VT machining offers CNC Turning for 4142 Alloy Steel (UNS G41420 / ~42CrMo4), typically supplied pre-hardened (28-32 HRC). Slightly higher carbon than 4140; commonly stocked pre-hardened.
CNC Turning Notes for 4142 Alloy Steel
4142 Alloy Steel turns with good chip control at standard cutting data.
For estimating, a 100 × 100 × 10 mm block of 4142 Alloy Steel weighs about 0.79 kg.
Starting Parameters for CNC Turning 4142 Alloy Steel
| Cutting speed (carbide) | 120-200 m/min |
|---|---|
| Feed | 0.1-0.3 mm/rev |
| Spindle speed, Ø25 mm bar | 1530-2550 rpm |
| Insert / tool class | ISO P — CVD-coated carbide |
| Coolant | Emulsion (6-8%) |
Starting values for 4142 Alloy Steel, Pre-hardened (28-32 HRC); optimised on the first article.
4142 Alloy Steel Data Relevant to CNC Turning
| Equivalent designations | UNS G41420 / ~42CrMo4 |
|---|---|
| Key composition | C 0.40-0.45%, Cr 0.8-1.1%, Mo 0.15-0.25% |
| Typical supply condition | Pre-hardened (28-32 HRC) |
| Hardness (typical) | ~28-32 HRC |
| Machinability rating | 62% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How 4142 Alloy Steel Differs
Slightly higher carbon than 4140; commonly stocked pre-hardened.
Typical applications: Die holders, shafts, tooling.
4142 Alloy Steel vs Similar Grades
| 4142 Alloy Steel | 4140 Alloy Steel | 4340 Alloy Steel | 4130 Alloy Steel | |
|---|---|---|---|---|
| Key composition | C 0.40-0.45%, Cr 0.8-1.1%, Mo 0.15-0.25% | C 0.38-0.43%, Cr 0.8-1.1%, Mo 0.15-0.25% | C 0.38-0.43%, Ni 1.65-2%, Cr 0.7-0.9%, Mo | C 0.28-0.33%, Cr 0.8-1.1%, Mo 0.15-0.25% |
| Hardness | ~28-32 HRC | ~197 HB annealed; 28-32 HRC pre-hard | ~30-50 HRC Q&T | ~18-30 HRC |
| Tensile (MPa) | ~965 | ~655-1000 | ~745 annealed; up to ~1800 | ~670-900 |
| Machinability % | 62 | 66 | 57 | 70 |
| Typical use | Die holders, shafts, tooling | Shafts, gears, tooling, spindles | Aircraft landing gear, crankshafts, heavy shafts | Aircraft tubing, roll cages, fittings |
More on CNC Turning Alloy Steel
Finishing options, quality documentation and general cnc turning guidance for all alloy steel grades are on our CNC Turning Alloy Steel page.
No drawing yet? Sketch the part in our free 3D + 2D builder and send it with your RFQ.
Quoting CNC Turning 4142 Alloy Steel
Send a STEP/IGES model or PDF drawing, confirm 4142 Alloy Steel and its condition (we usually see it supplied pre-hardened (28-32 HRC)), the quantity, critical tolerances and any finish or certificate requirements.
4142 Alloy Steel in Other Processes
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Send the drawing, the 4142 Alloy Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
What is the typical lead time and minimum order for CNC Turning 4142 Alloy Steel?
CNC Turning prototypes for 4142 Alloy Steel can be produced quickly and scaled to series production. Send your drawing and quantity and we will advise lead time and any minimum order.
Which industries use CNC Turning 4142 Alloy Steel parts?
CNC Turning 4142 Alloy Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 4142 Alloy Steel components are required.
What surface finish is achievable on 4142 Alloy Steel with CNC Turning?
Surface finish on 4142 Alloy Steel is controlled to your specification; we confirm the achievable Ra against your callout.
Why is 4142 Alloy Steel a good choice for CNC Turning?
4142 Alloy Steel is high-strength and hardenable, which makes it well suited to CNC Turning. We tune the process to the alloy so the finished 4142 Alloy Steel turning part meets your dimensional and functional requirements.