Workpiece material / Tool steel

D2 Tool Steel speeds and feeds

Starting surface speeds and chip loads for milling D2 Tool Steel. Every value below is cross-checked against published sources and linked, so you can re-verify it yourself. Starting points, not limits.

Identification

W.Nr: 1.2379
DIN / EN: X153CrMoV12
AISI / SAE: D2
UNS: T30402
Brands: Bohler K110, Uddeholm Sverker 21, JIS SKD11
Hardness: 220-250 HB
Condition: Soft-annealed (about 220-250 HB) - the state D2 is machined in before hardening.
ISO 513 group: P

Cutting data / sourcedClick any source to check

Value	Used	Provider readings (each linked)
Surface speed, HSS (estimated)	40 SFM	40 Uddeholm Sverker 21 (D2 / 1.2379) cutting data recommendations (PDF) - uncoated HSS end milling 12-17 m/min (40-56 SFM); single source, flagged estimated
Surface speed, carbide	200 SFM	200 Machining Doctor - D2 tool steel machining data sheet (SFM, ISO group) - milling, coated carbide, annealed; published range 200-280 SFM 230 Uddeholm Sverker 21 (D2 / 1.2379) cutting data recommendations (PDF) - solid carbide end/slot milling 70-100 m/min (230-330 SFM), 5-10 mm cutter
Chip load @ 0.25" (estimated)	0.0006 in/tooth	0.0006 Uddeholm Sverker 21 (D2 / 1.2379) cutting data recommendations (PDF) - solid carbide, 5-10 mm cutter: 0.01-0.02 mm/tooth; grade-specific, not cross-checked

Chip load by end-mill diameter in/tooth

0.125"	0.25"	0.5"
0.0003	0.0006	0.0012

Cutting-power model class-typical

Constant	Value	Readings
Kc1.1 (specific cutting force) (estimated)	1,950 N/mm2	1,950 Sandvik Coromant - specific cutting force (Kc) by ISO material group - ISO P tool-steel group-typical Kc1.1; not tuned to this grade
mc (chip-thickness exponent) (estimated)	0.25	ISO P group-typical - see notes
Unit power (estimated)	1.50 HP/(in3/min)	ISO P group-typical - see notes

The power-model constants (Kc1.1, mc, unit power) are class-typical values for the ISO P group, used only for a rough spindle-power estimate. Only their relative ordering and internal consistency are verified, never tuned to match any vendor.

Notes

D2 (1.2379 / X153CrMoV12) is a high-carbon high-chromium cold-work tool steel, machined in the soft-annealed condition (about 220-250 HB) before hardening. Surface speeds agree closely across Machining Doctor (200-280 SFM for milling) and Uddeholm Sverker 21 (solid carbide 70-100 m/min); the shipped 200 SFM is the conservative low end. Chip loads are Uddeholm's grade-specific solid-carbide feeds per tooth (0.01-0.02 mm/tooth at a 5-10 mm cutter), which run lighter than plain alloy steel because D2 is abrasive and work-hardens - do not take light skimming cuts. The power-model constants (Kc1.1, mc, unit power) are ISO P tool-steel class-typical values for a rough power estimate only, not tuned to this grade. Verify against your tool maker before committing.

Verify this yourself

Every number above links to the provider that publishes it. Open two or more and confirm they agree with what is shown here. Full source list:

Take these into the feeds and speeds calculator for RPM, feed and power. Start a little under these numbers on a light or flexible setup.