Complete Cutting Parameter Reference Table: Steel P10–P50, Stainless M10–M40, Cast Iron K10–K40
If you work in turning or milling, you know the frustration of hunting through catalogs to find the right starting parameters. This reference consolidates cutting speeds, feed rates, and depth of cut for the three most common ISO material groups — P (Steel), M (Stainless Steel), and K (Cast Iron) — into one bookmark-worthy page. All values assume carbide inserts with CVD or PVD coatings on standard CNC lathes and machining centers.
Use these as starting points. Always adjust based on machine rigidity, workpiece setup, coolant delivery, and actual chip formation.
How to Read This Table
- Vc (m/min) — Cutting speed at the tool tip. Multiply by π×D to convert to RPM.
- f (mm/rev) — Feed per revolution for turning. Higher values = roughing.
- ap (mm) — Depth of cut (radial engagement for turning).
- Roughing = heavy stock removal, interrupted cuts acceptable.
- Finishing = light cuts, tight tolerances, good surface finish.
ISO P — Steel (Carbon, Alloy, Tool Steel)
| Material Condition | ISO Group | Roughing Vc (m/min) | Roughing f (mm/rev) | Roughing ap (mm) | Finishing Vc (m/min) | Finishing f (mm/rev) | Finishing ap (mm) | Recommended Korloy Grade | Competitor Equivalent |
|---|---|---|---|---|---|---|---|---|---|
| Low Carbon Steel (free-cutting, ≤0.25% C) | P10–P20 | 280–350 | 0.25–0.45 | 2.0–4.0 | 380–500 | 0.10–0.20 | 0.3–1.0 | Korloy PC5300 (CVD TiCN/Al₂O₃) | Sandvik 4225, Kennametal KCP25 |
| Medium Carbon Steel (0.25–0.55% C) | P20–P30 | 220–300 | 0.20–0.40 | 2.0–4.0 | 320–420 | 0.10–0.20 | 0.3–1.0 | Korloy PC5335 (CVD) | Sandvik 4325, Tungaloy T9115 |
| High Carbon / Alloy Steel (0.55–0.85% C) | P30–P40 | 180–250 | 0.15–0.35 | 1.5–3.5 | 280–360 | 0.08–0.18 | 0.2–0.8 | Korloy PC5400 (CVD) | Sandvik 4425, Kennametal KCP40 |
| Hardened / Tool Steel (38–55 HRC) | P40–P50 | 100–170 | 0.10–0.25 | 1.0–2.5 | 180–250 | 0.06–0.12 | 0.1–0.5 | Korloy PC3545 (PVD AlTiN) | Sandvik 4435, Sumitomo AC8025 |
| Case-Hardened Steel (>55 HRC, hardened layer) | P50 | 80–130 | 0.08–0.18 | 0.5–1.5 | 130–180 | 0.04–0.10 | 0.1–0.3 | Korloy NC3225 (PVD TiAlN, CBN edge prep) | Kennametal KB5625, Sandvik 7015 |
Notes: For low carbon steels with long stringy chips, use a chipbreaker with positive geometry (Korloy HM or MP chipbreaker). For alloy steels with forging scale, reduce Vc by 15–20% on the first pass.
ISO M — Stainless Steel (Austenitic, Ferritic, Martensitic, Duplex)
| Material Condition | ISO Group | Roughing Vc (m/min) | Roughing f (mm/rev) | Roughing ap (mm) | Finishing Vc (m/min) | Finishing f (mm/rev) | Finishing ap (mm) | Recommended Korloy Grade | Competitor Equivalent |
|---|---|---|---|---|---|---|---|---|---|
| Austenitic SS (304, 316, 321 — soft annealed) | M10–M20 | 170–240 | 0.20–0.35 | 2.0–3.5 | 250–340 | 0.10–0.18 | 0.3–1.0 | Korloy PC215K (PVD TiAlN) | Sandvik 2220, Kennametal KCU25 |
| Austenitic SS (work-hardened or heavy interrupted) | M20–M30 | 130–190 | 0.15–0.30 | 1.5–3.0 | 200–270 | 0.08–0.15 | 0.2–0.8 | Korloy PC2507 (CVD Al₂O₃) | Sandvik 2325, Tungaloy T6130 |
| Ferritic / Martensitic SS (410, 420, 430) | M10–M20 | 200–280 | 0.20–0.40 | 2.0–4.0 | 280–380 | 0.10–0.20 | 0.3–1.0 | Korloy PC5300 / PC215K | Sandvik 2220 / 4225 |
| Duplex / Super Duplex SS (2205, 2507) | M30–M40 | 100–160 | 0.12–0.25 | 1.0–2.5 | 160–220 | 0.06–0.12 | 0.2–0.7 | Korloy PC2507 (CVD) | Sandvik 2330, Kennametal KCU30 |
| Precipitation-Hardened SS (17-4 PH, aged) | M20–M30 | 120–180 | 0.12–0.25 | 1.0–2.5 | 180–240 | 0.06–0.14 | 0.2–0.6 | Korloy PC3545 (PVD) | Sumitomo AC8025, Sandvik 2235 |
Notes: Austenitic stainless steels work-harden rapidly — never dwell; maintain continuous feed. High-pressure coolant (minimum 70 bar) recommended for chip control in deep cavities. PVD-coated grades give sharper cutting edges and reduce built-up edge (BUE).
ISO K — Cast Iron (Gray, Nodular, Compacted Graphite)
| Material Condition | ISO Group | Roughing Vc (m/min) | Roughing f (mm/rev) | Roughing ap (mm) | Finishing Vc (m/min) | Finishing f (mm/rev) | Finishing ap (mm) | Recommended Korloy Grade | Competitor Equivalent |
|---|---|---|---|---|---|---|---|---|---|
| Gray Cast Iron (GJL-200 to GJL-300, ≤220 HB) | K10–K20 | 250–350 | 0.25–0.50 | 2.5–5.0 | 380–500 | 0.10–0.22 | 0.3–1.2 | Korloy KC5305 (CVD Al₂O₃) | Sandvik 3210, Kennametal KCK15 |
| Gray Cast Iron (GJL-300+, hard skin, ≥250 HB) | K20–K30 | 180–260 | 0.20–0.40 | 2.0–4.0 | 280–380 | 0.08–0.18 | 0.2–0.8 | Korloy KC5405 (CVD) | Sandvik 3225, Tungaloy T5115 |
| Nodular / Ductile Iron (GJS-400 to GJS-600) | K20–K30 | 200–290 | 0.20–0.40 | 2.0–4.0 | 300–400 | 0.10–0.20 | 0.3–1.0 | Korloy KC5335 (CVD) | Sandvik 3225, Kennametal KCK25 |
| Nodular Iron (GJS-700+, pearlitic, ≥300 HB) | K30–K40 | 150–220 | 0.15–0.30 | 1.5–3.0 | 220–300 | 0.08–0.16 | 0.2–0.7 | Korloy KC5405 (CVD) | Sandvik 3235, Sumitomo AC420K |
| Compacted Graphite Iron (CGI, GJV-350 to GJV-500) | K20–K30 | 180–260 | 0.18–0.35 | 1.5–3.5 | 260–340 | 0.08–0.16 | 0.2–0.8 | Korloy KC5335 (CVD) | Sandvik 3225, Kennametal KCK25 |
Notes: Cast iron produces short discontinuous chips and can often be machined dry or with compressed air blast. Use wiper geometry inserts for finishing to achieve Ra ≤ 0.8 µm. The hard skin (chill layer) on castings may require 20–30% lower Vc on first pass.
Quick RPM Conversion Formula
To convert cutting speed to spindle RPM:
n = (Vc × 1000) / (π × D)
Where:
n = spindle speed (rev/min)
Vc = cutting speed (m/min)
D = workpiece or tool diameter (mm)
Example: Turning a 60 mm diameter shaft in medium carbon steel at Vc = 280 m/min → n = (280 × 1000) / (3.1416 × 60) = 1,485 RPM
Cross-Grade Quick Reference
| Korloy Grade | ISO Application | Coating Type | Sandvik Equivalent | Kennametal Equivalent | Sumitomo Equivalent |
|---|---|---|---|---|---|
| PC5300 | P10–P30 | CVD TiCN/Al₂O₃ | 4225 | KCP25 | AC8025P |
| PC5335 | P20–P40 | CVD TiCN/Al₂O₃ | 4325 | KCP35 | AC8035P |
| PC5400 | P30–P50 | CVD TiCN/Al₂O₃ | 4425 | KCP40 | AC8045P |
| PC3545 | P30–P50 / M20–M30 | PVD AlTiN | 4435 | KCU30 | AC8025 |
| PC215K | M10–M20 | PVD TiAlN | 2220 | KCU25 | AC6020P |
| PC2507 | M20–M40 | CVD Al₂O₃/TiCN | 2325 | KCU30 | AC6030P |
| KC5305 | K10–K20 | CVD Al₂O₃/TiCN | 3210 | KCK15 | AC410K |
| KC5335 | K20–K30 | CVD Al₂O₃/TiCN | 3225 | KCK25 | AC420K |
| KC5405 | K30–K40 | CVD TiCN/Al₂O₃ | 3235 | KCK35 | AC430K |
Parameter Adjustment Rules of Thumb
- Interrupted cuts: Reduce Vc by 20–30%, use tougher grade (step up one ISO sub-group).
- Poor rigidity / long overhang: Reduce ap by 30–50%, maintain feed for chip control.
- High-pressure coolant (70–150 bar): Increase Vc by 10–15%, improve chip evacuation.
- Dry machining cast iron: Keep Vc as listed; ensure dust extraction. CVD coatings mandatory.
- Hard material >45 HRC: Use CBN inserts, Vc 100–200 m/min, light ap 0.1–0.5 mm.
Need help selecting the right insert for your application? The team at hooguu.com specializes in Korloy carbide inserts and can recommend the optimal grade and chipbreaker for your specific material and operation. Browse our full Korloy catalog or contact us for a free cutting parameter consultation.
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