Reference Chart
Steel Feeds & Speeds Chart
Quick-look reference data for low-carbon, medium-carbon, alloy, and pre-hardened tool steel milling. Best used as a shop-floor starting chart before you validate DOC, rigidity, coolant, and cutter details in the calculator.
Validate Steel Milling Setup Values
Use this chart for a fast first pass. Then move to the steel calculator when cutter diameter, DOC, coolant plan, or machine rigidity need a setup-specific answer.
Reference handoff
Steel table handoff
Use this chart for steel reference ranges, then route grade-specific setup and operation changes through calculators.
Best starting point
Steel milling reference values for low-carbon, alloy, and pre-hardened grades.
Branch when
Turning, drilling, tapping, and high-hardness finishing need operation-specific validation.
Worked Formula Example Before Release
Worked example: 4140 coated-carbide roughing at 500 SFM with a 0.5 inch end mill is about 3,820 RPM. At 4 flutes and 0.003 inch chip load, feed is about 45.8 IPM before derating for engagement, tool stickout, coolant, and fixture rigidity. If machine power or rigidity forces an RPM cap, recompute real SFM from the capped RPM before approving the feed.
Low Carbon Steel (1018, A36)
Soft and gummy. Prone to built-up edge if not careful. Machines very easily.
| Tool Material | Operation | SFM Range | Chip Load (1/2" End Mill) |
|---|---|---|---|
| Coated Carbide | Roughing | 600 - 900 | 0.003" - 0.006" |
| Coated Carbide | Finishing | 800 - 1200 | 0.001" - 0.003" |
| HSS | General | 100 - 150 | 0.002" - 0.004" |
Alloy Steel (4140, 4340) - Annealed
The workhorse of engineering. Tough but machines cleanly with good chip control.
| Tool Material | Operation | SFM Range | Chip Load (1/2" End Mill) |
|---|---|---|---|
| Coated Carbide | Roughing | 400 - 650 | 0.0025" - 0.005" |
| Coated Carbide | Finishing | 600 - 800 | 0.001" - 0.002" |
| HSS | General | 70 - 100 | 0.002" - 0.003" |
Pre-Hardened / Tool Steel (P20, H13)
Hardness 30-45 HRC. Requires rigid setup and strict speed control to handle heat generation.
| Tool Material | Operation | SFM Range | Chip Load (1/2" End Mill) |
|---|---|---|---|
| Coated Carbide (AlTiN) | Roughing | 200 - 350 | 0.0015" - 0.003" |
| Coated Carbide (AlTiN) | Finishing | 300 - 450 | 0.0008" - 0.0015" |
Coating Guide: Steel
AlTiN / TiAlN
Color: Dark Grey / Violet
Best for Steel
High heat resistance (800°C+). Allows dry machining for chip evacuation.
TiCN (Titanium Carbonitride)
Color: Blue / Grey
Good Alternative
Lower friction than TiN. Good for stainless and harder steels.
Coolant Strategy Depends on Tooling and Operation
Many carbide steel milling jobs run well dry or with strong air blast because the heat leaves with the chip and thermal shock stays low.
Flood coolant is still common for HSS, deeper cavities, drilling, turning, or any workflow where temperature control improves consistency. The main rule is to avoid intermittent flood on already-hot carbide, because repeated heat shock can crack the edge.
Frequently Asked Questions
What SFM should I use for mild steel (1018/A36)?
For steel milling, this chart gives a first-pass window of 600–900 SFM for coated carbide roughing and 800–1,200 SFM for finishing. Use the steel calculator before release if tool diameter, engagement, or machine power materially change the setup.
What is the recommended chip load for milling steel?
For a 1/2-inch end mill, 0.002–0.005 IPT is a practical chart range for many steel milling jobs. Stay near the low end for tougher or harder grades, then confirm with the calculator when radial engagement or rigidity is limiting the cut.
How do I adjust speeds for hardened steel?
40–55 HRC: reduce SFM by 50–70%. Use AlTiN or TiSiN coated carbide. Above 55 HRC: CBN inserts or ceramics required.
What coatings work best for steel machining?
TiAlN is the standard. AlTiN for higher hardness. TiCN for tapping/threading. Multi-layer coatings extend life 2–3×.
Should I use flood coolant when machining steel?
Sometimes yes, sometimes no. Air blast is common for carbide milling, while flood or through-tool coolant is still useful for HSS, drilling, turning, or deeper heat-trapping cuts. What matters most is consistency and avoiding intermittent flood on hot carbide.