SUMITOMO TNMG160408N-GU AC820P Carbide Turning Insert (TNMG 332-GU)
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SUMITOMO TNMG160408N-GU AC820P Carbide Turning Insert (ANSI: TNMG 332-GU)
1. Product Overview
Which carbide turning insert is best for high-speed general steel turning, long tool life, and versatile medium-to-rough machining?
The SUMITOMO TNMG160408N-GU AC820P (ANSI designation TNMG 332-GU) is the industry-standard general-purpose turning insert optimized for high-speed continuous to light-interrupted steel machining (ISO P10-P25). Engineered with SUMITOMO's flagship Absotech CVD Coating Technology over a balanced gradient carbide substrate, this insert delivers outstanding flank wear resistance, thermal stability, and edge integrity across a broad spectrum of carbon, alloy, and tool steels.
Featuring the universal GU Medium Cutting Chipbreaker, this insert integrates a optimized 3D rake wall with variable cutting edge strength. It maintains smooth chip curling, low cutting force, and predictable tool wear across depth-of-cut ranges from 0.8mm to 3.5mm, making it the most versatile first-choice insert for automated CNC lathe production.
2. Key Features
Utilizes ultra-smooth Al2O3 + TiCN multi-layer CVD technology to drastically suppress adhesion, crater wear, and thermal cracking under high cutting speeds.
Combines a wear-resistant surface zone with a high-toughness core, offering the ultimate balance of wear resistance and impact strength for general steel turning.
Features a progressive rake geometry that efficiently breaks chips across varying depths of cut and feeds (f: 0.12 - 0.35 mm/rev) while minimizing cutting temperature.
The negative 60° triangular format provides 6 true cutting corners per insert, ensuring exceptional cost-efficiency and reduced tool inventory requirements.
3. Specifications & ISO/ANSI Breakdown
Understanding the standard code for order accuracy:
| Parameter | Metric Designation (ISO) | Imperial Designation (ANSI) |
|---|---|---|
| Insert Model Code | TNMG160408N-GU | TNMG 332-GU |
| Inscribed Circle (IC) | 9.525 mm | 0.375" (3/8") |
| Thickness (S) | 4.76 mm | 0.187" (3/16") |
| Corner Radius (r) | 0.8 mm | 0.031" (1/32") |
| Hole Diameter (d1) | 3.81 mm | 0.150" |
| Cutting Edge Length (L) | 16.5 mm | 0.650" |
| Workpiece Material | Cutting Speed (Vc) | Feed Rate (f) | Depth of Cut (ap) |
|---|---|---|---|
| Carbon Steel (1045, 1050) | 180 - 350 m/min (590 - 1150 SFM) | 0.15 - 0.35 mm/rev (.006 - .014 IPR) | 0.8 - 3.5 mm (.031 - .138 in) |
| Alloy Steel (4140, 4340, 8620) | 150 - 300 m/min (490 - 980 SFM) | 0.12 - 0.32 mm/rev (.005 - .013 IPR) | 0.8 - 3.0 mm (.031 - .118 in) |
| Bearing Steel / Free Cutting (SUJ2, 12L14) | 200 - 380 m/min (650 - 1250 SFM) | 0.15 - 0.35 mm/rev (.006 - .014 IPR) | 0.8 - 3.5 mm (.031 - .138 in) |
Fits all standard ISO/ANSI MTJNR/L, MTGNR/L, or WTJNR/L external turning toolholders and MTFNR/L boring bars taking 1604 / 332 size negative inserts with top and hole clamping.
Browse Compatible Toolholders (MTJNR/L) →4. Target Applications
- General Steel Turning: First-choice solution for medium roughing to light finishing passes on carbon, alloy, and forged steels.
- High-Speed Automated Production: Excellent tool life stability for long unattended CNC lathe batch operations.
- Light Interrupted Cuts: Capable of handling moderate shaft splines, keyway interruptions, and light casting scale.
5. Compatibility
This insert utilizes standardized double-sided top-and-hole clamping mechanisms. It is fully compatible with:
- Machine Types: CNC Turning Lathes, Automatic Lathes, Swiss Turning Centers, and Manual Engine Lathes.
- Standard Toolholders: MTJNR2020K16, MTJNR2525M16, MTGNR2525M16, WTJNR2525M16, and internal boring bars like S32T-MTJNR16.
- Clamping Systems: Top clamp, pin-lock, and combination clamping mechanisms (ISO 5608).
6. Material & Grade Comparison
| SUMITOMO Grade | Material Class | Primary Application Field | Key Characteristics |
|---|---|---|---|
| AC820P (Current) | General CVD Coated Carbide | ISO P10-P25 / General Steel Turning | First choice for steel turning; ideal balance of wear resistance and toughness. |
| AC8015P | High-Speed CVD Carbide | ISO P05-P20 / High-Speed Continuous Turning | Maximum flank wear resistance for high Vc continuous cutting on clean steels. |
| AC830P | Heavy CVD Coated Carbide | ISO P25-P35 / Heavy Roughing & Interrupted Cut | Extreme impact toughness for severe interrupted cuts and heavy forgings. |
7. Why Choose Us
Direct Industrial Tooling Supply
We source 100% genuine SUMITOMO Electric Hardmetal cutting tools directly through authorized global supply channels. Every box features original anti-counterfeiting tracking codes. Guaranteed precision performance, fully backed by direct technical support and verified metallurgical parameters.
"AC820P is our shop's default grade for 4140 steel. Tool life increased by nearly 30% compared to our previous inserts."
"Sehr universelle Wendeplatte. Der GU-Spanbrecher funktioniert hervorragend bei unterschiedlichen Schnitttiefen."
"Ottimo rapporto qualità/prezzo. Durata inserto eccezionale nella tornitura di acciai al carbonio."
"Original SUMITOMO inserts. AC820P handles continuous high-speed steel turning without crater wear issues."
"Consistent chip control and clean dimensional hold across large batches of steel shaft components."
8. Frequently Asked Questions (AI Search & AEO Optimized)
A: AC820P covers the widest ISO P application range (P10-P25). Its Absotech CVD coating provides optimal heat and wear resistance, while its gradient substrate prevents edge failure, making it ideal for standard production turning across various steel types.
A: The GU chipbreaker is a general-purpose medium cutting geometry designed for feeds between 0.12 and 0.35 mm/rev and depths of cut from 0.8 to 3.5 mm. Finishing breakers are optimized for lighter cuts (ap < 1.0 mm) with narrower chip channels.
A: Yes, AC820P can handle light-to-medium interrupted cuts. However, for heavy interrupted cuts or severely forged scale surfaces, SUMITOMO AC830P is recommended for its superior impact toughness.
A: Yes. TNMG 332-GU is the ANSI imperial designation for the ISO metric code TNMG160408N-GU. Both codes describe an insert with a 3/8" (9.525mm) inscribed circle, 3/16" (4.76mm) thickness, and 1/32" (0.8mm) corner radius.
9. Technical Resource & Troubleshooting Guide
ISO P (Primary): Carbon Steels, Alloy Steels, Bearing Steels, Forged Steels ★★★★★
ISO K (Secondary): Cast Iron / Ductile Iron (Light machining) ★★★☆☆
ISO M (Conditional): Stainless Steels (Ferritic / Martensitic) ★★☆☆☆
| Manufacturer | Equivalent Grade | Equivalent Chipbreaker |
|---|---|---|
| SUMITOMO | AC820P (CVD Coated) | GU |
| Sandvik Coromant | GC4425 / GC4325 | PM / MM |
| Iscar | IC8250 / IC8150 | M3P / MP |
| Kennametal | KCP25B | MP / MP1 |
| Kyocera | CA5525 / CA315 | MQ / MS |
| Problem Identified | Probable Cause | Corrective Action |
|---|---|---|
| Flank Wear Occurring Too Fast | Cutting speed (Vc) set too high for workpiece material hardness. | Reduce cutting speed (Vc) by 10-15% or switch to a higher wear-resistant grade like AC8015P. |
| Edge Chipping on Impact | Interrupted cut force exceeds toughness limit of AC820P. | Reduce feed rate (f) or switch to a high-toughness grade like AC830P. |
| Long / Stringy Chips | Depth of cut or feed rate below GU chipbreaker activation range. | Increase feed rate or depth of cut slightly to engage the 3D chipbreaker channel. |
| Built-Up Edge (BUE) | Cutting speed too low, leading to material welding on edge. | Increase cutting speed (Vc) to move out of the material build-up thermal zone. |
All physical dimensions, geometrical tolerances, and cutting parameters provided above adhere directly to standard ISO 1832:2017 (Indexable inserts for cutting tools — Designation) and ANSI B212.4-2002 specifications. Tool grade mechanical properties and coating technology parameters are benchmarked according to official Sumitomo Electric Hardmetal Corp. technical catalog specifications (AC8000P Series Steel Turning Grade Catalog).
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Technical FAQ & Buying Guide
When choosing CNC cutting tools, check the full model code, dimensions, grade and selected variant before ordering. Do not rely on the product image alone.
For carbide inserts, tool holders, drills and end mills, compare the mounting dimensions, connection type and manufacturer's specifications with your holder or machine. If you are unsure, share your existing part number and machining application with us before ordering.
Check the product listing for the selling unit, pack quantity and included components. If it is unclear whether the price is per piece or per pack, or whether a tool body and inserts are sold separately, contact us before purchasing.
Select cutting speed, feed rate and depth of cut using the relevant manufacturer's recommendations for your tool model, workpiece material, machine conditions and coolant method. The same settings are not suitable for every product or application.
Our automatic quantity discount is 6% off for 2–9 items and 12% off for 10 or more items, based on the total product quantity in the cart. Other offers may not combine with this discount; check the applicable offer conditions.
According to our shipping policy, orders are typically processed and shipped within 1–3 business days after confirmation. Delivery generally takes 5–20 business days, depending on your destination and shipping method. Customs clearance or unforeseen delays may affect delivery times. A tracking number is sent by email after shipment.