Inconel 718 is a nickel-chromium-based superalloy known for its excellent strength, corrosion resistance, and high-temperature performance — but it is notoriously difficult to machine due to its mechanical and metallurgical properties.
Machinability Characteristics of Inconel 718
| Property | Impact on Machining |
| High strength (even at elevated temperatures) | Increases tool wear and cutting forces |
| Work hardening tendency | Hardens rapidly during cutting, requiring sharp tools and controlled parameters |
| Low thermal conductivity | Heat concentrates at the cutting edge, accelerating tool wear |
| Abrasive microstructure (e.g., carbides) | Damages cutting tools and limits tool life |
| Toughness and ductility | Makes chip control difficult and can cause built-up edge formation |
Best Practices for Machining Inconel 718
| Recommendation | Details |
| Use of carbide or ceramic tools | Preferably coated grades like TiAlN or CVD-coated carbides |
| Low cutting speeds | Typically 20–30 m/min for roughing, even lower for finishing |
| High feed rates | Helps minimize work hardening; use aggressive but stable feeds |
| Rigid setups | Prevents vibration and tool chatter, critical for surface finish and accuracy |
| Coolant usage | High-pressure, flood coolant to reduce heat buildup and flush chips |
| Tool path optimization | Use of constant engagement (e.g., trochoidal milling) and advanced CAM strategies |
| Tool wear monitoring | Frequent inspection or in-process monitoring to avoid catastrophic tool failure |
Recommended Cutting Parameters for Inconel 718 (Roughing & Finishing)
Here is a recommended cutting parameters table for Inconel 718 machining to help you plan your manufacturing process (units: ISO standard / metric):
1. Turning
| Operation | Tool Type | Cutting Speed Vc (m/min) | Feed Rate f (mm/rev) | Depth of Cut ap (mm) |
| Rough Turning | Carbide (TiAlN coated) | 20–40 | 0.2–0.4 | 1.5–3.0 |
| Finish Turning | Carbide (PVD coated) | 10–25 | 0.05–0.2 | 0.2–1.0 |
🔹 Use high-pressure coolant to maintain stable tool temperature
🔹 Use positive rake angle tools to reduce cutting forces
2. Milling
| Operation | Tool Type | Cutting Speed Vc (m/min) | Feed per Tooth fz (mm/tooth) | Depth of Cut ap (mm) |
| Rough Milling | Carbide end mills | 20–35 | 0.05–0.15 | 0.5–2.0 |
| Finish Milling | Finishing inserts | 8–15 | 0.02–0.08 | 0.2–0.5 |
🔹 Use small diameter, multi-flute tools
🔹 For multi-axis machining, trochoidal tool paths reduce heat load
3. Drilling
| Hole Diameter | Tool Type | Cutting Speed Vc (m/min) | Feed Rate f (mm/rev) |
| Ø < 10 mm | Carbide drill | 8–12 | 0.03–0.08 |
| Ø 10–20 mm | Coated drill | 10–20 | 0.05–0.15 |
| Ø > 20 mm | Re-sharpened drill | 8–15 | 0.1–0.2 |
🔹 Use pilot holes to improve accuracy
🔹 For hole depth >3x diameter, use peck drilling to clear chips
4. Tapping
| Operation | Tool Recommendation | Cutting Speed Vc (m/min) |
| Manual Tapping | High-strength cobalt taps | < 5 |
| Machine Tapping | Adequate cooling + low speed | 3–6 |
⚠ Tapping is challenging; consider thread milling or cold forming instead of conventional tapping
Additional Recommendations
Tool materials: PVD coated carbide (e.g., GC1115), ceramic tools for high-speed finishing
Coolant: Water-soluble or emulsion coolant, high-pressure system ≥70 bar recommended
Tool wear monitoring: Use machine tool monitoring systems or manual inspections; replace tools or inserts per batch
EN 
DE 
RU 
FA 
ID 
ES 
FR 
NL