CNC machined 4140 alloy steel industrial component at Fenva

Materials · CNC machining

Carbon & Alloy Steel CNC Machining

Carbon and alloy steel milled and turned to your drawing — 1018, 1045, 12L14, A36, 4140 and 4340 — on 3-, 4- and 5-axis equipment, with in-house heat treatment and corrosion-protective finishing, inspected in-house. ISO 9001 / IATF 16949 / AS9100D certified.

Quote in 48h Prototypes 10–15 business days Production 15–30 business days No minimum order

Carbon and alloy steel give you strength, stiffness and value, and they respond well to heat treatment for higher hardness, wear resistance and fatigue life. We mill and turn carbon steel (1018, 1045, A36), free-machining steel (12L14) and alloy steel (4140, 4340) to your drawing, and coordinate heat treatment — through-hardening, tempering, case-hardening and stress relief — in-house. Because steel is not corrosion-resistant on its own, we finish it: black oxide, zinc or nickel plating, phosphate or powder coat. Send a drawing and you get a line-item quote in 48 hours, one prototype or a production batch, with no minimum order.

Grades

Grades we run

Grade Type Why you pick it Parts
1018Low-carbon (mild) steelEasy to machine and weld, economical, case-hardens wellGeneral machined parts, brackets, studs, pins
12L14Free-machining (leaded)Best machinability in steel, fast cycles, fine turned finishFittings, fasteners, bushings, high-volume turned parts
1045Medium-carbon steelHigher strength, through-hardenable, good wear resistanceShafts, axles, spacers, gears, machine parts
A36Structural mild steelWeldable, economical structural gradeBase plates, frames, brackets, weldments
4140Chromoly alloy steelHigh strength and toughness, hardenable, excellent fatigue lifeShafts, gears, couplings, tooling, high-load fittings
4340Ni-Cr-Mo alloy steelVery high strength with deep hardenability and toughnessHigh-load shafts, heavy-duty drivetrain, demanding structural parts

These are the carbon and alloy steel grades we run most often. We also machine other grades on request.

Capability

What we can hold

  • 3-, 4- and 5-axis milling plus CNC turning, so shafts, gears and multi-face parts finish in fewer setups.
  • General tolerance ISO 2768-m as standard; down to ±0.005 mm on the features that need it.
  • Surface finish to about Ra 1.6 off the machine, finer on request.
  • Heat treatment coordinated in-house — through-hardening, tempering, case-hardening and stress relief — with DFM feedback before machining begins.
CNC machine cutting a steel component at Fenva Precision

Finishes for steel

As-machined, black oxide, zinc plating (clear or yellow), nickel and electroless nickel, phosphate (Parkerizing), powder coat and paint, plus oil and rust-preventive for shipping. Steel is not stainless, so a protective finish is usually specified.

See the Finish Library

Where it goes

Automotive and EV driveline, industrial machinery, tooling, jigs and fixtures, hydraulics, and high-load shafts, gears and structural parts.

Automotive CNC

Production parts

Steel parts we have made

Material and finish are taken from our production records.

Why Fenva

Why Fenva for steel

Machining + heat treat + finish

One source for machining, heat treatment and corrosion-protective finishing, so your steel part ships ready to use. No minimum order, prototype to production.

Triple-certified

AS9100D, ISO 9001 and IATF 16949, with material certs and heat-treat records on request.

We take full responsibility for what we machine

We machine strictly to your drawing and take full responsibility for the result.

Mini-FAQ

Steel machining, answered

Carbon or alloy steel?

Carbon steel (1018, 1045) for general parts and cost; alloy steel (4140, 4340) when you need higher strength, hardness and fatigue resistance.

Can you heat-treat?

Yes — through-hardening, tempering, case-hardening and stress relief, coordinated in-house, with a target hardness on request.

How do you stop it rusting?

Steel is not stainless, so we finish it: black oxide, zinc or nickel plating, phosphate or powder coat, plus rust-preventive oil for shipping.

Lead time?

Prototypes about 10 to 15 business days, production about 15 to 30, quote in 48 hours.

5-axis CNC machine cutting a steel component at Fenva Precision

Get started

Send your drawing for a 48-hour steel quote.

Upload your drawings for review and our engineering team will quote within 48 hours, no minimum order.

An NDA is available on request.