Tungaloy WNMG080404-SS MPJ350 Carbide Insert – PVD Coated for Stainless Steel Finishing
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Tungaloy WNMG080404-SS MPJ350 Carbide Turning Insert – PVD Coated Stainless Steel Finishing Specialist
Purpose-engineered for precision finishing of austenitic, duplex, and martensitic stainless steel. The MPJ350 grade with SS chipbreaker delivers ultra-low cutting forces, zero built-up edge, and exceptional surface finish on the most challenging stainless steel workpieces.
Product Overview
"Which carbide insert gives the best surface finish on stainless steel without built-up edge or work hardening?"
The Tungaloy WNMG080404-SS MPJ350 is a dedicated stainless steel finishing insert combining two purpose-designed technologies: the MPJ350 grade and the SS chipbreaker geometry. Unlike general-purpose grades that compromise between steel and stainless performance, this insert is engineered exclusively for the unique challenges of stainless steel machining — high work hardening tendency, low thermal conductivity, and strong adhesion to cutting tool surfaces.
The MPJ350 grade features a next-generation PVD TiAlN+Si (TiAlSiN) nano-composite coating over a specially formulated fine-grain carbide substrate with optimized cobalt binder content for stainless steel. The nano-Si addition creates an amorphous Si₂N₃ phase at grain boundaries that dramatically improves oxidation resistance, reduces coating friction, and prevents the adhesion of stainless steel chips to the rake face — the primary cause of built-up edge (BUE) in stainless steel turning.
The SS (Stainless Steel) chipbreaker features an extremely sharp positive rake angle, polished rake face, and narrow chip groove optimized for the low-to-medium feed rates (fn 0.05–0.18 mm/rev) typical of stainless steel finishing. This geometry minimizes cutting forces by up to 30% compared to standard geometries, reducing work hardening depth and enabling Ra ≤ 0.8 µm surface finish on 304, 316L, 2205 duplex, and 17-4PH stainless steel.
Search Keywords:
Model Code Decoder – WNMG080404-SS MPJ350
Every character in the ISO insert designation carries precise engineering meaning:
80° Trigon (W)
0° (Negative)
±0.05–0.13mm
Hole + Chip Groove (Double-sided)
8.0mm (IC 9.525mm)
4.76mm
0.4mm (R0.4)
Stainless Steel Geometry
Tungaloy MPJ Series
PVD TiAlSiN Nano
M-Grade Stainless Specialist
SS Chipbreaker & MPJ350 Grade – Stainless Steel Engineering
- SS chipbreaker – Sharp positive rake: Extreme positive rake angle reduces cutting forces by up to 30% vs. standard geometries — minimizes work hardening depth in austenitic stainless steel, preserving surface integrity and dimensional accuracy.
- SS chipbreaker – Polished rake face: Mirror-polished rake surface prevents stainless steel adhesion and built-up edge (BUE) formation — the #1 cause of surface finish degradation and premature tool failure in stainless turning.
- SS chipbreaker – Narrow chip groove: Optimized for fn 0.05–0.18 mm/rev, producing short, curled chips that evacuate cleanly without re-cutting — critical for stainless steel where chip re-cutting causes surface scratching.
- MPJ350 – TiAlSiN nano-composite coating: The nano-Si addition creates an amorphous Si₂N₃ phase at grain boundaries, reducing coating friction coefficient to <0.4 and preventing stainless steel adhesion at the chip-tool interface.
- MPJ350 – Optimized cobalt binder: Fine-grain substrate with controlled Co content provides the ideal balance of toughness and hardness for stainless steel — resists the abrasive wear from work-hardened stainless chips without micro-chipping.
Key Features
Technical Specifications
Metric & Imperial Dimensions
| Parameter | Metric | Imperial |
|---|---|---|
| Insert Shape | 80° Trigon (W) | 80° Trigon (W) |
| Inscribed Circle (IC) | 9.525 mm | 3/8 in |
| Cutting Edge Length (L) | 8.0 mm | 0.315 in |
| Insert Thickness (S) | 4.76 mm | 0.1875 in |
| Corner Radius (rε) | 0.4 mm | 1/64 in |
| Clearance Angle | 0° (Negative) | 0° (Negative) |
| Tolerance Class | M (±0.05–0.13 mm) | M (±0.002–0.005 in) |
| Hole Diameter | 3.81 mm | 0.150 in |
| Grade | MPJ350 | MPJ350 |
| Coating | PVD TiAlSiN Nano-Composite | PVD TiAlSiN Nano-Composite |
| ISO Application | M05–M25, S05–S15 | M05–M25, S05–S15 |
| Chipbreaker | SS (Stainless Steel Finishing) | SS (Stainless Steel Finishing) |
| Usable Cutting Edges | 4 edges (double-sided) | 4 edges (double-sided) |
| Packaging | 10 pcs / box | 10 pcs / box |
Recommended Cutting Parameters – Stainless Steel
| Workpiece Material | Vc (m/min) | Vc (SFM) | fn (mm/rev) | fn (in/rev) | ap (mm) |
|---|---|---|---|---|---|
| Austenitic SS 304/304L | 120–220 | 394–722 | 0.05–0.15 | 0.002–0.006 | 0.2–1.0 |
| Austenitic SS 316/316L | 100–200 | 328–656 | 0.05–0.15 | 0.002–0.006 | 0.2–1.0 |
| Duplex SS 2205/2507 | 80–160 | 262–525 | 0.05–0.12 | 0.002–0.005 | 0.2–0.8 |
| Martensitic SS 17-4PH | 100–180 | 328–591 | 0.05–0.15 | 0.002–0.006 | 0.2–1.0 |
| Super Austenitic 904L | 60–120 | 197–394 | 0.04–0.10 | 0.002–0.004 | 0.2–0.6 |
* Always use flood coolant or high-pressure coolant (HPC) for stainless steel. Never run dry — heat buildup accelerates BUE and work hardening. Start at the lower end of the speed range and increase gradually.
SS vs. TSF Chipbreaker Comparison for Stainless Steel
| Parameter | TSF (General Finishing) | SS (Stainless Specialist) ✓ |
|---|---|---|
| Rake Angle | Positive | Extreme Positive |
| Rake Face Finish | Standard ground | Mirror polished |
| BUE Resistance | Good | Excellent |
| Work Hardening Prevention | Moderate | Superior |
| Cutting Force Reduction | ~15% vs. negative | ~30% vs. negative |
| Best Material | Steel, alloy steel | Stainless steel, superalloys |
| Recommended Grade | T9115 | MPJ350 ✓ |
🔧 Compatible Tool Holders (WNMG080404)
WNMG080404-SS MPJ350 uses standard MWLNR/L 08-pocket tool holders. For stainless steel finishing, use the most rigid setup possible to minimize vibration:
For stainless steel: use the shortest possible tool overhang, tightest clamping, and highest-rigidity setup to minimize vibration and chatter.
Applications
Tungaloy Grade Comparison – Stainless Steel Turning
| Grade | Coating | ISO Range | Best For | BUE Resistance |
|---|---|---|---|---|
| MPJ350 ✓ | PVD TiAlSiN | M05–M25 | Stainless finishing, anti-BUE specialist | ★★★★★ |
| T9115 | PVD TiAlN | M10–M25 | General stainless finishing | ★★★☆☆ |
| T9125 | PVD TiAlN | M20–M30 | Stainless semi-finishing, interrupted | ★★☆☆☆ |
| AH725 | CVD | M15–M30 | Stainless semi-finishing to roughing | ★★☆☆☆ |
| MPJ300 | PVD TiAlSiN | M05–M20 | High-speed stainless finishing | ★★★★☆ |
| MPJ400 | PVD TiAlSiN | M15–M30 | Stainless semi-finishing, tougher | ★★★☆☆ |
✓ = Current product. MPJ350 is the optimal balance of BUE resistance, wear resistance, and toughness for stainless steel finishing in the Tungaloy MPJ series.
Why Choose Us
Customer Reviews
"Using WNMG080404-SS MPJ350 for finishing 316L stainless steel medical components. Zero BUE issues — surface finish is consistently Ra 0.6 across the whole batch. This insert solved the BUE problem that was ruining our surface finish with other grades."
"Perfekt für die Feinbearbeitung von 1.4404 (316L) Edelstahl. Die SS-Geometrie verhindert Aufbauschneidenbildung vollständig. Oberflächenqualität Ra 0.8 problemlos erreichbar. MPJ350 ist unser Standardwerkzeug für Edelstahlfinishing."
"Utilizzo MPJ350 per la finitura di componenti in acciaio inox 2205 duplex per applicazioni oil & gas. La geometria SS elimina il tagliente di riporto e la qualità superficiale è eccellente. Vita utensile molto consistente anche su duplex."
"SUS316Lの精密仕上げ加工にMPJ350を使用。構築刃が全く発生せず、Ra0.6を安定して実現。他もの版に比べ切削抗力が明らかに低く、薄肉部品の加工に最適です。"
"Good performance on 17-4PH stainless steel aerospace components. The SS chipbreaker handles the low feeds well and BUE is completely eliminated. Slightly prefer higher coolant pressure for best results, but overall an excellent stainless finishing insert."
"用于316L不锈钉医疗器械件精加工，SS槽型切削力小，完全没有积屑刀尖问题。Ra0.6轻松达到，工具寿命稳定。MPJ350是我们不锈钉精加工的首选。"
"Excelente inserto para acabamento de aço inoxidável 304 em equipamentos para indústria alimentar. A geometria SS elimina completamente o gume postico e a qualidade superficial é consistente em toda a produção."
Frequently Asked Questions
💡 Stainless Steel Machining Tips – Tungaloy MPJ Series Grade Guide
- MPJ300 (PVD TiAlSiN): Highest speed stainless finishing. Use when Vc > 200 m/min on 304/316. Maximum wear resistance, lower toughness.
- MPJ350 (PVD TiAlSiN) — This Product: Best balance for stainless finishing. Optimal BUE resistance, wear resistance, and toughness for 304, 316L, duplex, and 17-4PH.
- MPJ400 (PVD TiAlSiN): More toughness than MPJ350. Use for stainless semi-finishing with light interrupted cuts or variable stock.
- T9115 (PVD TiAlN): General-purpose finishing grade. Good for stainless but inferior BUE resistance vs. MPJ350. Use when both steel and stainless are machined with the same insert.
- AH725 (CVD): For stainless semi-finishing to roughing at higher feeds. CVD coating is less effective against BUE than PVD — use only when toughness is the priority.
- Chipbreaker guide for stainless: SS = finishing (fn 0.05–0.18, anti-BUE priority) | TSF = general finishing (fn 0.05–0.20) | TM = semi-finishing (fn 0.15–0.35). Always use SS chipbreaker when BUE is a problem.
- Golden rule for stainless: Sharp insert + low feed + adequate depth + continuous cutting + flood coolant = success. Never compromise on any of these five factors.
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.