VT machining specialises in CNC Broaching 40Cr Steel. Because 40Cr Steel is strong, economical and widely available, and its machinability is good to excellent depending on carbon content; free-machining grades cut cleanly, we plan each job around the grade to protect accuracy and surface quality.
CNC Broaching Capability for 40Cr Steel
- Carbon/low-alloy grades
- Economical & weldable
- Tolerance to ±0.02 mm
- Hardenable by heat treat
40Cr Steel Material Data
| Density | 7.85 g/cm³ |
|---|---|
| Tensile strength | 585 MPa |
| Yield strength (0.2%) | 450 MPa |
| Hardness | 170 HB |
| Melting point | 1420–1460 °C |
| Thermal conductivity | 51.9 W/m·K |
| Thermal expansion | 11.5 ×10⁻⁶/K |
| Electrical conductivity | 9% |
| Machinability (C36000 = 100%) | 57% |
| Grades we run | 1018, 1045, 1215, A36, S45C, St37, 4140 (see alloy steel) |
Published typical values for 1045. Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
Rust. Bare steel flash-rusts within hours in a humid container, so parts are oiled or passivated before packing unless you specify otherwise.
Machining 40Cr Steel with CNC Broaching
40Cr Steel behaves predictably under CNC Broaching once parameters are dialled in: machinability is good to excellent depending on carbon content; free-machining grades cut cleanly, and we tune the operation accordingly.
We hold reference parameters for this grade, so repeat orders of 40Cr Steel run consistently from one batch to the next.
Achievable Tolerances for CNC Broaching 40Cr Steel
| Feature | Standard | Precision |
|---|---|---|
| Linear dimension (< 100 mm) | ±0.05 mm | ±0.010 mm |
| Linear dimension (100–300 mm) | ±0.10 mm | ±0.025 mm |
| Hole diameter (reamed) | H9 | H7 |
| True position of hole pattern | ±0.10 mm | ±0.025 mm |
| Flatness over 100 mm | 0.05 mm | 0.015 mm |
| Perpendicularity | 0.10 mm | 0.020 mm |
| Surface finish, as machined | 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.
Secondary Operations & Finishing
Finished 40Cr Steel parts can move straight into secondary operations under one roof. Typical add-ons are deburring, passivation, anodising, plating, blasting, polishing and laser marking. We coordinate the whole chain so you receive complete, inspection-ready parts.
CNC Broaching Quality & Inspection
We control quality throughout the process, not just at the end. In-process checks plus final inspection — including CMM where specified — keep every 40Cr Steel part to print. Inspection reports, material certificates and first-article documentation can be supplied on request.
Design Tips for CNC Broaching 40Cr Steel
We are happy to suggest design tweaks that improve manufacturability. Generous internal radii, sensible pocket depth-to-width ratios and avoiding very thin unsupported walls all reduce cost and improve accuracy in 40Cr Steel. If you send your model early, we will return practical DFM feedback before you commit to production.
Why 40Cr Steel?
40Cr Steel is chosen when a part needs what this grade offers — it is strong, economical and widely available. We confirm the grade and any temper or heat-treat condition with you before machining.
CNC Broaching Tolerances & Surface Finish
For CNC Broaching, dimensional and positional tolerances around ±0.01 mm are routine, tightening toward ±0.005 mm on precision setups. Surface finish on machined faces typically falls in the Ra 0.4–1.6 µm range depending on tooling and pass strategy.
Final tolerances are governed by the material's behaviour, wall thickness and overall stiffness. We give honest DFM feedback if a callout would be costly or better achieved another way.
Applications of CNC Broaching 40Cr Steel
Customers order CNC Broaching 40Cr Steel components for everything from instrumentation to structural and functional assemblies. Whether you need a single prototype or recurring production volume, the same process discipline applies.
How to Order CNC Broaching 40Cr Steel
Getting a quote is simple. Share your model, the material grade, your quantity and target tolerances. You receive a clear quotation with lead time and honest manufacturability feedback.
Finishing Options for 40Cr Steel
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| Black oxide | 1–2 µm | Mild corrosion resistance, no dimensional change |
| Zinc plate + clear/yellow | 5–12 µm | ASTM B633, general corrosion protection |
| Nickel plate (electroless) | 10–25 µm | Uniform in bores, 500 HV after bake |
| Phosphate | 5–10 µm | Paint key, mild lubricity |
| Powder coat | 60–120 µm | RAL colours |
| 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 Broaching 40Cr 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 40Cr 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.
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
How clean are the edges produced by CNC Broaching on 40Cr Steel?
Machined 40Cr Steel edges are clean and to specification; edge-break or deburring is added when your drawing calls for it.
What material thickness or size range suits CNC Broaching 40Cr Steel?
We machine 40Cr Steel across a broad size range; share your part envelope for confirmation.
Does CNC Broaching 40Cr Steel require dedicated tooling?
Most 40Cr Steel machining work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
What is CNC Broaching 40Cr Steel and how is it done?
CNC Broaching 40Cr Steel refers to broaching pushes a toothed tool through or across a part to form keyways, splines and internal profiles. Applied to 40Cr Steel — strong, economical and widely available — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.
What tolerances can you hold for CNC Broaching 40Cr Steel?
Achievable tolerances for 40Cr Steel machining depend on the alloy, geometry and feature size. Milling holds positional and dimensional tolerances to around ±0.01 mm, tighter with precision setups. Exact figures are confirmed against your drawing callouts.