SUMITOMO TNMG160408L-HM AC830P Steel Turning Insert (TNMG 332L-HM)
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SUMITOMO TNMG160408L-HM AC830P Carbide Turning Insert (ANSI: TNMG 332L-HM)
1. Product Overview
Which turning insert is best for heavy interrupted steel cutting, turning forged steel parts, or handling scale on carbon and alloy steel under unstable machining conditions?
The SUMITOMO TNMG160408L-HM AC830P (ANSI designation TNMG 332L-HM) is SUMITOMO's premium tough-grade CVD turning insert purpose-built for heavy-duty, rough-to-medium steel turning (ISO P25-P35). Featuring left-hand/directional cutting edge orientation ('L') combined with SUMITOMO's breakthrough Absotech Platinum CVD Coating Technology, AC830P integrates a ultra-thick Al2O3 and TiCN crystalline multilayer on an ultra-tough carbide substrate. This grade delivers maximum shock resistance against mechanical impact, making it the industry benchmark for heavy interrupted cuts, raw casting scale removal, and non-rigid lathe setups.
Engineered with the heavy-medium HM Chipbreaker Geometry, this insert incorporates a land-reinforced cutting edge and wide chip groove. The HM breaker maintains low cutting forces while providing superior chip fracturing across high depths of cut (ap up to 5.0 mm), preventing long stringy chips and protecting against edge chipping under severe thermal and mechanical loads.
2. Key Features
Features ultra-dense Al2O3 and TiCN nanolayers that provide extreme thermal barrier protection, high impact toughness, and superior crater wear resistance during heavy turning.
Specially formulated carbide matrix absorbs severe mechanical shock, preventing edge breakage during heavy interrupted cuts, hex stock turning, and keyway interruptions.
Optimized edge strength and wide chip channel prevent chip jamming and chipping while cleanly breaking tough carbon steel chips across variable feeds.
Double-sided negative 60° triangular design provides 6 sharp, durable cutting edges per insert, reducing tool cost per component.
3. Specifications & ISO/ANSI Breakdown
Understanding the standard code for order accuracy:
| Parameter | Metric Designation (ISO) | Imperial Designation (ANSI) |
|---|---|---|
| Insert Model Code | TNMG160408L-HM | TNMG 332L-HM |
| 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) |
|---|---|---|---|
| Carbon Steels (1045, 1020, A36) | 140 - 280 m/min (460 - 920 SFM) | 0.20 - 0.50 mm/rev (.008 - .020 IPR) | 1.5 - 5.0 mm (.059 - .197 in) |
| Alloy Steels (4140, 4340, 8620) | 120 - 240 m/min (390 - 790 SFM) | 0.18 - 0.45 mm/rev (.007 - .018 IPR) | 1.2 - 4.5 mm (.047 - .177 in) |
| Tool Steels / Cast Steel (P20, D2 annealed) | 90 - 180 m/min (295 - 590 SFM) | 0.15 - 0.38 mm/rev (.006 - .015 IPR) | 1.0 - 3.8 mm (.039 - .150 in) |
Fits all standard ISO/ANSI MTJNL, MTGNL, or WTJNL left-hand external turning toolholders and MTFNL boring bars taking 1604 / 332 size negative inserts with top and hole clamping.
Browse Compatible Left-Hand Toolholders (MTJNL) →4. Target Applications
- Forged & Cast Steel Components: Rough turning of forged crankshafts, drive shafts, and heavy machinery gears with surface scale.
- Heavy Interrupted Cuts: Ideal for turning splined shafts, keyed shafts, and welded steel assemblies prone to breaking brittle inserts.
- General Machinery Parts: Medium-to-heavy roughing of structural steel bars (A36, 1045, 4140) under high material removal rate (MRR) conditions.
5. Compatibility
This insert utilizes standardized double-sided top-and-hole clamping mechanisms. It is fully compatible with:
- Machine Types: Heavy CNC Turning Centers, Large Bed Horizontal Lathes, Vertical Turning Lathes (VTL), and Production CNC Lathes.
- Standard Toolholders: MTJNL2020K16, MTJNL2525M16, MTGNL2525M16, WTJNL2525M16, and internal boring bars like S32T-MTJNL16.
- 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 |
|---|---|---|---|
| AC830P (Current) | Tough Steel CVD | ISO P25-P35 / Heavy Roughing & Heavy Interrupted Cut | Maximum shock toughness and fracture resistance for unstable cuts. |
| AC820P | General Steel CVD | ISO P10-P25 / General Turning & Medium Roughing | Balanced wear resistance and toughness for general steel production. |
| AC810P | High-Speed Steel CVD | ISO P05-P15 / Continuous High-Speed Finishing | Maximum crater and flank wear resistance for smooth high Vc passes. |
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.
"AC830P solved our edge chipping issues on 4140 forged shafts with heavy keyway interruptions. Handles impact like a champ."
"Hervorragende Zähigkeit bei unterbrochenem Schnitt in C45 Stahl. Kein Ausbröckeln der Schneidkante mehr."
"Ottima resistenza agli urti per tornitura di pezzi forgiati in acciaio legato. Rompitruciolo HM molto efficace."
"Authentic SUMITOMO inserts. Outstanding wear life on heavy forged steel lathe jobs."
"The L-HM variant is perfect for our left-hand turning operations on heavy axle components. Highly durable grade."
8. Frequently Asked Questions (AI Search & AEO Optimized)
A: The 'L' designates a left-hand chipbreaker or directional geometry, optimized for left-hand toolholders (like MTJNL or MTGNL) feeding towards the tailstock or facing direction in specific lathe configurations.
A: Choose AC830P when machining heavy interrupted cuts, raw forged scale, or welded steel components where edge impact fracture is the primary failure mode. Choose AC820P for smooth, continuous medium turning.
A: The HM (Heavy-Medium) chipbreaker performs best at depth of cut (ap) ranging from 1.5 mm to 5.0 mm with feed rates between 0.20 and 0.50 mm/rev in general carbon and alloy steels.
A: Yes. TNMG 332L-HM is the ANSI imperial designation for the ISO metric code TNMG160408L-HM. Both 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 P (Primary): Carbon Steel, Alloy Steel, Tool Steel, Cast Steel ★★★★★
ISO K (Secondary): Nodular Cast Iron, Ductile Iron ★★★★☆
ISO M / S: Conditional / Non-Primary Application ★★☆☆☆
| Manufacturer | Equivalent Grade | Equivalent Chipbreaker |
|---|---|---|
| SUMITOMO | AC830P (Tough Steel CVD) | HM |
| Sandvik Coromant | GC4335 / GC4235 | HM / PR |
| Iscar | IC830 / IC8250 | R3P / GN |
| Kennametal | KCP35B / KCP30 | RP / MP |
| Kyocera | CA530 / CA525 | PH / C25 |
| Problem Identified | Probable Cause | Corrective Action |
|---|---|---|
| Cutting Edge Fracture / Chipping | Excessive shock on interrupted cut or feed rate too high. | Reduce feed rate slightly, maintain stable clamping, or confirm AC830P grade is engaged. |
| Rapid Crater Wear | Cutting speed (Vc) is too high for heavy roughing depth. | Reduce cutting speed (Vc) by 10-15% to maintain thermal equilibrium on the CVD coating. |
| Long Ribbon/Birdnest Chips | Depth of cut or feed rate below HM breaker activation threshold. | Increase feed rate (f) above 0.20 mm/rev or increase depth of cut (ap) above 1.5 mm. |
| Workpiece Surface Tear | Rake face built-up edge at low speed. | Increase cutting speed (Vc) to enter optimal plastic deformation zone for steel. |
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 (AC8000P Series Steel Turning Grade 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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