VT machining offers CNC Turning for 40Cr Steel (GB/T 3077 / ~5140 / ~41Cr4 / SCr440), typically supplied Q&T. Chinese Cr steel, cheaper than 42CrMo with lower hardenability.
CNC Turning Notes for 40Cr Steel
40Cr Steel turns with good chip control at standard cutting data.
For estimating, a 100 × 100 × 10 mm block of 40Cr Steel weighs about 0.79 kg.
Starting Parameters for CNC Turning 40Cr Steel
| Cutting speed (carbide) | 135-240 m/min |
|---|---|
| Feed | 0.1-0.35 mm/rev |
| Spindle speed, Ø25 mm bar | 1720-3060 rpm |
| Insert / tool class | ISO P — CVD-coated carbide |
| Coolant | Emulsion (5-8%); dry is possible for interrupted cuts |
Starting values for 40Cr Steel, Q&T; optimised on the first article.
40Cr Steel Data Relevant to CNC Turning
| Equivalent designations | GB/T 3077 / ~5140 / ~41Cr4 / SCr440 |
|---|---|
| Key composition | C 0.37-0.44%, Cr 0.8-1.1% |
| Typical supply condition | Q&T |
| Hardness (typical) | ~28-32 HRC |
| Machinability rating | 60% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How 40Cr Steel Differs
Chinese Cr steel, cheaper than 42CrMo with lower hardenability.
Typical applications: Shafts, gears, bolts.
40Cr Steel vs Similar Grades
| 40Cr Steel | 42CrMo Steel | 20CrMnTi Steel | EN19 Steel | |
|---|---|---|---|---|
| Key composition | C 0.37-0.44%, Cr 0.8-1.1% | C 0.38-0.45%, Cr 0.9-1.2%, Mo 0.15-0.25% | C 0.17-0.23%, Cr 1-1.3%, Mn 0.8-1.1%, Ti | C 0.36-0.44%, Cr 0.9-1.2%, Mo 0.25-0.35% |
| Hardness | ~28-32 HRC | ~28-32 HRC | ~58-62 HRC case | ~28-32 HRC |
| Tensile (MPa) | ~980 Q&T | ~1080 Q&T | ~1080 core | ~850-1000 |
| Machinability % | 60 | 62 | 60 | 62 |
| Typical use | Shafts, gears, bolts | Gears, shafts, high-strength bolts | Automotive gears, shafts | Shafts, gears, studs |
More on CNC Turning Steel
Finishing options, quality documentation and general cnc turning guidance for all steel grades are on our CNC Turning Steel page.
No drawing yet? Sketch the part in our free 3D + 2D builder and send it with your RFQ.
Quoting CNC Turning 40Cr Steel
Send a STEP/IGES model or PDF drawing, confirm 40Cr Steel and its condition (we usually see it supplied Q&T), the quantity, critical tolerances and any finish or certificate requirements.
40Cr Steel in Other Processes
Related
Send the drawing, the 40Cr Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
Can VT machining make custom 40Cr Steel parts to my drawing?
Yes. 40Cr Steel turning is made to order from your CAD/2D drawing. Share your geometry, material grade, tolerance and quantity and we will confirm feasibility, lead time and pricing.
Which industries use CNC Turning 40Cr Steel parts?
CNC Turning 40Cr Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 40Cr Steel components are required.
What surface finish is achievable on 40Cr Steel with CNC Turning?
Surface finish on 40Cr Steel is controlled to your specification; we confirm the achievable Ra against your callout.
What material thickness or size range suits CNC Turning 40Cr Steel?
Turned 40Cr Steel parts are produced from bar or chuck stock across a wide diameter range.
Why is 40Cr Steel a good choice for CNC Turning?
40Cr Steel is strong, economical and widely available, which makes it well suited to CNC Turning. We tune the process to the alloy so the finished 40Cr Steel turning part meets your dimensional and functional requirements.
What tolerances can you hold for CNC Turning 40Cr Steel?
Achievable tolerances for 40Cr Steel turning depend on the alloy, geometry and feature size. Turning holds diameter tolerances to around ±0.005 mm with concentricity within 0.01 mm. Exact figures are confirmed against your drawing callouts.