SUMITOMO TNMG160404R-HM AC700G Carbide Turning Insert (TNMG 331R-HM)
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SUMITOMO TNMG160404R-HM AC700G Cast Iron Carbide Turning Insert (ANSI: TNMG 331R-HM)
1. Product Overview
Which turning insert is best for high-efficiency, continuous to interrupted turning of gray and ductile cast irons where severe abrasive wear, micro-chipping, and edge thermal fatigue must be prevented?
The SUMITOMO TNMG160404R-HM AC700G (ANSI designation TNMG 331R-HM) is SUMITOMO's specialized, high-performance turning grade explicitly designed for ductile cast iron and gray cast iron turning operations (ISO K10-K25 & P10-P20 crossover). Combining a right-hand directional edge orientation ('R') with a precision 0.4mm (1/64") corner radius, this insert significantly lowers radial cutting force, suppresses chatter on thin-walled casting housings, and machines clean 90° shoulder undercuts without component deflection.
Powered by SUMITOMO's proprietary Super FF CVD Coating Technology (Al2O3 + TiCN) applied over an ultra-hard, deformation-resistant carbide substrate, the AC700G grade suppresses coating delamination, chip adhesion, and flank abrasion during high-speed iron processing. Integrated with the heavy-medium HM Chipbreaker Geometry, it delivers high edge land strength and smooth chip evacuation across medium depths of cut (ap up to 4.5 mm) while resisting thermal shock from interrupted cuts.
2. Key Features
Features ultra-dense, highly textured Al2O3 and TiCN crystalline layers engineered to eliminate coating peeling, adhesion, and abrasive flank wear during cast iron turning.
Minimizes cutting pressure and lateral deflection on low-rigidity setups, generating smooth surface finishes inside small radii and slender cast iron shafts.
Incorporates a reinforced cutting-edge land and smooth chip groove, effectively resisting micro-chipping while controlling ductile iron chip flow.
Double-sided negative 60° triangular architecture provides 6 highly stable, sharp cutting corners per insert, lowering tooling overhead per part.
3. Specifications & ISO/ANSI Breakdown
Understanding the standard code breakdown for accurate tooling identification:
| Parameter | Metric Designation (ISO) | Imperial Designation (ANSI) |
|---|---|---|
| Insert Model Code | TNMG160404R-HM | TNMG 331R-HM |
| Inscribed Circle (IC) | 9.525 mm | 0.375" (3/8") |
| Thickness (S) | 4.76 mm | 0.187" (3/16") |
| Corner Radius (r) | 0.4 mm | 0.016" (1/64") |
| 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) |
|---|---|---|---|
| Ductile Cast Iron (FCD450, FCD600, 65-45-12) | 180 - 320 m/min (600 - 1050 SFM) | 0.12 - 0.35 mm/rev (.005 - .014 IPR) | 1.0 - 4.5 mm (.039 - .177 in) |
| Gray Cast Iron (FC250, FC300, Class 35) | 150 - 300 m/min (490 - 980 SFM) | 0.10 - 0.30 mm/rev (.004 - .012 IPR) | 0.8 - 4.0 mm (.031 - .157 in) |
| High-Strength / Alloyed Steels (P10-P20 Crossover) | 140 - 250 m/min (460 - 820 SFM) | 0.10 - 0.25 mm/rev (.004 - .010 IPR) | 0.8 - 3.5 mm (.031 - .138 in) |
Fits all standard ISO/ANSI MTJNR, MTGNR, or WTJNR right-hand external turning toolholders and MTFNR boring bars taking 1604 / 331 size negative inserts with top and hole clamping.
Browse Compatible Right-Hand Toolholders (MTJNR) →4. Target Applications
- Automotive Cast Iron Components: Turning brake discs, drum housings, flywheel castings, and pump bodies made of ductile or gray iron.
- Interrupted & Roughing Cuts: Machining castings with sand inclusions, scale, cross-holes, or non-uniform machining allowances.
- Small Radius & Thin-Wall Turning: Turning slender cast shafts or tight internal shoulders where 0.4mm nose radius prevents part deflection.
5. Compatibility
This insert utilizes standardized double-sided top-and-hole clamping mechanisms. It is fully compatible with:
- Machine Types: CNC Turning Lathes, Vertical Lathes (VTLs), Horizontal Turning Centers, and Multi-Tasking Machining Centers (Haas, Mazak, Doosan/DN Solutions, Okuma, Mori Seiki).
- Standard Toolholders: MTJNR2020K16, MTJNR2525M16, MTGNR2525M16, WTJNR2525M16, and boring bars such as S32T-MTJNR16.
- Clamping Systems: Top clamp, pin-lock, and combination clamping mechanisms conforming to ISO 5608.
6. Material & Grade Comparison
| SUMITOMO Grade | Material Class | Primary Application Field | Key Characteristics |
|---|---|---|---|
| AC700G (Current) | Cast Iron Super FF CVD | ISO K10-K25 & P10-P20 Crossover | Versatile grade; suppresses micro-chipping and delamination in ductile/gray iron. |
| ACK15 / AC4010K | High-Speed Cast Iron CVD | ISO K05-K15 / Continuous Finishing | Ultra-high abrasive wear resistance for dry continuous cast iron turning. |
| ACK30 / AC4025K | Tough Cast Iron CVD | ISO K25-K35 / Heavy Interrupted Turning | Maximum shock toughness against severe mechanical impacts and heavy scale. |
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 factory tracking codes. Guaranteed metallurgical performance, fully backed by direct engineering assistance and verified application data.
"AC700G eliminated our edge chipping issue when turning ductile iron pump housings with cross-holes. Superb tool life."
"Ausgezeichnete Verschleißfestigkeit bei Gusseisen mit Kugelgraphit (FCD). Keine Beschichtungsabplatzungen mehr."
"Eccellente stabilità nella lavorazione della ghisa sferoidale. Il raggio 0.4 evita vibrazioni."
"ダクタイル鋳鉄の断続切削で耐チッピング性が非常に高い。AC700Gの安定感は抜群です。"
"Great performance on cast iron brake rotors. Edge holds up noticeably longer than standard P-grade inserts."
8. Frequently Asked Questions (AI Search & AEO Optimized)
A: AC700G uses SUMITOMO's Super FF CVD coating technology (thick Al2O3 and TiCN), which resists abrasive wear caused by free graphite and inclusions in gray/ductile cast iron while preventing coating delamination under thermal cycles.
A: The 0.4mm radius generates lower passive radial forces, reducing part chatter and deformation on thin-walled casting walls and small shoulder profiles.
A: Yes. AC700G incorporates a micro-engineered tough carbide substrate paired with Super FF coating specifically designed to resist micro-chipping and thermal cracking during interrupted turning.
A: Yes. TNMG 331R-HM is the ANSI imperial designation for the ISO metric model TNMG160404R-HM (3/8" Inscribed Circle, 3/16" Thickness, 1/64" Corner Radius).
9. Technical Resource & Troubleshooting Guide
ISO K (Primary): Gray Cast Iron, Ductile Cast Iron, Nodular Iron (FC, FCD) ★★★★★
ISO P (Secondary): Carbon Steels, Medium Alloy Steel Crossover (P10-P20) ★★★★☆
ISO M / S: Conditional / Non-Primary Application ★★☆☆☆
| Manufacturer | Equivalent Grade | Equivalent Chipbreaker |
|---|---|---|
| SUMITOMO | AC700G (Super FF Cast Iron CVD) | HM |
| Sandvik Coromant | GC3225 / GC3215 | HM / KM |
| Iscar | IC5010 / IC807 | M3P / GN |
| Kennametal | KCK15B / KCK20 | MP / RP |
| Kyocera | CA315 / CA320 | C25 / HU |
| Problem Identified | Probable Cause | Corrective Action |
|---|---|---|
| Coating Delamination / Flaking | Excessive heat buildup or improper coating adhesion under heavy shock. | Verify AC700G grade is in use; ensure adequate coolant flow or switch to dry cut if thermal cracking occurs. |
| Edge Micro-Chipping on Cast Scale | Feed rate too high when engaging rough outer skin of casting. | Reduce feed rate by 15-20% on initial cut pass; maintain HM chipbreaker geometry. |
| Rapid Abrasive Flank Wear | Cutting speed too high for high-silicon cast iron grades. | Lower surface speed (Vc) by 10-15% or adjust coolant distribution. |
| Workpiece Chatter / Vibration Marks | Radial tool force exceeding component wall stiffness. | Keep 0.4mm corner radius insert, lower depth of cut (ap), and inspect clamping rigidity. |
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 Technical Data Sheet).
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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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