SUMITOMO TCMT16T304N-SU AC630M CVD Carbide Insert | TCMT32.51N-SU
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1. Product Overview
Which positive turning insert is best suited for fine-to-medium turning and chatter-sensitive internal boring on austenitic stainless steel, heat-resistant alloys, and steel forgings?
The SUMITOMO TCMT16T304N-SU AC630M (ANSI designation: TCMT32.51N-SU AC630M) is a high-precision 60° triangular single-sided indexable turning insert engineered with a 7° positive clearance angle to lower cutting forces and eliminate chatter. Powered by SUMITOMO's AC630M Absotech CVD Coating Grade—featuring an ultra-tough TiCN/Al2O3 multi-layer composite coating over an engineered tough carbide substrate—this insert resists thermal cracking, notch wear, and edge chipping under light-to-medium interrupted cutting across ISO M15–M35, P15–P35, and S15–S30 ranges.
Equipped with a precise 0.4 mm (1/64") corner radius, Neutral (N) edge prep, and the versatile SU Medium-Cut Chipbreaker, this insert guarantees active chip breaking and controlled heat dissipation across fine-to-medium cut depths (ap: 0.5–2.5 mm) and light feed rates (f: 0.08–0.22 mm/rev). The positive geometry makes it an exceptional performer for low-rigidity setups, long-overhang internal boring bars, and small-diameter external turning shanks on CNC lathes.
ISO / ANSI Designation Breakdown
2. Key Features
- Absotech CVD AC630M Grade Technology: Thermally insulated composite coating suppresses oxidation and adhesion, delivering up to 1.8x longer tool life in stainless steel turning.
- Low-Force 7° Positive Relief Edge: Reduces tooling deflection, enabling chatter-free performance on long-reach boring bars and thin-walled parts.
- 0.4 mm Fine Nose Radius: Delivers exceptional Ra surface finish and tight dimensional tolerances during profiling pass operations.
- SU Multi-Stage Chipbreaker: Optimizes chip curling to prevent long ribbon chips from wrapping around tools or damaging part surfaces.
- High Thermal Shock Barrier: Withstands intermittent coolant spraying and heat spikes without premature edge fracturing.
3. Specifications & Dual-Unit Comparison
| Specification Parameter | Metric Unit (ISO Standard) | Imperial Unit (ANSI Standard) |
|---|---|---|
| Insert Designation | TCMT16T304N-SU | TCMT32.51N-SU |
| Inscribed Circle (IC) | 9.525 mm | 0.375" (3/8") |
| Thickness (S) | 3.97 mm | 0.156" (5/32") |
| Corner Radius (RE) | 0.4 mm | 0.0156" (1/64") |
| Hole Diameter (D1) | 4.40 mm | 0.173" |
| Substrate Grade | Absotech CVD Coated (AC630M) | Absotech CVD Coated (AC630M) |
Recommended Cutting Parameters
| Workpiece Material | Cutting Speed (Vc) | Feed Rate (f) | Depth of Cut (ap) |
|---|---|---|---|
| Stainless Steel (304, 316, 316L, 17-4PH) | 130 - 230 m/min (425 - 750 SFM) |
0.08 - 0.22 mm/rev (0.003 - 0.009 ipr) |
0.5 - 2.5 mm (0.020 - 0.098 in) |
| Alloy Steel (4140, 4340, 8620) | 150 - 270 m/min (490 - 880 SFM) |
0.10 - 0.25 mm/rev (0.004 - 0.010 ipr) |
0.5 - 2.5 mm (0.020 - 0.098 in) |
| Heat Resistant Alloys (Inconel 718, Titanium) | 45 - 90 m/min (145 - 295 SFM) |
0.06 - 0.18 mm/rev (0.002 - 0.007 ipr) |
0.4 - 1.8 mm (0.015 - 0.070 in) |
Recommended Compatible Toolholders (ISO Screw Clamp Turning & Boring Holders):
Compatible with standard external holders: STGCR/L 2020K16, STFCR/L 2020K16, Internal Boring Bars: A16M-STFCR16, S20R-STFCR16
Workpiece Material Matrix (ISO 513 Standard)
| ISO Material Group | Suitability | Common Grade Examples | Performance Rating |
|---|---|---|---|
| M (Stainless Steel) | Primary Choice | 304, 316, 316L, 17-4PH, 2205 Duplex | ★★★★★ (Optimal) |
| P (Steel Alloys) | Primary Choice | Carbon Steel 1045, Alloy Steel 4140, 4340 | ★★★★★ (Optimal) |
| S (Exotic Alloys) | Secondary Choice | Inconel 718, Hastelloy C276, Titanium Alloys | ★★★☆☆ (Good) |
| K (Cast Iron) | Conditional | Ductile Iron, Nodular Iron | ★★☆☆☆ (Limited) |
4. Applications
- Small-Bore Internal Profiling: Precision ID boring on stainless valve bodies using 16mm shank boring bars where cutting pressure must be minimized.
- Fine-to-Medium External Turn-Facing: High-precision outer diameter turning and step profiling on stainless steel and alloy shafts.
- Interrupted Light Cutting: Turning stainless forgings and cast stock with small surface keyways or cross-drilled holes.
5. Compatibility
Fits all standard ISO positive screw-clamp external shanks (STGCR/L, STFCR/L) and internal boring bars (A/S-STFCR/L). Fully compatible with standard CNC turning centers and lathes from Haas, Mazak, Okuma, Doosan/DN Solutions, Citizen, and Hardinge.
6. Grade Comparison & Equivalent Models
| Manufacturer | Equivalent Grade | Equivalent ISO Insert Designation |
|---|---|---|
| SUMITOMO (Original) | AC630M (Tough CVD) / AC6020M | TCMT16T304N-SU |
| Sandvik Coromant | GC2025 / GC1115 | TCMT16T304-MF / TCMT32.51-MF |
| Kyocera | CA6525 / PR1535 | TCMT16T304HQ / TCMT32.51HQ |
| Tungaloy | AH630 / T6130 | TCMT16T304-PSS |
| Iscar | IC907 / IC807 | TCMT 16T304-SM |
7. Why Choose Us
We source 100% genuine SUMITOMO Electric Hardmetal indexable cutting inserts directly through verified industrial supply channels. Every factory box undergoes strict lot inspection to guarantee uniform edge sharpness, PVD/CVD layer integrity, and tight tolerance consistency for continuous CNC operation.
Verified Customer Reviews
The TCMT16T304N-SU AC630M is my top recommendation for long-reach boring bars in 316 stainless. The 0.4mm corner radius coupled with the 7-degree relief completely eliminates chatter.
Perfekt für die Innenbearbeitung von Edelstahlgehäusen. Die AC630M Sorte zeigt hervorragende Wendeplatten-Standzeiten ohne Ausbrüche.
Eccellente placchetta per tornitura fine e media su inox 304. La spoglia positiva di 7 gradi riduce lo sforzo e la rugosità superficiale è fantastica.
SUS316の小径内径加工で使用。切りくずの排出がスムーズで、AC630Mの耐熱性と耐久性は信頼できます。
Using these on our Doosan lathe for small alloy shaft jobs. Good chip control at light feeds and very consistent tool life.
8. AI-Style FAQ & Troubleshooting
Troubleshooting Quick Reference
| Problem Encountered | Probable Cause | Recommended Solution |
|---|---|---|
| Vibration / Chatter During Boring | Excessive cutting force or bar overhang ratio is too high | Ensure tool center height is exact, check clamp rigidity, or lower depth of cut ap slightly. |
| Built-Up Edge (BUE) on Tip | Cutting speed Vc is too low, causing stainless steel chip welding | Increase cutting speed Vc by 15-20% to elevate zone temperature and activate the AC630M anti-wear coating. |
| Notch Wear at Depth of Cut Line | Work hardening of stainless steel at previous pass boundary | Vary depth of cut ap between passes or use a variable DOC strategy to shift the wear line. |
Under ISO 513:2012 classification standards, SUMITOMO AC630M Absotech CVD coated grade provides exceptional thermal barrier protection and notch wear resistance across ISO M15–M35 stainless steel and ISO P15–P35 alloy turning operations.
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.