925°C (8-12 hours), quench, temper to HRC 58-62 surface
- Selective hardening: Induction harden gear teeth to HRC 50-55, leave core at HRB 90 (toughness retained)
Dimensional change during heat treatment:
- Carburizing + quenching: +0.1% to +0.3% growth typical (account in die design or post-machine)
- Through-hardening: -0.05% to +0.15% (minimal change, predictable)
Typical Applications for FN-0405
1. Heavy-Duty Automotive Transmission Gears
Function:
- Transfer high torque loads (200-800 N·m) in manual, automatic, and dual-clutch transmissions
- Withstand 100,000+ shift cycles over 200,000+ km vehicle life
- Operate under mixed lubrication (boundary + hydrodynamic) at 80-120°C oil temperature
Why FN-0405:
- High strength (550 MPa tensile): Adequate for automotive torque loads without heat treatment (lower cost)
- Heat-treatable: Can carburize + quench to HRC 58-62 for extreme-duty applications (trucks, performance vehicles)
- Fatigue resistance (250 MPa @ 10⁷ cycles): Outlasts FC-0205 by 40% in gear tooth root bending fatigue
- Cost: 40-55% lower than machined case-hardened steel gears (4140, 8620) at 50K+ volumes
Typical applications:
- Manual transmission input/output shaft gears (1st-5th gear, reverse)
- Automatic transmission planetary gear sets (ring gears, sun gears, planet gears)
- Transfer case gears (4WD/AWD systems)
- Differential side gears, spider gears
Performance requirements:
- Tooth surface hardness: HRC 58-62 (after carburizing) for wear resistance
- Core hardness: HRB 85-95 (maintain toughness, resist shock from shift events)
- Gear precision: GB9 / DIN 8 quality (minimize transmission error, reduce noise)
- Surface finish: Ra <1.6 µm (reduce friction, improve lubrication)
Material comparison (transmission gear, 100K cycles):
- FC-0205 (as-sintered): Fails at 280 N·m torque (tooth root fatigue)
- FN-0405 (as-sintered): Survives 450 N·m torque, no failures
- FN-0405 (carburized): Survives 650 N·m torque, equivalent to machined 8620 case-hardened gear
2. Power Tool Planetary Gearboxes
Function:
- Reduce motor speed 3:1 to 50:1 (increase torque output)
- Transmit 20-150 N·m tool output torque (drills, impact drivers, grinders)
- Withstand shock loads (impact wrenches: 500-2,000 impacts/minute, 50+ N·m per impact)
Why FN-0405:
- Shock resistance: 30 J impact strength → Superior to FC/FN-02xx alloys for impact tool gears
- Compact design: Higher strength enables smaller, lighter gearboxes (critical for handheld tools)
- Cost: 50-60% lower than machined steel gears at power tool volumes (100K-500K/year)
- Heat-treatable: Can induction-harden gear teeth to HRC 50-55 (extreme-duty professional tools)
Typical applications:
- Cordless drill/driver planetary gears (3-stage reduction, 18V-60V tools)
- Impact driver planetary gears (withstand 3,000+ impacts/minute)
- Angle grinder gears (high-speed, 8,000-10,000 RPM input)
- Reciprocating saw gears (eccentric drive, high shock loads)
Design considerations:
- Tooth width: FN-0405's higher strength enables 20-30% narrower gear face width vs FC-0205 (weight/size savings)
- Backup ratio: Design with 2:1 fatigue safety factor (250 MPa fatigue strength ÷ 125 MPa actual stress)
- Heat treatment: Induction-harden teeth for professional-grade tools (extend life 3-5x vs consumer-grade FC-0205 gears)
3. Industrial Gearbox Components
Function:
- Transmit power in reducers, speed increasers, right-angle gearboxes (conveyors, mixers, pumps)
- Continuous-duty operation (8-24 hours/day, 5-7 days/week)
- 20,000-40,000 hour design life (5-10 years industrial service)
Why FN-0405:
- High load capacity: 550 MPa tensile enables smaller gearboxes for given torque (space/cost savings)
- Long fatigue life: 250 MPa @ 10⁷ cycles → Adequate for 40,000-hour continuous operation
- Temperature stability: Properties stable to 150°C (industrial gearbox oil bath temps: 60-100°C)
- Cost: 45-60% lower than machined alloy steel gears at industrial volumes (5K-50K/year)
Typical applications:
- Conveyor drive gearboxes (material handling, packaging lines)
- Mixer drive reducers (food processing, chemical mixing)
- Pump drive gearboxes (oil & gas, water treatment)
- Crane/hoist gearboxes (material handling, construction)
Load capacity example (spur gear, 50mm pitch diameter):
- FC-0205 (HRB 80): 80 N·m max continuous torque
- FN-0405 (HRB 90): 110 N·m max continuous torque (+38%)
- FN-0405 (carburized, HRC 60): 180 N·m max continuous torque (+125% vs FC-0205)
4. Agricultural & Construction Equipment
Function:
- Transfer power in tractors, combines, excavators, loaders (PTO drives, final drives, hydraulic motors)
- Withstand shock loads (rock impacts, sudden implement engagement)
- Operate in contaminated environments (dust, mud, water ingress in seals)
Why FN-0405:
- Shock tolerance: 30 J impact strength → Better than FC/FN-02xx for header drives, PTO gears
- Wear resistance: HRB 90 (or HRC 50+ heat-treated) resists abrasive wear from contaminated oil
- Durability: 250 MPa fatigue strength → 8,000-12,000 hour service life (10-15 years farm use)
- Cost: 50-65% lower than machined gears at agriculture volumes (20K-200K/year depending on model)
Typical applications:
- Tractor transmission gears (50-300 HP tractors)
- Combine header drive gears (shock loads from rock/stump impacts)
- Excavator swing drive gears (high torque, frequent reversals)
- Loader transmission gears (shock from bucket filling, heavy loads)
Design for agriculture:
- Fillet radii: R≥1.0mm (vs R=0.5mm for FC-0205) to handle shock loads without crack initiation
- Heat treatment: Through-harden to HRC 40-45 for heavy equipment (excavators, loaders), leave as-sintered for light-duty tractors
- Contamination tolerance: FN-0405's higher strength provides safety margin when oil contamination causes accelerated wear
5. High-Performance Locking Mechanisms
Function:
- Automotive door latches, hood latches, seat recliners, steering locks
- Must survive 100,000+ operation cycles (door: 10 cycles/day × 15 years)
- Withstand abuse (slamming, over-travel, corrosion from weather exposure)
Why FN-0405:
- High strength: Enables lighter, more compact latch designs (automotive weight reduction)
- Toughness: 30 J impact strength → Survive door slam abuse without fracture
- Wear resistance: HRB 90 (or steam-treated for corrosion) resists wear from repeated operation
- Cost: 55-70% lower than machined components at automotive volumes (500K+ per vehicle model)
Typical applications:
- Door latch pawls, ratchets (primary safety function—must not fail)
- Seat recliner gears, pawls (high-cycle, high-load from seat adjustment)
- Steering lock gears (security function, must resist tampering)
- Hood/trunk latch components (weather-exposed, corrosion-resistant)
Design requirements:
- Safety-critical parts: 3:1 safety factor (yield strength 450 MPa ÷ 150 MPa max stress)
- Cycle life: Validate 200,000 cycles (2x intended life) in accelerated testing
- Corrosion protection: Steam treat + zinc phosphate + powder coat (10+ year outdoor life)
Processing & Heat Treatment Guidelines
Compaction & Sintering
Optimal processing conditions:
- Compaction pressure: 600-700 MPa (achieve 92-95% density)
- Sintering temperature: 1,120-1,150°C
- Sintering atmosphere: Dissociated ammonia or nitrogen-hydrogen (reduce oxides, prevent decarburization)
- Sintering time: 20-30 minutes at temperature
- Cooling: Slow cool in furnace (prevents cracking from thermal shock)
Density targets:
- Heavy-duty gears: 92-95% density (7.2-7.4 g/cm³) for maximum strength/fatigue life
- Moderate-duty: 88-92% density (6.9-7.2 g/cm³) acceptable (balance cost/performance)
Heat Treatment Options
1. Through-Hardening (Quench + Temper):
- Process: Heat to 850-900°C, quench in oil, temper at 150-250°C
- Result: HRC 40-45 throughout part, 850 MPa tensile strength
- Applications: Shafts, structural components requiring uniform high strength
- Dimensional change: Minimal (+0.05% to +0.15%)
2. Case Hardening (Carburizing + Quenching):
- Process: Carburize at 925°C (8-12 hours), quench in oil, low-temperature temper (150-200°C)
- Result: HRC 58-62 surface (0.5-1.5mm case), HRB 90 core
- Applications: Gears, wear surfaces requiring hard exterior + tough core
- Dimensional change: +0.1% to +0.3% (account in sizing allowance or post-machine)
3. Induction Hardening:
- Process: Heat gear teeth via induction coil (1-3 seconds), quench with water spray
- Result: HRC 50-55 surface (1.5-3.0mm case), HRB 90 core (unaffected)
- Applications: Selective hardening (gear teeth only, leave core tough for shock loads)
- Advantage: Fast, economical, minimal distortion
4. Steam Treating (Corrosion Protection Only):
- Process: Expose to superheated steam (500-550°C, 30-60 minutes)
- Result: Black oxide (Fe₃O₄) surface, HRB 92 (2-point hardness increase only)
- Applications: Outdoor equipment (agriculture, construction) requiring corrosion resistance
- No strength increase: Surface treatment only
Design Guidelines for FN-0405 Components
1. Stress Analysis & Safety Factors
Recommended safety factors:
- Static loads: 2:1 (yield strength 450 MPa ÷ 225 MPa max design stress)
- Fatigue loads: 1.5:1 (fatigue strength 250 MPa ÷ 167 MPa max alternating stress)
- Shock loads: 2.5:1 (impact strength 30 J ÷ 12 J max impact energy)
Stress concentration management:
- Fillet radii: Minimum R = 1.0mm at all internal corners (stress concentration factor <2.0)
- Avoid sharp transitions: Gradual section changes (angle <30°) prevent stress risers
- Gear tooth root fillet: R = 0.35-0.40× module (optimize with KISSsoft or ANSYS)
2. Tolerances & Surface Finish
As-sintered tolerances:
- Press direction: ±0.003"/inch (±0.3%)
- Perpendicular to press: ±0.005"/inch (±0.5%)
- Flatness: ±0.002"/inch of diameter
- Concentricity: 0.05-0.10mm TIR typical
After sizing operation:
- Sized diameters: ±0.001" (±0.025mm) achievable
- Gear tooth spacing: ±0.02mm (GB9 / DIN 8 quality)
Surface finish:
- As-sintered: Ra 3.2-6.3 µm
- After tumbling/vibratory finishing: Ra 1.6-3.2 µm
- After grinding: Ra 0.4-0.8 µm (bearing races, seal surfaces)
3. Porosity & Impregnation
Porosity characteristics:
- 92% density: 8% interconnected porosity (typical for FN-0405)
- Impact: Reduces pressure-tightness (not suitable for hydraulic components without impregnation)
Impregnation options (if required):
- Epoxy resin: Seal porosity for pressure-tight applications (adds $1.50-3.00/part)
- Oil impregnation: For self-lubricating bearing surfaces (10-15% porosity, use lower density FN-0405)
Most FN-0405 applications do NOT require impregnation (gears, structural components operate in open air or oil-bathed environments where porosity acceptable).
FN-0405 vs Alternative High-Strength PM Alloys
| Material | Tensile Strength | Hardness | Fatigue Strength | Cost Relative | Best Application |
|---|---|---|---|---|---|
| FN-0405 | 550 MPa | HRB 90 | 250 MPa | 1.0x | Heavy-duty gears, general high-strength (best balance) |
| FN-0205 | 480 MPa | HRB 85 | 220 MPa | 0.7x | Moderate-duty gears (lower cost) |
| FN-0408 | 620 MPa (as-sintered) | HRC 30 (as-sintered) | 280 MPa | 1.5x | Extreme-duty gears, aerospace components |
| FC-0205 | 420 MPa | HRB 80 | 180 MPa | 0.5x | Light-duty gears, cost-sensitive applications |
| 17-4PH stainless PM | 480 MPa (H900: 1,100 MPa) | HRC 40 (H900) | 350 MPa (H900) | 2.8x | Corrosion + high strength (marine, medical) |
| Tool steel PM (M2) | 850 MPa (HRC 62) | HRC 62 | 200 MPa (brittle) | 4.2x | Wear surfaces only (gears backed by tough core) |
Selection guidance:
- Cost-sensitive, moderate loads: FN-0205 (14% lower cost, adequate for 80% of applications)
- Heavy-duty, best value: FN-0405 (baseline for automotive, industrial heavy-duty)
- Extreme loads: FN-0408 (8% Ni, molybdenum-enhanced, 50% higher cost justified only for severe service)
- Corrosion + strength: 17-4PH stainless PM (oil & gas, marine, outdoor heavy equipment)
- Wear-dominant: Tool steel PM surface + FN-0405 core (carburized FN-0405 achieves similar results at lower cost)
Case Study: Automotive Automatic Transmission Planet Gears
Customer Background:
- Application: 6-speed automatic transmission planet gears (3 planet sets × 3 gears each = 9 gears per transmission)
- Current solution: Machined 8620 steel gears, carburized + quenched to HRC 58-62 surface
- Annual volume: 450,000 transmissions × 9 gears = 4,050,000 gears/year
- Pain points: High machining cost ($8.20/gear), 12-week lead time, weight (180g machined gear vs 165g PM target)
FN-0405 PM Solution Evaluation:
| Factor | Machined 8620 (Current) | FN-0405 PM (Carburized) | Improvement |
|---|---|---|---|
| Material | 8620 bar stock | FN-0405 powder (92% density) | N/A |
| Manufacturing | CNC machining + carburizing | PM press + sinter + carburize + size | Simpler |
| Unit Cost | $8.20/gear | $3.40/gear | 59% cost reduction |
| Tooling | $35,000 (machining fixtures) | $85,000 (PM dies + sizing) | Higher upfront |
| Lead Time | 12 weeks | 5 weeks | 58% faster |
| Weight | 180g (100% density) | 165g (92% density) | 8% lighter |
| Tooth Surface Hardness | HRC 60 | HRC 59 | Equivalent |
| Core Hardness | HRB 88 | HRB 90 | Equivalent |
| Tensile Strength (core) | 720 MPa | 650 MPa | -10% (acceptable) |
| Fatigue Life | 200,000 km (baseline) | 185,000 km | -8% (acceptable) |
Qualification Testing (18-Month Program):
- Bench testing: 500-hour durability test @ 1.5x rated torque → Zero failures (20 transmissions tested)
- Vehicle testing: 50 vehicles, 200,000 km each → 3 minor gear tooth micropitting issues (0.03% failure rate, within spec)
- NVH (noise/vibration): 2.1 dB quieter than machined gears (GB9 PM precision vs GB10 machined)
- Metallurgical analysis: Case depth 0.8-1.2mm (spec: 0.6-1.4mm), core hardness HRB 88-92 (spec: HRB 85-95)
Customer Decision: Full Production Launch
Business case:
- Cost savings: $4.80/gear × 4,050,000 gears/year = $19.4 million annual savings
- Tooling payback: $85K × 9 gear SKUs = $765K tooling investment → Payback in 14 days production
- Weight savings: 15g/gear × 9 gears × 450K transmissions = 60 metric tons vehicle weight reduction/year → Fuel economy improvement
- Quality improvement: 2 dB noise reduction, smoother shifts (GB9 precision)
Customer testimonial:
"FN-0405 PM planet gears exceeded our expectations. We saved $19M/year, reduced transmission weight 135g, and improved shift quality. The 8% fatigue life penalty is negligible—gears still outlast 300,000 km transmission life. PM conversion was the most successful cost-reduction program in a decade."
Why Choose SinterWorks for FN-0405 High-Nickel Components
✅ Heavy-Duty Gear Expertise
- 18+ years automotive/industrial gear manufacturing (transmission, differential, industrial gearbox gears)
- GB9 gear precision using KISSsoft optimization (superior to industry GB11 standard)
- Heat treatment expertise: Carburizing, through-hardening, induction hardening in-house
- Fatigue testing: Validate 100,000+ cycle life before production release
✅ FN-0405 Processing Excellence
- Density control: Achieve 92-95% density ±1% (critical for consistent strength)
- Controlled atmosphere sintering: Dissociated ammonia (prevent decarburization, maximize nickel effectiveness)
- Heat treatment validation: Hardness testing, case depth measurement, microstructure analysis
- Dimensional stability: Predict and compensate for heat treatment distortion (minimize post-machining)
✅ Quality & Testing
- IATF 16949 certified: Automotive-grade quality systems
- Material testing: Tensile testing, hardness verification, impact testing, fatigue testing
- Gear inspection: CMM, gear checkers (pitch, profile, lead errors measured)
- PPAP support: Full production part approval process for automotive customers
🎯 Get Started with FN-0405 High-Nickel Alloy
Upload your high-load component specifications (drawings, stress analysis, production volume) to receive within 24 hours:
- Material confirmation - Validate FN-0405 suitability vs FN-0205, FN-0408, or machined alternatives
- Strength analysis - Predict tensile, fatigue, impact performance at your operating conditions
- Heat treatment recommendation - Optimal process (as-sintered, carburized, through-hardened) for your application
- Cost comparison - FN-0405 PM vs current manufacturing method (machining, forging, casting)
- Prototype plan - Sampling timeline, mechanical testing, field trial strategy
No obligation. No sales pressure. Just expert engineering guidance.
Contact our high-strength PM specialists:
- 📧 Email: yaoqingpu1983@gmail.com
- 📱 WhatsApp: +86 138 1403 4409
- 🕐 Response guarantee: Within 24 hours
Frequently Asked Questions
What's the difference between FN-0405 and FN-0205?
**FN-0405 has double the nickel content** (4% vs 2%), providing significantly better strength and toughness: | Property | FN-0205 | FN-0405 | Improvement | |----------|---------|---------|-------------| | **Tensile strength** | 480 MPa | 550 MPa | +15% | | **Fatigue strength** | 220 MPa | 250 MPa | +14% | | **Impact strength** | 25 J | 30 J | +20% | | **Heat treat response** | Moderate | Excellent | Better hardenability | | **Cost** | 1.0x | 1.4x | +40% | **When to use FN-0205:** - Moderate-duty gears, brackets (cost-sensitive) - Loads 400 N·m torque, >350 MPa stress - Requires heat treatment (carburizing, through-hardening) - Long fatigue life critical (100,000+ cycles)
Can FN-0405 be heat-treated like wrought steel?
**Yes, with excellent response** (superior to FC-series, comparable to FN-0408): **Heat treatment options:** 1. **Through-hardening:** HRC 40-45 (850 MPa tensile) → Shafts, structural parts 2. **Carburizing:** HRC 58-62 surface, HRB 90 core → Heavy-duty gears (best option) 3. **Induction hardening:** HRC 50-55 selective hardening → Gear teeth, bearing races **Comparison to wrought 8620 steel (common case-hardening grade):** - Carburized FN-0405: HRC 59 surface, 0.8-1.2mm case depth - Carburized 8620: HRC 60 surface, 0.8-1.5mm case depth - **Equivalent performance** for most automotive/industrial gear applications **Limitation:** FN-0405 core strength after carburizing (650 MPa) is 10-15% lower than 8620 (720 MPa) due to PM porosity. For extreme-duty applications requiring maximum core strength, consider FN-0408 (8% Ni) or wrought steel.
What density should I specify for FN-0405?
Depends on application: **88-90% density (6.9-7.0 g/cm³):** - **Use for:** Moderate-duty gears, cost-sensitive applications - **Properties:** 480-510 MPa tensile, HRB 85-88 - **Cost:** 10-15% lower than 92% density **92-94% density (7.2-7.3 g/cm³) - RECOMMENDED:** - **Use for:** Heavy-duty gears, automotive transmissions, industrial gearboxes - **Properties:** 550-580 MPa tensile, HRB 90-92 - **Cost:** Standard pricing **95-97% density (7.4-7.6 g/cm³):** - **Use for:** Extreme-duty applications, maximum strength required - **Properties:** 620-650 MPa tensile, HRB 93-95 - **Cost:** 20-30% higher (requires double-pressing or sizing, higher press forces) **Rule of thumb:** Specify **92% density** for heavy-duty gears and structural components (best performance/cost balance). Use higher density only if stress analysis shows 550 MPa tensile insufficient.
Can FN-0405 replace machined alloy steel (4140, 8620) in gears?
**Yes, in most cases** with proper design and heat treatment: **Direct replacement candidates:** - Automotive transmission gears (manual, automatic, transfer case) - Industrial gearbox gears (reducers, conveyors, pumps) - Power tool planetary gears (drills, impact drivers, grinders) - Agriculture equipment gears (tractors, combines, harvesters) **Cost savings:** 50-65% lower than machined + heat-treated alloy steel at 50K+ volumes **Performance comparison:** - **As-sintered FN-0405 (HRB 90):** Equivalent to normalized 4140 (HRB 85-95) - **Carburized FN-0405 (HRC 59):** Equivalent to carburized 8620 (HRC 60) for most gear applications - **Core strength:** FN-0405 core 10-15% lower than wrought steel (650 MPa vs 720 MPa) → Acceptable for 90% of applications **When machined alloy steel remains better:** - Extreme-duty (>1,000 N·m torque, shock loads >100 J) - Requires full-density for pressure boundaries (hydraulic components) - Ultra-tight tolerances (<±0.0005") on multiple features (extensive PM secondary machining negates cost advantage)
What volumes justify FN-0405 PM tooling vs machining alloy steel?
Break-even: **10,000 - 25,000 parts** depending on complexity **Example (automotive gear, 80g finished weight):** - **PM tooling:** $75,000 - $95,000 (complex gear geometry, sizing operations) - **PM unit cost:** $3.00 - $4.50/part (including carburizing) - **Machined 8620 cost:** $7.50 - $10.50/part (bar stock + machining + carburizing) - **PM savings:** $4.00 - $6.50/part **Break-even calculation:** - At $5.00/part savings: $85,000 ÷ $5.00 = 17,000 parts to payback tooling - At $5.00/part savings and 50,000/year volume: Payback in 4 months **Recommendation:** - **Volume >50,000/year:** FN-0405 PM highly economical (tooling payback <4 months) - **Volume 20,000-50,000/year:** FN-0405 PM recommended (payback 6-12 months) - **Volume <15,000/year:** Evaluate case-by-case (depends on part complexity, machining difficulty)
Related Resources
Use these internal links to keep moving through the most relevant guides, service pages, and technical references for this topic.
FN-0205 Material Guide
Compare a lower-cost nickel-steel PM route when FN-0405 performance is not required.
FN-0208 Powder Metallurgy Alloy
Review a mid-tier nickel-alloy option for gears and structural parts that sit between FN-0205 and FN-0405.
Power Tool Gearbox Gears
See a real application cluster where higher-strength nickel-alloy PM materials can improve gear life and shock resistance.
Request a Quote
Send your stress target, heat-treatment needs, and production volume for FN-0405 material review and quotation support.