Korloy TNMG220408-HM NC3120 (TNMG 432-HM) Large Alloy Steel Insert (10pcs)
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The Original Korloy TNMG220408-HM NC3120 (ANSI: TNMG 432-HM) is a high-performance Large-Format Triangular Insert designed for Alloy and Hardened Steel Machining (P-Group). Utilizing the elite NC3120 CVD Coating, this insert is the industry standard for high-speed, continuous-to-semi-interrupted cutting of large components. The 22mm edge length and HM Chipbreaker provide maximum stability, allowing for aggressive material removal on tough materials like 4140, 4340, and tool steels.
The High-Speed Heavyweight: NC3120 is engineered to handle the intense heat generated when machining large, high-tensile steel parts. Its advanced coating structure prevents crater wear, making it the most cost-effective choice for long-run production in Oil & Gas, Power Generation, and Automotive industries.
Technical Specifications (Metric & Imperial):
| ISO Designation | TNMG 220408-HM |
| ANSI Designation | TNMG 432-HM |
| Inscribed Circle (IC) | 12.7 mm / (1/2") |
| Thickness (S) | 4.76 mm / (3/16") |
| Corner Radius (r) | 0.8 mm / (1/32") |
| Grade | NC3120 (Elite Wear-Resistant CVD) |
Core Performance Benefits:
- Enhanced Thermal Stability: Large 22mm carbide substrate acts as a massive heat sink, protecting the edge during long, heavy cuts.
- Ultra-Smooth CVD Coating: Specialized Al2O3 layer minimizes friction and chip welding at high surface speeds.
- Reinforced HM Geometry: Optimized for medium cutting depths, ensuring excellent chip breaking even on high-strength alloys.
- Exceptional Edge Life: Specifically tuned for steels with hardness levels between HB250-450 (HRC 25-45).
Recommended Cutting Parameters:
| Material Group | Cutting Speed (Vc) | Feed Rate (fn) | Depth of Cut (ap) |
|---|---|---|---|
| High-Tensile Alloy Steel (4140) | 150-280 m/min (490-920 sfm) | 0.15-0.50 mm/rev (.006-.020 ipr) | 1.0-5.5 mm (.040-.217") |
| Pre-hardened Mold Steel (P20) | 100-200 m/min (330-650 sfm) | 0.15-0.40 mm/rev (.006-.016 ipr) | 1.0-4.5 mm (.040-.177") |
Compatible Tooling Systems:
Ensure your holder is designed for TNMG 22-size (4-size ANSI):
- External Heavy Holders: MTJNR 2525M22 / MTJNR 3232P22 (ANSI 16-4D / 20-4E)
- Heavy Boring Bars: S40U-WTJNR22 / S50V-WTJNR22
Machinist Tip: Scaling for Alloy Steels
Why NC3120 makes sense for large parts:
Unmatched Productivity. On 40+ inch shafts or large gear blanks, tool change downtime is expensive. NC3120 is the best grade to ensure you can complete a long pass without the tool wearing out midway.
While NC3020 is great for general carbon steel, it may struggle with the abrasive heat of alloy steels. Choose NC3120 when the material is "tough" rather than just "hard."
Pro Advice: Large workpieces often have surface scale. Use the robust TNMG220408 to get under the scale in the first pass, and let the NC3120 coating handle the high-speed clean-up with confidence.
Packaging: 10 pieces per box.
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