SUMITOMO TNMG160404N-EX AC520U Turning Insert | TNMG331
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1. Product Overview
Looking for the best carbide insert to overcome built-up edge and notch wear when turning duplex, austenitic, or martensitic stainless steel?
The SUMITOMO TNMG160404N-EX AC520U (ANSI: TNMG331N-EX AC520U) is a premium double-sided 60° negative triangular carbide turning insert tailored for medium-to-light continuous and interrupted cutting. Engineered with SUMITOMO's proprietary Absotech® PVD coating technology, grade AC520U combines an ultra-fine carbide substrate with a high-adhesion TiAlN/AlCrN multi-layer coating. This design drastically reduces work hardening, friction, and heat buildup on tough alloys.
Featuring the specialized EX Chipbreaker, this insert features an optimized rake angle and variable wave profile. It guarantees seamless chip evacuation across varying depth-of-cut ranges, eliminating wire-nesting chips and protecting both the workpiece finish and CNC machinery.
ISO / ANSI Designation Breakdown
2. Product Key Features
- Absotech® PVD Coating: Extreme heat resistance and thermal barrier properties preventing thermal cracking during wet or dry turning.
- EX Chipbreaker Geometry: Curved cutting edge reduces cutting resistance by 18%, reducing spindle load and chatter on slender shafts.
- 6 Cutting Edges: Double-sided triangular design delivers optimal cost efficiency per cutting edge.
- Exceptional Notch Resistance: Inhibits notch wear caused by work-hardened layers in 304, 316, and 17-4PH stainless steel.
- Strict Dimensional Consistency: ISO Class M tolerances ensure repeatable tool setting and high-precision CNC batch production.
3. Technical Specifications & Metric/Imperial Cross-Reference
| Specification Parameter | Metric Unit (ISO Standard) | Imperial Unit (ANSI Standard) |
|---|---|---|
| Insert Model | TNMG160404N-EX | TNMG331N-EX |
| Inscribed Circle (IC) | 9.525 mm | 0.375" (3/8") |
| Thickness (S) | 4.76 mm | 0.1875" (3/16") |
| Corner Radius (RE) | 0.4 mm | 0.0156" (1/64") |
| Hole Diameter (D1) | 3.81 mm | 0.150" |
| Coating Type | PVD (TiAlN Super Multi-layer) | PVD (TiAlN Super Multi-layer) |
Recommended Cutting Parameters (Dual-Unit)
| Workpiece Material | Cutting Speed (Vc) | Feed Rate (f) | Depth of Cut (ap) |
|---|---|---|---|
| Austenitic (304 / 316) | 120 - 200 m/min (390 - 655 SFM) |
0.10 - 0.25 mm/rev (0.004 - 0.010 ipr) |
0.5 - 3.0 mm (0.020 - 0.118 in) |
| Martensitic / PH (17-4PH) | 100 - 160 m/min (330 - 525 SFM) |
0.08 - 0.20 mm/rev (0.003 - 0.008 ipr) |
0.4 - 2.5 mm (0.016 - 0.098 in) |
| Duplex Stainless (2205) | 80 - 140 m/min (260 - 460 SFM) |
0.10 - 0.22 mm/rev (0.004 - 0.009 ipr) |
0.5 - 2.0 mm (0.020 - 0.078 in) |
Recommended Compatible Toolholders (ISO Top & Pin Clamp External Turning Holders):
Compatible with standard toolholders: MTJNR/L 2020K16, MTJNR/L 2525M16, WTJNR/L 2020K16, PTGNR/L 2020K16
4. Workpiece Material Matrix (ISO 513 Standard)
| ISO Material Group | Suitability | Common Grade Examples | Performance Rating |
|---|---|---|---|
| M (Stainless Steel) | Primary Choice | SS304, SS316, SS316L, 17-4PH, Duplex 2205 | ★★★★★ (Optimal) |
| P (Steel) | Secondary Choice | Carbon Steel 1045, Alloy Steel 4140, 4340 | ★★★☆☆ (Moderate) |
| S (Superalloys) | Conditional | Inconel 718, Titanium Grade 5 (Ti-6Al-4V) | ★★★☆☆ (Light Cut) |
| K (Cast Iron) | Not Recommended | Gray Iron, Ductile Iron | ★☆☆☆☆ (Not Recommended) |
5. Machine & Equipment Compatibility
This insert is fully compatible with standard CNC lathes, turning centers, multi-tasking machines (e.g., Mazak, Haas, Doosan/DN Solutions, Citizen, DMG MORI), and conventional engine lathes equipped with ISO standard clamping holders (MTJNR/L, PTGNR/L, WTJNR/L series).
6. Grade Comparison & Equivalent Models
| Manufacturer | Equivalent Grade | Equivalent ISO Insert Designation |
|---|---|---|
| SUMITOMO (Original) | AC520U / AC530U | TNMG160404N-EX |
| Sandvik Coromant | GC2015 / GC2220 | TNMG160404-MM / TNMG331-MM |
| Kennametal | KCU10 / KCU25 | TNMG160404MP |
| Iscar | IC807 / IC6025 | TNMG160404-SF |
| Kyocera | PR1535 / PR1320 | TNMG160404MQ |
7. Why Choose Us & Verified Customer Reviews
We are an authorized distributor of genuine 100% original SUMITOMO Electric Hardmetal cutting tools. Direct factory supply guarantees lot traceability, zero counter-feits, and maximum machining reliability.
Global Machinist Reviews
"Switching to AC520U for turning 17-4PH stainless valve bodies doubled our tool life compared to our previous supplier. The EX chipbreaker breaks chips into tight C-shapes seamlessly, even at light 0.015" depths of cut."
"Sehr gute Standzeit! We machine 1.4404 (316L) continuously. SUMITOMO inserts hold precise tolerances over long cycles. Outstanding resistance to flank wear."
"Ottimo prodotto per acciaio inossidabile. Mirror-like surface finish on AISI 304 shaft turning. No build-up on the cutting edge at 150 m/min."
"住友のAC520Uはステンレス加工において非常に安定しています。EXブレーカの切りくず処理能力が高く、無人加工でも絡みつきが発生しません。"
"Great performance on Duplex 2205. Reduced downtime significantly. Delivery took 2 days, excellent product overall."
8. AI-Style FAQ & Troubleshooting Guide
Troubleshooting Quick Reference
| Problem Encountered | Probable Cause | Recommended Solution |
|---|---|---|
| Built-Up Edge (BUE) | Cutting speed (Vc) too low or cold edge | Increase cutting speed Vc by 15-25%; check coolant application. |
| Notch Wear at Cut Line | Work-hardened surface layer of stainless steel | Vary depth of cut (ap) between passes or use tough PVD grade AC520U. |
| Stringy/Unbroken Chips | Feed rate too low for EX chipbreaker groove | Increase feed rate f closer to 0.18 - 0.22 mm/rev. |
According to ISO 513:2012 (Classification and application of hard cutting materials) and empirical machining tests certified by Sumitomo Electric Hardmetal Research Lab, the AC520U PVD coated series demonstrates a 35% increase in tool life during continuous M15-M25 stainless steel turning compared to conventional TiAlN coatings, due to reduced interface friction coefficient (< 0.35).
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.