Starting cutting speed in m/min and sfm, feed in mm/rev and ipr, the carbide grade class and the setup by operation for AISI 4340 (34CrNiMo6). The numbers are the published P10 Alloy steel sub-group starting band; the designations are on the cross-reference page.
| Item | Value |
|---|---|
| ISO 513 group | P Steel |
| Sub-group | P10 Alloy steel |
| Sub-group hardness / condition | 180–280 HB |
| Category | Alloy steel (CrNiMo) |
| EN / Werkstoffnummer | 34CrNiMo6 · 1.6582 |
Hardness is the range published for the whole P10 Alloy steel sub-group on our material guide; the delivery condition of your AISI 4340 may sit anywhere inside it or outside it.
| Condition | Vc m/min | Vc sfm | Feed mm/rev | Feed ipr |
|---|---|---|---|---|
| P10 Alloy steel, 180–280 HB | 200–300 | 655–985 | 0.10–0.40 | .004–.016 |
Sub-group starting values for carbide inserts, from P10 Alloy steel. They describe the whole sub-group and are not tuned to AISI 4340. sfm and ipr are converted from the metric values (1 m/min = 3.281 sfm, 25.4 mm = 1 in). The published band is per sub-group, not per operation; the table below gives the setup by operation. Convert Vc to spindle speed with the speeds & feeds calculator, and see the speeds & feeds guide for the ISO P group range.
| Operation | Geometry | Coating family | Coolant | First check |
|---|---|---|---|---|
| Roughing | Negative geometry, economical; medium chipbreaker | CVD-coated carbide | Per process | Chipbreaker: stringy chips mean feed too low or wrong breaker |
| Finishing | Positive geometry, medium chipbreaker | CVD-coated carbide | Per process | Built-up edge at low speed: raise Vc, sharper edge |
| Interrupted cut | Negative geometry with a robust edge | CVD-coated carbide | Per process | Crater wear at high speed: ease Vc |
| Low rigidity / thin wall | Positive geometry for low-rigidity work | CVD-coated carbide | Per process | Flank wear: balance Vc and grade hardness |
Setup rows are the selection table of the P10 Alloy steel guide. They carry no speeds, so they do not change the starting band above.
Same sub-group, same starting band: AISI 4140 · AISI 4130 · AISI 52100 · AISI 6150 · 30CrNiMo8 · 31CrMoV9
CVD-coated carbide, P15–P25 general; tougher P25–P35 for roughing, P10–P20 for finishing. Annealed alloy steel (4140 / 4340, ~180–280 HB) takes higher speeds than its heat-treated form.
The P, M, K, N, S or H number inside a grade range describes what the grade is built for, not the workpiece sub-group number, and the two scales must not be matched to each other. We name no single grade here: none of our published sources ties a named grade to this alloy. Pick by ISO class, then compare what the makers publish on the ISO P grade list and in the grade chart.
EN 34CrNiMo6, Werkstoffnummer 1.6582, US AISI 4340 (UNS G43400), JIS SNCM439 (nearest). The full table, with the nearest-match flags, is on the 34CrNiMo6 / AISI 4340 cross-reference page.
High-strength CrNiMo steel, usually cut quenched and tempered: tough, stringy chips and real heat at the edge. A tough P25-position coated grade and stable chip control beat chasing speed.
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The published starting band for the P10 Alloy steel sub-group is 200–300 m/min (655–985 sfm) at 0.10–0.40 mm/rev (.004–.016 ipr). It is a starting band for the whole sub-group, not a value tuned to AISI 4340, so confirm on a sample part and adjust for condition, tool and rigidity.
CVD-coated carbide, P15–P25 general; tougher P25–P35 for roughing, P10–P20 for finishing. Annealed alloy steel (4140 / 4340, ~180–280 HB) takes higher speeds than its heat-treated form. Pick the grade by ISO class rather than by brand name, then confirm the exact grade for your condition. We name no single grade here because none of our published sources ties a named grade to this alloy.
EN 34CrNiMo6 (Werkstoffnummer 1.6582); US: AISI 4340 (UNS G43400); JIS: SNCM439 (nearest). Entries marked nearest are the closest commonly-cited counterpart, not a same-composition equivalent.
The advisor compares what the makers publish for your material and operation and shows the source behind each answer, or tells you it could not verify.