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Alloy Steel CNC Machining

Alloy steels contain other alloying elements along with carbon, resulting in improved solidity, toughness, fatigue and wear resistance.

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Alloy Steel CNC Machining

Alloy steel is one of the steel alloys containing different elements such as molybdenum, manganese, nickel, chromium, vanadium, silicon, and boron. These alloying components are included in increased stamina, solidity, wear resistance, and toughness. The amounts of alloying elements may range from 1 to 50%.

Common alloy steel types used for CNC machining are 4140 and 4340.

They have good strength and toughness, which can be further enhanced through quenching and tempering.

4140 is suitable for manufacturing bearings, gears, shafts, and mechanical components. 4340 has better hardness and strength than 4140. 4340 is typically used for manufacturing high-strength, high-load-bearing, and highly wear-resistant parts, such as aircraft engine components, automotive transmission shafts, and construction machinery parts.

Alloy Steel Subtypes

Ultimate tensile strengthYield strengthYoung’s modulus (modulus of elasticity)Elongation at breakCorrosion resistanceMagnetismWeldabilityApplication
Alloy Steel 4140355 – 370 MPa230 MPa208 – 216 GPa18 – 26 %Moderate to PoorSemi-MagneticModerateHeavy duty shafts Connecting rods High tensile boltsLearn More
Alloy Steel 4340690 – 1080 MPa470 – 630 MPa205 – 213 GPa15 – 22 %Moderate to PoorSemi-MagneticModerateHigh tensile applications General engineering parts Connecting rods & boltsLearn More

Alloy Steel CNC Machining Surface Finishes

Alloy Steel CNC Machining Gallery

Cost-saving Design Tips

Steel is one of the cheapest materials suitable for CNC machining. However, take care to avoid unnecessary machining costs. Below are some cost-saving design tips:

1.Material selection

Inexpensive though it may seem, it is necessary to select the best steel for your particular application. Utilizing high-strength alloy steel where moderate steel will certainly work increases costs for no included advantage.

2.Part setup

Designing a part to reduce the variety of machining setups can considerably reduce the cost of production. This is particularly true when machining low-cost materials as any cost savings on the material can be quickly removed by costly configurations.


Common alloys include 4140 and4340, known for their strength and toughness.

Yes, heat treatment can further enhance the mechanical properties of alloy steel parts.

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