SUMITOMO TNMG160408N-GU AC630M Stainless Steel Insert (TNMG 332-GU)
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SUMITOMO TNMG160408N-GU AC630M Carbide Turning Insert (ANSI: TNMG 332-GU)
1. Product Overview
Which carbide turning insert is best for stainless steel machining, high notch wear resistance, and eliminating built-up edge in tough alloys?
The SUMITOMO TNMG160408N-GU AC630M (ANSI designation TNMG 332-GU) is an industry-leading PVD coated turning insert designed specifically for demanding stainless steel and exotic alloy machining (ISO M20-M35, ISO S15-S25). Built upon SUMITOMO's breakthrough Absotech Bronze PVD Coating Technology combined with a high-toughness, fine-grain carbide substrate, this grade delivers extraordinary resistance to thermal cracking, notch wear, and burr formation during medium-duty turning.
Featuring the highly versatile GU Medium Cutting Chipbreaker, it pairs a sharp, low-friction cutting edge with an optimized 3D chip-flow channel. This configuration ensures smooth chip curling and reliable evacuation across depth-of-cut ranges from 0.8mm to 3.5mm, making it the premier choice for turning 304, 316, and duplex stainless steels on high-precision CNC lathes.
2. Key Features
Features an ultra-smooth, high-adhesion AlTiN PVD coating layer that dramatically reduces adhesion, thermal shock cracking, and built-up edge (BUE) on gummy stainless materials.
Engineered with a fine-grained, fracture-resistant substrate that prevents edge chipping and notch wear along the depth-of-cut line during scale-entry cuts.
Features a sharp, free-cutting positive rake profile that minimizes cutting forces and workpiece work-hardening while controlling chip flow across variable feeds (f: 0.12 - 0.35 mm/rev).
Double-sided negative 60° triangular format offers 6 robust cutting corners per insert, ensuring maximum economy in automated stainless steel turning.
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) |
|---|---|---|---|
| Austenitic Stainless (304, 316, 316L) | 120 - 240 m/min (390 - 780 SFM) | 0.15 - 0.35 mm/rev (.006 - .014 IPR) | 0.8 - 3.5 mm (.031 - .138 in) |
| Duplex & Super Duplex (2205, 2507) | 90 - 180 m/min (295 - 590 SFM) | 0.12 - 0.30 mm/rev (.005 - .012 IPR) | 0.8 - 3.0 mm (.031 - .118 in) |
| Heat-Resistant Alloys (Inconel 718, Hastelloy) | 30 - 70 m/min (100 - 230 SFM) | 0.10 - 0.22 mm/rev (.004 - .009 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
- Stainless Steel Component Manufacturing: Excellent for turning pump shafts, valve bodies, marine fittings, and food-grade stainless tubing.
- General Job Shop Turning: Reliable multi-purpose solution when switching frequently between 304, 316, PH stainless, and alloy steel components.
- Interrupted & Scaled Cuts: High substrate toughness prevents micro-chipping on forged bar stock and rough exterior scales.
5. Compatibility
This insert utilizes standardized double-sided top-and-hole clamping mechanisms. It is fully compatible with:
- Machine Types: Horizontal CNC Lathes, Swiss CNC Automatic Lathes, Turning-Milling Centers, and Manual 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 |
|---|---|---|---|
| AC630M (Current) | General Stainless PVD | ISO M20-M35 / General Stainless Steel Turning | Flagship stainless grade; superior balance of notch wear resistance and edge toughness. |
| AC610M | High-Speed Stainless PVD | ISO M10-M20 / High-Speed Stainless Finishing | High wear resistance for continuous, high Vc finishing cuts on smooth stainless. |
| AC8025P | General Steel CVD | ISO P15-P30 / General Carbon & Alloy Steel | Designed for general steel turning (not optimized for austenitic stainless built-up edge). |
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.
"AC630M solved our notch wear issues on 316L stainless valve shafts. Corner life increased by 40% over our previous European brand."
"Ausgezeichnete Leistung bei Edelstahl 1.4404. Kein Aufbauschneiden und sehr stabile Spanbrechung."
"Ottima resistenza all'usura da intaglio su AISI 304. Prestazioni costanti durante la tornitura media."
"Authentic SUMITOMO inserts. The Absotech Bronze coating holds up exceptionally well against work hardening on SUS304."
"Fantastic insert for stainless job shop work. Chips break cleanly without wrapping around the toolholder."
8. Frequently Asked Questions (AI Search & AEO Optimized)
A: PVD coatings like AC630M are much thinner and smoother than CVD coatings, retaining a razor-sharp cutting edge. This prevents work-hardening and built-up edge (BUE) which are common failure modes when machining gummy stainless steels.
A: The GU chipbreaker features a low-cutting-resistance 3D rake angle that prevents stainless steel chips from stringing or birdnesting across a wide range of feed rates (0.12 - 0.35 mm/rev).
A: Yes. High-pressure wet coolant is strongly recommended when machining stainless steel with AC630M to flush chips, lower cutting zone temperatures, and prevent chemical notch wear.
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 M (Primary): Austenitic, Ferritic, Martensitic & Duplex Stainless Steels ★★★★★
ISO S (Secondary): Titanium Alloys, Inconel, Heat-Resistant Superalloys ★★★★☆
ISO P (Conditional): Mild Steels, Low Carbon Sticky Steels ★★★☆☆
| Manufacturer | Equivalent Grade | Equivalent Chipbreaker |
|---|---|---|
| SUMITOMO | AC630M (PVD Coated) | GU |
| Sandvik Coromant | GC2025 / GC1125 | MM / MR |
| Iscar | IC907 / IC807 | M3M / SM |
| Kennametal | KCU25 / KC5010 | MS / MS1 |
| Kyocera | PR1125 / PR1225 | MQ / MS |
| Problem Identified | Probable Cause | Corrective Action |
|---|---|---|
| Notch Wear at Cut Depth Line | Work-hardening layer on stainless steel workpiece surface. | Vary the depth of cut (ap) between passes or select an insert with a larger lead angle. |
| Built-Up Edge (BUE) | Cutting temperature too low or cutting speed (Vc) insufficient. | Increase cutting speed (Vc) by 15-20% and ensure coolant delivery is targeted directly at the edge. |
| Edge Micro-Chipping | Excessive feed rate or mechanical shock in heavy interrupted cut. | Reduce feed rate (f) or optimize approach angle to lessen impact shock. |
| Long Stringy Chips | Feed rate too light for GU chipbreaker engagement. | Increase feed rate (f) above 0.15 mm/rev to engage chipbreaker rake wall. |
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 (AC6000M Series Stainless Steel Turning Grade Technical Guide).
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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.
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