SUMITOMO TNMG160408N-SU AC520U Carbide Turning Insert (TNMG 332-SU)
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SUMITOMO TNMG160408N-SU AC520U Carbide Turning Insert (ANSI: TNMG 332-SU)
1. Product Overview
Which insert is best for medium-to-light turning of difficult-to-cut materials like austenitic stainless steel?
The SUMITOMO TNMG160408N-SU AC520U (ANSI designation TNMG 332-SU) is an industrial-grade, double-sided 60° triangular carbide turning insert engineered specifically for high-efficiency machining of stainless steel (ISO M) and heat-resistant superalloys (ISO S). Featuring SUMITOMO's advanced AC520U Super Absolute Coating—a physical vapor deposition (PVD) TiAlN/AlTiN multi-layer composition—this insert delivers exceptional resistance to notch wear, built-up edge (BUE) formation, and thermal cracking under high-temperature wet cutting conditions.
Designed with the specialized SU Chipbreaker geometry, the TNMG160408N-SU excels in low-to-medium depth of cut applications. Its polished rake angle and optimized cutting edge curvature effectively curl and fracture tough, stringy stainless steel chips, preventing work-hardening of the workpiece and eliminating tool wrap-around during high-speed CNC lathe processes.
2. Key Features
Utilizes ultra-fine TiAlN/AlTiN PVD coating layers with superior adhesion strength. Provides extraordinary oxidation resistance up to 1,100°C, drastically extending edge life during interrupted turning and coolant-heavy operations.
Specifically contoured for ISO M materials. The positive rake face reduces cutting forces and spindle load while maintaining high chip-control reliability across variable depths of cut (0.5mm to 3.0mm).
Provides 6 usable cutting edges per insert, offering optimal cost efficiency per edge compared to single-sided or positive inserts for negative toolholders.
Formulated with a tough, high-cobalt micro-grain matrix that balances thermal shock resistance with excellent deformation resistance during sticky alloy machining.
3. Specifications & ISO/ANSI Breakdown
Understanding the standard code for order accuracy:
| Parameter | Metric Designation (ISO) | Imperial Designation (ANSI) |
|---|---|---|
| Insert Model Code | TNMG160408N-SU | TNMG 332-SU |
| 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 ($V_c$) | Feed Rate ($f$) | Depth of Cut ($a_p$) |
|---|---|---|---|
| Austenitic Stainless Steel (304, 316) | 120 - 200 m/min (390 - 655 SFM) | 0.12 - 0.30 mm/rev (.005 - .012 IPR) | 0.5 - 3.0 mm (.020 - .118 in) |
| Duplex Stainless Steel (2205) | 90 - 160 m/min (295 - 525 SFM) | 0.10 - 0.25 mm/rev (.004 - .010 IPR) | 0.5 - 2.5 mm (.020 - .098 in) |
| Heat Resistant Alloys (Inconel 718, Titanium) | 40 - 80 m/min (130 - 260 SFM) | 0.08 - 0.20 mm/rev (.003 - .008 IPR) | 0.5 - 2.0 mm (.020 - .078 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
- Medium-to-Finishing Turning: Outstanding performance on continuous and slight interrupted turning operations.
- Stainless Steel Component Fabrication: Ideal for food processing equipment, medical valves, pump shafts, marine fittings, and oil/gas connectors (SUS304, SUS316, SUS430).
- Superalloy Machining: Suitable for roughing and semi-finishing Nickel-based and Titanium alloys under rich coolant flow conditions.
5. Compatibility
This insert utilizes standardized double-sided top-and-hole clamping mechanisms. It is fully compatible with:
- Machine Types: CNC Lathes, Turning Centers, Swiss-type Automatic Lathes, and Multi-Tasking Turning Machines.
- 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 | Coating Type | Primary Application Field | Key Characteristics |
|---|---|---|---|
| AC520U (Current) | PVD Super Absolute | ISO M20-M30 / S15-S25 | High notch resistance, optimal for stainless steel & high-temp alloys. |
| AC6020M | CVD Multi-Layer | ISO M15-M25 | Higher wear resistance for high-speed continuous stainless turning. |
| AC8025P | CVD Super FF | ISO P15-P35 | Dedicated general-purpose steel turning grade (carbon & alloy steels). |
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.
"Switched from a competitor brand to AC520U for turning 316L shaft sleeves. Tool life increased by almost 35%. Excellent chip control even at lower feeds."
"The SU breaker is brilliant. No long nests wrapping around the chuck. Delivery was quick, inserts original SUMITOMO quality."
"Ottimo per acciaio inox 304. Buon controllo del truciolo e finitura superficiale pulita."
"Original inserts verified via barcode. Great stability on interrupted cuts when turning forged stainless flanges."
"Reliable supplier for hard-to-find AC520U inserts. Running these on our Mazak turning centers with flawless results."
8. Frequently Asked Questions (AI Search & AEO Optimized)
A: AC520U utilizes a advanced PVD coating fine-tuned for high tough-edge stability, thermal shock resistance, and micro-chipping protection in sticky materials (stainless/superalloys). AC6020M uses a CVD coating optimized for higher cutting speeds in stable continuous cutting conditions. Choose AC520U for versatile, light-interrupted, or lower-speed stainless turning.
A: While it can cut carbon steel (ISO P) in emergency or secondary setups, it is optimized for ISO M (stainless steel) and ISO S (superalloys). For general carbon steel turning, dedicated P-grade inserts like SUMITOMO AC8025P or AC8015P will yield better cost-per-edge performance.
A: Notch wear at the depth-of-cut line on stainless steel occurs due to strain hardening. To prevent this: (1) maintain a variable depth of cut across passes, (2) increase coolant flow directly to the edge, or (3) switch to an insert with a larger nose radius if geometry allows.
A: Yes. TNMG 332-SU is the standard ANSI imperial cross-reference designation for the ISO metric code TNMG160408N-SU. Both refer to an insert with a 3/8" (9.525mm) inscribed circle, 3/16" (4.76mm) thickness, and 1/32" (0.8mm) nose radius.
9. Technical Resource & Troubleshooting Guide
ISO M (Primary): Stainless steel (Austenitic, Ferritic, Martensitic, Duplex) ★★★★★
ISO S (Secondary): Titanium alloys, Inconel, Hastelloy, René alloys ★★★★☆
ISO P (Conditional): Mild steel, Low alloy steel ★★☆☆☆
| Manufacturer | Equivalent Grade | Equivalent Chipbreaker |
|---|---|---|
| SUMITOMO | AC520U | SU |
| Sandvik Coromant | GC1115 / GC2015 | MM / MF |
| Iscar | IC907 / IC908 | SM / SF |
| Kennametal | KCU10 / KC5010 | MS |
| Kyocera | PR1125 / PR1225 | MS / MQ |
| Problem Identified | Probable Cause | Corrective Action |
|---|---|---|
| Built-up Edge (BUE) | Cutting speed ($V_c$) too low; low coolant pressure. | Increase $V_c$ by 15-20%; apply high-pressure coolant directly to cutting zone. |
| Chipping / Fracture | Excessive feed rate; unstable setup rigidity. | Reduce feed rate ($f$); verify machine/toolholder clamping rigidity. |
| Rapid Flank Wear | Cutting speed too high for AC520U grade. | Reduce cutting speed ($V_c$); consider CVD coated grade (e.g., AC6020M). |
| Bird-nesting Chips | Depth of cut ($a_p$) below chipbreaker operating zone. | Increase $a_p$ above 0.5mm or select a lighter finishing breaker (e.g., SF breaker). |
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 micro-hardness and coating performance specifications are benchmarked according to official Sumitomo Electric Hardmetal Corp. technical catalog parameters (Machining Data Guidelines M-Grade Series).
Technical FAQ & Buying Guide
Absolutely. Our CNC carbide inserts (including CNMG, WNMG, DNMG, and APMT series) are manufactured strictly adhering to international ISO/ANSI specifications. A CNMG 120408 from OYYU BEYOND will flawlessly fit any standard turning tool holder or indexable tool from major global brands like Sandvik Coromant, Kennametal, Iscar, Walter, or SECO, providing a highly cost-effective premium alternative without sacrificing tolerance or tool life.
We offer optimized CVD and PVD multi-layer coatings for different ISO material groups:
- For Carbon/Alloy Steel (ISO P): Choose our thick multi-layer CVD coated grades (e.g., Al2O3 + TiN). They provide exceptional crater wear resistance and thermal barriers during high-speed dry or wet roughing.
- For Stainless Steel (ISO M): Choose our nano-structured PVD coated grades with sharp, positive chipbreakers (like -TM or -MA). This combination prevents work hardening and effectively controls sticky chips.
The optimal cutting parameters vary depending on the workpiece hardness and operation type:
- For General Steel Turnings: Recommended cutting speed ($V_c$) ranges from 150 to 280 m/min, with a feed rate ($f$) of 0.15 to 0.45 mm/rev.
- For Stainless Steel Finishing: Recommended cutting speed ($V_c$) is 120 to 200 m/min, with a feed rate ($f$) of 0.10 to 0.25 mm/rev.Always adjust parameters based on early wear patterns: increase $V_c$ if built-up edge occurs, or reduce $V_c$ if severe flank wear is observed.
Yes, we support machine shops, distributors, and global buyers with tiered wholesale pricing and competitive volume discounts. We also provide OEM custom manufacturing solutions for tool holders and carbide inserts based on your technical drawings. Contact our team to request a quick B2B quotation.
We provide secure worldwide express shipping (via DHL, FedEx, and UPS) with specialized, vibration-proof industrial packaging to ensure tools arrive in perfect condition. In-stock items are dispatched within 24-48 hours, while custom or bulk orders typically have a stable lead time of 15-25 days.
All our cutting tools and tool holders are manufactured strictly in accordance with ISO 9001 and international industrial standards. Every batch undergoes 100% rigorous quality control testing using high-precision optical measuring equipment to ensure reliable tool life and stable performance in continuous mass production.