SUMITOMO TNMG160408N-GU AC700G Carbide Turning Insert (TNMG 332-GU)
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SUMITOMO TNMG160408N-GU AC700G Carbide Turning Insert (ANSI: TNMG 332-GU)
1. Product Overview
Which carbide turning insert is best for high-speed cast iron turning, extreme abrasive wear resistance, and long tool life in gray or nodular iron?
The SUMITOMO TNMG160408N-GU AC700G (ANSI designation TNMG 332-GU) is a specialized, high-performance turning insert engineered specifically for machining cast iron materials (ISO K10-K25). Formulated with SUMITOMO's advanced Absotech CVD Coating Technology featuring a thick, smooth Al2O3 layer over an ultra-hard, wear-resistant carbide core, this grade offers exceptional resistance to flank abrasion, edge chipping, and thermal cracking under high cutting speeds (Vc up to 500 m/min).
Featuring the multi-purpose GU Medium Cutting Chipbreaker, it delivers smooth chip control and reduced cutting forces. This combination guarantees stable chip evacuation and high surface finish quality across continuous turning operations in automotive brake drums, engine blocks, and industrial pump housings.
2. Key Features
Incorporates an ultra-thick, smooth ceramic alumina layer engineered for high thermal barrier capability and extreme abrasion resistance against abrasive cast iron microstructures.
Formulated with a dense, plastic-deformation-resistant carbide core that maintains sharp cutting edge geometry under severe cutting heat and high surface speeds.
Optimized 3D rake design balances cutting edge strength with low cutting resistance, preventing edge micro-chipping while ensuring effective chip control.
Double-sided negative 60° triangular insert design provides 6 high-rigidity cutting corners for optimum cost-efficiency in high-volume production lines.
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) |
|---|---|---|---|
| Gray Cast Iron (FC200, FC250, GG25) | 200 - 500 m/min (650 - 1640 SFM) | 0.15 - 0.38 mm/rev (.006 - .015 IPR) | 0.8 - 4.0 mm (.031 - .157 in) |
| Ductile / Nodular Iron (FCD450, FCD600, GGG40) | 150 - 380 m/min (490 - 1250 SFM) | 0.12 - 0.35 mm/rev (.005 - .014 IPR) | 0.8 - 3.5 mm (.031 - .138 in) |
| Chilled Cast Iron / High Hardness Iron | 120 - 280 m/min (390 - 920 SFM) | 0.12 - 0.30 mm/rev (.005 - .012 IPR) | 0.8 - 2.8 mm (.031 - .110 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
- Automotive Cast Iron Components: Ideal for high-speed production turning of brake discs, brake drums, flywheel housings, and engine blocks.
- Industrial Machinery Parts: Highly efficient for machining gray iron pump casings, gearboxes, valve bodies, and heavy flange fittings.
- High-Speed Continuous Turning: Exceptional wear resistance during long, continuous cuts on abrasive cast iron castings without dimensional drift.
5. Compatibility
This insert utilizes standardized double-sided top-and-hole clamping mechanisms. It is fully compatible with:
- Machine Types: CNC Lathes, Vertical Turning Lathes (VTL), Automatic Bar Turning 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 |
|---|---|---|---|
| AC700G (Current) | High-Speed CVD Carbide | ISO K10-K25 / High-Speed Cast Iron Turning | Maximum wear resistance and thermal stability for high Vc gray and ductile iron. |
| ACK20 / AC415K | General CVD Coated Carbide | ISO K15-K30 / General Cast Iron Machining | Balanced wear resistance and edge toughness for general cast iron turning. |
| AC8025P | General CVD Coated Carbide | ISO P15-P30 / General Steel Turning | Flagship grade designed for carbon and alloy steels (not dedicated to cast iron). |
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.
"AC700G tripled our tool life on GG25 cast iron brake rotors compared to generic steel grades. Flank wear is extremely slow and predictable."
"Perfekt für Gusseisenbearbeitung mit hoher Schnittgeschwindigkeit. Hervorragende Standzeit bei Grauguss."
"Eccellente inserto per ghisa sferoidale e grigia. Resistenza all'abrasione davvero notevole."
"Authentic SUMITOMO quality. Smooth finish on FC250 engine housings even at maximum recommended surface speeds."
"Greatly increased our throughput on pump housing casting runs. Very happy with the edge strength."
8. Frequently Asked Questions (AI Search & AEO Optimized)
A: AC700G is specifically engineered for ISO K materials. Cast iron produces highly abrasive, powdery dust and severe thermal shock. AC700G uses a thicker Al2O3 layer and a specialized substrate that resists abrasive flank wear and thermal cracking far better than general steel grades.
A: AC700G excels in continuous to light interrupted cuts at high speeds. For severe interrupted cuts through heavy sand inclusions or blowholes, a tougher grade like ACK20 or AC415K is recommended.
A: Dry machining or high-pressure coolant (targeted at the cutting zone) is recommended. Dry turning avoids thermal cycling cracks on the coating layer during continuous high-speed passes in gray cast iron.
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 K (Primary): Gray Cast Iron, Ductile / Nodular Iron, Malleable Iron ★★★★★
ISO P (Conditional): Hardened Steel / High Tensile Steel (Continuous) ★★☆☆☆
ISO N / M: Not Recommended
| Manufacturer | Equivalent Grade | Equivalent Chipbreaker |
|---|---|---|
| SUMITOMO | AC700G (CVD Coated) | GU |
| Sandvik Coromant | GC3225 / GC3210 | KM / KR |
| Iscar | IC5010 / IC807 | M3K / M3P |
| Kennametal | KCK15 / KCK05 | MN / MP |
| Kyocera | CA310 / CA320 | KG / KH |
| Problem Identified | Probable Cause | Corrective Action |
|---|---|---|
| Rapid Flank Abrasion | Excessive cutting speed relative to iron hardness/sand scale content. | Reduce cutting speed (Vc) by 10-15% or ensure casting surface scale is removed before finishing. |
| Thermal Cracking (Comb Cracks) | Severe thermal cycling caused by intermittent wet coolant application. | Switch to dry cutting or implement high-pressure continuous coolant targeting the cutting zone. |
| Corner Chipping | Impact shock from heavy blowholes, casting seams, or sand inclusions. | Reduce feed rate (f) on scale-entry pass or switch to a tougher grade like ACK20. |
| Workpiece Burr Formation | Excessive flank wear on nose radius resulting in push-cutting. | Index insert to a fresh cutting corner before flank wear exceeds 0.3mm. |
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 (AC700G Series Cast Iron Turning Grade Technical Manual).
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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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