CNC Machining Materials

Steel

At a glance

Processes

CNC Mill
CNC Lathe

Lead Time

As fast as 2 days

Tolerance

With drawing: as low as +/- 0.005 mm
No drawing: ISO 2768 medium

Price

$$$

Applications

Fixtures and mounting plates; draft shafts, axles, torsion bars

Alloys

4140, 4130, A514, 4340

Carbon Steel Types

1018 Low Carbon, 1045 Carbon, Zinc-Galvanized Low-Carbon

Finishing Options

Black Oxide, ENP, Electropolishing, Media Blasting, Nickel Plating, Powder Coating, Tumble Polishing, Zinc Plating

About the material

1018 Steel is a mild, low carbon steel that is machinable, weldable and useful where high-strength is not required, such as fixtures and mounting plates. It is magnetic and heat treatable.

4140 alloy steel is generally harder and stronger than carbon steel. Additionally, it provides high impact resistance, fatigue strength, and torsional strength, which makes 4140 a great choice for drive shafts, axles, and torsion bars. In terms of hardening, 4140 can be hardened using a variety of methods such as cold working, or heating and quenching.

1045 Carbon Steel is stronger than low carbon steel (1018 Steel) but is easy to machine. It is heat treatable and can be used for bolts, studs and shafts.

4130 Alloy Steel is similar to 4140 Alloy Steel but offers better weldability and has a slightly lower carbon content. It is best suited for gears and other structural applications.

Zinc-Galvanized Low-Carbon Steel has an outer coating of zinc to improve corrosion resistance. It is important to note that the coating will only be present on non-machined areas.

A514 Alloy Steel is a high strength, low alloy steel that is used mainly in structural applications. It is weldable, heat treatable and is best suited for supporting heavy loads.

4340 Alloy Steel is a medium carbon, low alloy steel that is highly useful in environments involving extreme impact, heat, and wear.

Material Properties

1018 Low Carbon Steel

Yield Strength (tensile)

60,000 psi

Elongation at Break

15%

Hardness

Rockwell B90

Density

7.87 g/㎤
0.284 lbs / cu. in.

4140 Steel

Yield Strength (tensile)

60,000 psi

Elongation at Break

21%

Hardness

Rockwell C15

Density

7.87 g/㎤
0.284 lbs / cu. in.

1045 Carbon Steel

Yield Strength (tensile)

77,000 psi

Elongation at Break

19%

Hardness

Rockwell B90

Density

7.87 g/㎤
0.284 lbs / cu. in.

4130 Steel

Yield Strength (tensile)

122,000 psi

Elongation at Break

13%

Hardness

Rockwell C20

Density

7.87 g/㎤
0.284 lbs / cu. in.

Zinc-Galvanized Low-Carbon Steel

Yield Strength (tensile)

30,000 psi

Elongation at Break

23%

Hardness

Rockwell B65

Density

7.87 g/㎤
0.284 lbs / cu. in.

A514 Steel

Yield Strength (tensile)

100,000 psi

Elongation at Break

18%

Hardness

Rockwell C20

Density

7.87 g/㎤
0.284 lbs / cu. in.

4340 Steel

Yield Strength (tensile)

122,000 psi

Elongation at Break

13%

Hardness

Rockwell C20

Density

7.87 g/㎤
0.284 lbs / cu. in.

Material Finish

The finish of Steel is similar to that of Stainless Steel, generally shiny in appearance and slightly darker than aluminum alloys.

Alloy and carbon steels can be media blasted, or they can be electropolished to a variety of surface finishes.

Design Recommendations

Min Wall Thickness

0.5 mm

Min End Mill Size

0.8 mm (0.03 in)

Min Drill Size

0.5 mm (0.02 in)

Max Part Size

1200 x 500 x 152 mm [x,y,z] (mill)
152 x 394 mm [d,h] (lathe)

Undercuts

Square profile, full radius, dovetail profiles

Radii : Depth

Depth must not exceed 12x drill bit diameter.
For end mills, depth must not exceed 10x tool diameter.

Cost Saving Tip

To reduce costs, limit the number of part setups, the number of inspection dimensions or tight tolerances, and deep pockets with small radii.

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