Need reliable CNC Turning 4142 Alloy Steel? VT machining machines 4142 Alloy Steel to tight tolerances and consistent quality. As a material, 4142 Alloy Steel is high-strength and hardenable; we adapt feeds, speeds and tooling to suit.
CNC Turning Capability for 4142 Alloy Steel
- Cr-Mo / Ni-Cr-Mo grades
- High strength & hardenability
- Tolerance to ±0.01 mm
- Heat-treatable to 30–55 HRC
4142 Alloy Steel Material Data
| Density | 7.85 g/cm³ |
|---|---|
| Tensile strength | 655–1020 MPa |
| Yield strength (0.2%) | 415–900 MPa |
| Hardness | 197–302 HB |
| Melting point | 1416 °C |
| Thermal conductivity | 42.6 W/m·K |
| Thermal expansion | 12.3 ×10⁻⁶/K |
| Electrical conductivity | 8% |
| Machinability (C36000 = 100%) | 65% (annealed) |
| Grades we run | 4140, 4340, 8620, 20CrMnTi, 42CrMo4, 20MnCr5 |
Published typical values for 4140 (Q&T). Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
Heat treatment moves the part. Anything held tighter than ±0.02 mm is machined soft, hardened, then ground or hard-turned to final size.
Machining 4142 Alloy Steel with CNC Turning
When turning 4142 Alloy Steel, machinability is good in annealed condition; machined soft then heat-treated to final hardness. Our process plan reflects this so the finished part holds its tolerances without distortion or poor finish.
Documented parameters for 4142 Alloy Steel mean predictable cycle times and stable, repeatable results.
Achievable Tolerances for CNC Turning 4142 Alloy Steel
| Feature | Standard | Precision |
|---|---|---|
| Outside diameter | ±0.05 mm | ±0.005 mm |
| Bore diameter | H9 | H6 |
| Length / shoulder position | ±0.10 mm | ±0.020 mm |
| Concentricity OD to ID | 0.05 mm TIR | 0.010 mm TIR |
| Roundness | 0.02 mm | 0.005 mm |
| Thread class | 6g / 2A | 4h / 3A |
| Surface finish, as turned | Ra 1.6 µm | Ra 0.4 µm |
Standard is what a normal quotation assumes. Precision is available on nominated features and is priced separately, because it needs extra setups, in-process gauging and CMM verification. Call out only the features that need it — blanket-tightening a drawing is the single most common reason a quote comes back expensive.
Design Tips for CNC Turning 4142 Alloy Steel
Small design adjustments often cut cost and lead time. Consistent diameters, standard thread forms and avoiding extremely long, slender features help 4142 Alloy Steel turned parts stay concentric and economical. If you send your model early, we will return practical DFM feedback before you commit to production.
Secondary Operations & Finishing
Most 4142 Alloy Steel parts need some finishing, which we manage in-house or through vetted partners. Options include deburring and edge-breaking, heat treatment, surface grinding, polishing, and plating or anodising for corrosion resistance and appearance. Give us the finished-part requirement and we will sequence every operation correctly.
CNC Turning Tolerances & Surface Finish
Turned 4142 Alloy Steel holds diameter tolerances to about ±0.005 mm with concentricity within 0.01 mm and good roundness. Turned finishes of Ra 0.4–0.8 µm are achievable with finishing passes and sharp tooling.
Exact achievable figures depend on the alloy, the feature size and the part geometry. Tell us which dimensions are critical and we will advise feasibility up front.
CNC Turning Quality & Inspection
Quality is built in, not inspected on. We monitor key features during the run and confirm them at final inspection, with CMM verification available for tight tolerances. We provide the inspection and traceability records your quality system requires.
Why 4142 Alloy Steel?
Customers select 4142 Alloy Steel for CNC Turning because it is high-strength and hardenable. We handle grade verification and any required heat treatment or finishing.
Applications of CNC Turning 4142 Alloy Steel
4142 Alloy Steel parts made this way are found throughout aerospace, medical, automotive, electronics and industrial equipment. Prototype, bridge and production volumes are all welcome.
How to Order CNC Turning 4142 Alloy Steel
Starting your project takes one email. Send your CAD or 2D drawing, the 4142 Alloy Steel grade and condition, the quantity and any finish or inspection requirements. We respond quickly with price, lead time and any DFM notes, in clear English.
Finishing Options for 4142 Alloy Steel
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| Through hardening | — | 30–55 HRC, ground afterwards for tight sizes |
| Case hardening (carburise) | 0.3–1.2 mm case | 58–62 HRC surface, tough core |
| Nitride | 0.1–0.5 mm | 900–1100 HV, minimal distortion |
| Black oxide | 1–2 µm | Cosmetic + light corrosion protection |
| Zinc / nickel plate | 5–25 µm | Corrosion protection |
| Deburr / edge break | 0.05–0.3 mm | All parts unless the drawing says otherwise |
| Bead blast | Ra 1.6–3.2 µm | Uniform matt finish, hides tool marks |
| Laser marking | — | Part number, lot code, data matrix |
No drawing yet? Build one in the browser.
Set the metal, dimensions and features, watch the 3D model update as you type, then switch to the 2D sheet to add dimensions and tolerances. Download it or send it straight to us with your RFQ.
What We Need to Quote CNC Turning 4142 Alloy Steel
- GeometrySTEP or IGES for the 3D model, plus a PDF drawing if you have tolerance callouts. A dimensioned sketch is enough to start.
- MaterialThe exact 4142 Alloy Steel grade and condition — temper, heat-treat state or hardness. If you are not sure, tell us the function and we will suggest one.
- QuantityPrototype count and the expected annual volume. Both change how the part is made and therefore what it costs.
- TolerancesWhich features are critical. Everything else runs to our standard tolerance, which is what keeps the price sensible.
- FinishSurface treatment, cosmetic requirements, and any faces that must be masked.
- DocumentsWhether you need a material certificate, dimensional report, FAIR or PPAP with the shipment.
Missing something from the list is not a problem — send what you have. We will come back with the specific questions rather than a generic form.
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.