X105CrMo17 is the same material your supplier may list as AISI 440C or JIS SUS440C. This page maps the designations across standards and gives the ISO M-group machining starting point, brand-neutral.
| System | Designation |
|---|---|
| EN (EU) | X105CrMo17 |
| Werkstoffnummer | 1.4125 |
| AISI / ASTM / UNS (US) | AISI 440C (UNS S44004) |
| JIS (Japan) | SUS440C |
Compiled from the public standard designation systems (EN 10027, SAE/AISI, ASTM, UNS, JIS). Entries marked “nearest” are the closest commonly-cited counterpart, not a drop-in equivalent. Always verify against the material certificate.
Bearing-grade stainless: annealed it is abrasive from carbide volume, hardened to 58+ HRC it is hard-turning work. Expect tool life closer to D2 than to 420.
| ISO group | Starting Vc (coated carbide, turning) | Feed fn |
|---|---|---|
| M M · Stainless steel | 120–220 m/min · 395–720 sfm | 0.15–0.4 mm/rev · .006–.016 ipr |
Group-level starting range from our speeds & feeds guide; convert to RPM with the speeds & feeds calculator. Condition, subgroup and operation shift the number — the material page has the detail: ISO M · High-carbon martensitic stainless.
Related materials: AISI 410 / 1.4006 · AISI 420 / 1.4021 · AISI 430 / 1.4016 · AISI 431 / 1.4057 · AISI 416 / 1.4005
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X105CrMo17 (Werkstoffnummer 1.4125) corresponds to AISI 440C (UNS S44004). In JIS terms the counterpart is SUS440C.
It is an ISO M-group material, so the starting window is 120–220 m/min · 395–720 sfm at 0.15–0.4 mm/rev · .006–.016 ipr for coated-carbide turning, adjusted for condition and operation. For a grounded, brand-neutral pick — grade, geometry and cutting data across 13 brands — ask the advisor.
They designate the same composition under different systems, but the drawing standard governs: certificates, tolerances and delivery-condition requirements differ between standards even for equivalent chemistry. Substitute only with the certificate in hand.
Knowing the material is half the job; picking the grade and cutting data for the operation is the other half. That is what the advisor does, grounded in catalog data and honest when there is no verified match.