What are Alloy 4140 and Alloy 4130 Properties and Differences?


The production of good quality material is often achieved with techniques like Rapid prototyping. It includes processes that work on varying principles such as 3D printing, injection molding, CNC machining, etc. Steel is considered an ideal material because of its higher strength and durability, But its properties depend on the type of steel grade you choose. 4140 and 4130 are the most popular grades. In this article, we will discuss the properties and differences of both grades in detail.

Alloy 4140 denifition, properties and applications

Alloy steel mainly consists of major alloying elements, including manganese, molybdenum, and chromium. It is an excellent choice on an industrial scale because of its impact resistance, high fatigue strength, hardness, and abrasion.

The excellent properties of alloy 4140 make it best for rapid prototyping operations such as sheet metal fabrication and CNC machining. A few properties of alloy 4140 are discussed below:

1: Machinability

It is highly machinable and thus known for its good machinability. But, it is not good for welding, so fabrication is much more difficult. Therefore, heat treatments are applied to weld it. It can be welded in its stable state, which is the annealed state.

2: Corrosion-resistant

Steel alloy 4140 is highly corrosion-resistant. Thus, it is not affected by corrosion even in an open environment. However, it can be affected by rust.

3: Extreme hardness

It is much harder compared to normal steel because of the higher contents of chromium and carbon. Its tensile strength is 148000 PSI. Therefore, heavy loading cannot break it, making it more durable.

4: Ductility

It is known for its extreme flexibility, which means it is highly malleable. You can transform it into various shapes without damaging it. It can easily draw into different types of wires.

The excellent properties of alloy 4140 make it suitable for manufacturing various components or parts worldwide. It is used for the manufacturing of the following components.

  • Steel stub & Steel piston rod
  • Steel ejector
  • Drill collar
  • Steel coupling
  • Steel conveyor and roll
  • Steel collet & Slide
  • Nut & Milling spindle
  • Gear & Machinery components
  • Bolts & Crankshaft
  • Shaft etc.

Alloy 4130 denifition, properties and applications

Alloy 4130 is the main steel alloy consisting of alloying elements, molybdenum, and chromium. It is also referred to as Chromoly. The molybdenum and chromium percentages are 0.15-0.25% and 0.8-1.1%. It is much more brittle than mild steel and can be easily welded because of its low carbon content.
Here are some important properties of alloy 4130.

1: Elasticity

Alloy 4130 possesses high elasticity. This elasticity is because it has a high modulus of elasticity. It can return to its original position even if a high force is applied. Thus, it can easily bear a large amount of strain.

2: Tensile strength

The tensile strength of alloy 4130 is much higher. It shows a tensile strength of 97200 PSI. On the Rockwell hardness scale, its value is C20. Its higher tensile strength makes it a much more durable steel alloy.

3: Ductility

Alloy 4130 is a highly malleable steel alloy. You can draw various wires from it because of its high flexibility. It mostly shows high ductility in its annealed form.

4: Weldability

It can be easily welded because of the low contents of carbon. It makes it ideal in tube, coil, and sheet form because it can use to fabricate the parts of pipe works and aircraft for the oil and gas industry.

Alloy 4130 possesses extreme strength, hardness, and high weldability. These qualities are the reason it is widely used for the following purposes.

  • Aerospace & Motorsports
  • Hydraulics
  • Machine tools & Automotive
  • Commercial jets
  • Military crafts
  • Mills and cutters
  • Drill bits & taps
  • Resistance welding products
  • Rock crushing machinery

It also shows uses in the oil and gas industries in welded tubing. It is an ideal steel alloy for machine parts and fabricating car components.

Differences between Alloy 4140 and Alloy 4130

Some major differences between alloy 4140 and alloy 4130 are as follows:

1. Composition

Both steel alloys, i.e., 4140 and 4130, differ in their compositions. They have different percentages of alloying elements.
4140 contains 0.38-0.43% Carbon and 0.75- 1.00% Manganese. On the other hand, alloy 4130 has a composition of 0.40-0.60% Manganese and 0.28-0.33% Carbon.

2. Mechanical properties of normalized 4140 and 4130 steel alloys

Brand Brinell hardness Elongation Yield Strength Tensile Strength
Alloy 4140 302 17.70% 95000 psi 148000 psi
Alloy 4130 197 25.50% 63000 psi 97000 psi


3. Mechanical properties of annealed alloy 4140 and alloy 4130

Brand Brinell hardness Elongation Yield Strength Tensile Strength
Alloy 4140 197 25.70% 60500 psi 95000 psi
Alloy 4130 156 28.20% 52300 psi 81300 psi

4. Weldability

Alloy 4130 has higher weldability than alloy 4140. This weldability is why all 4130 is highly used fabrication because of more welding requirements. Their weldability also depends upon their heat treatment processes.

5. Material availability

Alloy 4140 is more easily available than alloy 4130 and can be found in the form of bars and plates. On the other hand, alloy 4130 is present in tubes and sheets.

6. Machinability

The machinability of both steel alloys differs greatly. Alloy 4130 has high machinability as compared to alloy 4140. The relative machinability of alloy 4140 is 65%, while the machinability of 4130 is 70%.


The alloy 4140 and alloy 4130 are both popular steel alloys in engineering. But choosing the right steel alloy for your specific purpose is necessary. In this case, you must have a complete idea about both steel alloys. Without knowing the properties, applications, and comparisons between two alloys, you will be unable to choose the right one.
The above-discussed detailed information and comparison of both alloys can help you to select the right manufacturing company and steel alloy for your business. It will magically help you to bring your business to the next level. Contact Worthy Hardware for the best solution for your projects and find more than your desired expectations.