4140 vs 4130 Steel Selection Guide: Differences and Applications

4140 vs 4130 steel comparison

4140 and 4130 steel constitute two of the commonly used steel alloys in metal machining. Both steel variants are high-strength, low-alloy steels with excellent toughness and wear resistance. However, they differ in composition, properties, and applications.

Therefore, this article examines the differences between the 4140 and 4130 steel. It will also highlight their properties, applications, and crucial considerations when selecting the suitable steel grade. Let’s get right into it.

What is 4140 Alloy Steel?

4140 steel is a versatile, low alloy with chromium, phosphorus, sulfur, molybdenum, and manganese. Its relatively high carbon content enables hardenability and heat treatment to achieve a wide range of strength levels. Aside from this, 4140 steel offers excellent toughness, wear resistance, and fatigue strength, making it a popular choice for applications that require high-performance materials. This includes axles, shafts, gears, and hydraulic parts.

4140 steel material

4140 Steel Properties

4140 steel applies in various CNC steel machining applications and sheet metal fabrication, owing to the elements that combine to provide its unique qualities. Below are some key 4140 steel properties:

High Tensile and Fatigue Strength

4140 steel has high tensile and fatigue strength, making it suitable for high-stress applications such as crankshafts, gears, and axles.

Excellent Hardness and Toughness

4140 steel is heat treatable to achieve high hardness levels of up to 58 HRC, making it ideal for various applications. Further, 4140 steel exhibits good toughness and impact resistance, which enables it to withstand high loads without breaking or cracking.

Good Corrosion Resistance

4140 steel exhibits good resistance to corrosion agents, particularly when compared to other alloy steels. This makes it a suitable material choice for components often exposed to harsh environments. However, keep in mind that 4140 is not as corrosion-resistant as stainless steel.


4140 steel is relatively easy to machine, especially in the annealed condition. However, it gets challenging for the machine when it becomes hardened.

What is 4130 Alloy Steel?

4130 steel is also a low-alloy steel. This steel variant contains a relatively lower carbon content alongside other elements such as chromium, sulfur, silicon, molybdenum, manganese, and phosphorus. Combining these elements gives 4130 unique steel properties, including its high strength and toughness and excellent resistance to fatigue and corrosion. Hence, it is used in manufacturing various aerospace and other high-stress components.

4140 vs 4130 steel material

4130 Steel Properties

4130 steel is applicable in various manufacturing operations due to its characteristics. Check the main 4130 steel properties below:

Hardness and Tensile Strength

Like 4140 steel, 4130 steel also offers excellent hardness and tensile strength, making it suitable for high-stress applications. 4130 steel has a higher strength-to-weight ratio than mild steel. Thus, this makes it ideal for manufacturing projects where weight is crucial.


4130 steel has high elasticity with a yield strength of up to 460 MPa. This means the material can withstand a considerably high strain and return to its original shape or conformation.


4130 steel has excellent ductility, particularly in its annealed state. Thus, this makes it easy to draw the steel variant into wires.

High Corrosion and Temperature Resistance

4130 steel also has superior resistance to corrosive elements and can withstand high temperatures without losing shape or integrity.

Differences Between 4130 and 4140 Steel

Steel alloys are available in different grades, each with unique properties and characteristics that make them suitable for specific applications. Two such grades of steel that are commonly compared are 4140 steel and 4130 steel.

milling 4130 steel part

These steel grades are low-alloy steels commonly used in various industries due to their high strength and toughness. However, there are some critical differences between these two types of steel. Let’s examine the differences below:

1. Composition

Like 1018 vs. 4140 steel, the primary difference between 4140 steel and 4130 steel is their chemical composition. Check the chemical composition of both steel grades below:
The chemical composition of 4140 steel is as follows:

  • Carbon: 0.38%-0.43%
  • Chromium: 0.8%-1.1%
  • Manganese: 0.75%-1.0%
  • Phosphorus: 0.035% (max)
  • Sulfur: 0.040% (max)
  • Silicon: 0.15%-0.35%
  • Molybdenum: 0.15%-0.25%

On the other hand, the chemical composition of 4130 steel includes the following:

  • Carbon: 0.28%-0.33%
  • Chromium: 0.8%-1.1%
  • Manganese: 0.40%-0.60%
  • Phosphorus: 0.035% (max)
  • Sulfur: 0.040% (max)
  • Silicon: 0.15%-0.35%
  • Molybdenum: 0.15%-0.25%

As you can see from the chemical composition highlighted above, 4140 steel contains more carbon and manganese than 4130 steel. Even so, both steel materials get alloyed with similar amounts of chromium sulfur, silicon, and molybdenum, contributing to their strength and corrosion resistance.

2. Heat Treatment

Both 4140 and 4130 steel can undergo heat treatment of steel to improve their properties, but they require different heat treatment processes to achieve desired properties. 4140 steel gets quenched and tempered to achieve high strength and toughness.

During hardening, the 4140 steel reaches a temperature of 1600°F to 1650°F before quenching it in oil or water to achieve a Rockwell hardness of 40-45 HRC. After hardening, the steel gets tempered at a temperature of 500°F-600°F to increase its toughness while maintaining its hardness.

Conversely, 4130 steel typically gets normalized and tempered to achieve similar properties. During normalizing, the 4130 steel gets heated to a temperature around 1600°F to 1700°F before cooling in air. This helps improve its strength and toughness.

machined 4140 steel components

3. Mechanical Properties

The mechanical properties of 4140 and 4130 steel vary depending on their heat treatment and intended application. Take a look at the variations in mechanical properties between these steel grades below:

3.1 Strength and Toughness

4140 steel has a higher tensile strength and yield strength than 4130 steel, making it suitable for high-stress components. The tensile strength of 4140 steel ranges from 655 to 979 MPa, while the yield strength is around 415 MPa. The hardness of 4140 steel ranges from 28 to 32 HRC when hardened and tempered. But it has a lower hardness of approximately 17 HRC when annealed.

4130 steel, on the other hand, has a lower tensile strength and yield strength than 4140 steel but a higher ductility and toughness. The tensile strength of 4130 steel ranges from 560-725 MPa, while the yield strength stands at around 460 MPa. The hardness of 4130 steel ranges from 15 to 23 HRC.

3.2 Machinability

4130 steel is easier to machine than 4140 steel due to its lower carbon content. Experts often use various conventional methods, such as drilling, milling, and turning to machine 4130 steel without the risk of overheating or work hardening. 4140 steel, on the other hand, requires more cautious machining procedures to avoid cracking.

3.3 Weldability

One of the most significant advantages of 4130 steel is its weldability. It steel is more weldable than 4140 steel due to its lower carbon content. 4130 is suitable for welding using any standard method, such as gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW).

Meanwhile, 4140 steel requires preheating and various post-welding treatments to ensure that the welds on the steel are strong, durable, and free from defects.

4. Usage

Both 4140 and 4130 steel commonly apply in various industries for many purposes. However, 4140 steel is often preferred in applications requiring more extreme conditions or higher stress levels because of its slightly higher strength and durability than 4130 steel.

4130 vs. 4140 Steel: How to Choose the Right One?

Both 4140 and 4130 steel offer excellent strength and toughness but differ in their intrinsic properties. Therefore, you must understand both variants’ characteristics to choose the suitable steel material for your project, mainly based on the 4140 vs 4130 steel comparison. Here are some tips to guide you in choosing rightly between them:

1. Compare the Chemical Compositions of Both Steel

The chemical compositions of 4140 and 4130 steel differ in their amounts of carbon, manganese, chromium, silicon, sulfur, and molybdenum. Compare the chemical compositions of both steel alloys to determine which is better suited to meet the requirements of your application.

2. Assess the Mechanical Properties of Both Steel Grades

If your application requires high strength and hardness, 4140 steel may be the better choice. Its higher carbon and manganese content and ability to get quenched and tempered make it ideal for applications that involve high-stress parts.

Likewise, if your application requires lower strength and higher ductility, 4130 steel is a better choice. So, compare both steels’ tensile strength, yield strength, and hardness to determine which is better suited for your specific application.

CNC turned 4130 steel part

3. Determine the Machinability Requirements

If your application requires good machinability, 4130 steel makes an excellent choice. This is because its lesser shear stress strength implies faster chip disposal and lower cutting forces to machine into intricate shapes.

However, if your application requires high-strength components that are difficult to machine, you should go for 4140 steel. 4140 steel requires slower chip disposal and greater forces, making it more tasking to a machine. Also, you may need to check the suitability of your steel material for laser metal engraving before choosing.

4. Confirm the Heat Treatment Requirements

Both 4140 and 4130 steel can be subjected to heat treatment to achieve their desired properties, but they require different heat treatment processes. Thus, if your application requires a specific heat treatment process, this may influence your choice of steel.

For this reason, you must determine the heat treatment requirements of your application and compare them with the heat treatment capabilities of both steel grades before choosing.

5. Consider the Cost

The cost of 4130 and 4140 steel can vary depending on several factors. These include the supplier, the amount of steel required, the exact grade of steel, and the specific requirements of your application.

So, compare the costs of both sheets of steel to determine which offers the best value for your specific application. Generally, 4140 steel is slightly more expensive than 4130 steel due to its higher strength and hardness.

Applications of 4140 and 4130 Steel

Due to their properties, 4140 and 4130 steel are used in various industrial applications. Check them below:

plated 4140 steel part

1. Automotive Industry

4140 steel applies in the automotive industry for the manufacture of critical components such as connecting rods, crankshafts, and gears. Further, 4130 steel applies in the fabrication of racing car chassis, roll cages, and suspension components due to its high strength and fatigue resistance.

2. Construction Industry

Construction industries also utilize 4140 steel for buildings and bridge components that require high strength and durability.

3. Aerospace Industry

Both 4140 and 4130 steel apply in the aerospace industry to manufacture aircraft parts, such as landing gear components, wings, aircraft wings, engine parts, and other structural parts.

4. Structural Tubing

4130 steel applies in manufacturing bicycle frames, motorcycle frames, sports equipment, and other structural tubing applications due to its high strength-to-weight ratio and good weldability.

WayKen Offers Quality 4140 and 4130 Steel Machining Services

Steel machining is perhaps one of the most engaged machining processes in several industries today. Lots of industries apply different steel grades for various manufacturing purposes. Nevertheless, some people find it tasking to settle on steel grade for a project due to their conflicting properties.

At WayKen, you can get the best professionals to carefully handle all stages of your machining steel projects. Additionally, our metal machining services comprise quality surface treatments to give your machined steel parts the best finish. For more information, contact our support service today, and you will get a free quote soon.


4140 and 4130 steel are low alloy steel grades with excellent strength, toughness, and corrosion resistance. As a result, they still apply across various industries today for many manufacturing purposes. While 4140 and 4130 share some similarities, there are also some significant differences between these two types of steel. Understanding the characteristics and differences between these steel grades remains the best step to selecting the correct steel for your manufacturing project.


Which type of steel is better, 4140 or 4130 steel?

In terms of which one is better, it depends on the specific application and the requirements of that application. Ultimately, consulting with a materials engineer or a part manufacturer is essential to determine the best type of steel for a particular application.

Will 4140 steel rust?

4140 steel, which includes nickel, chromium, and molybdenum, increases passivation and, as a result, enhances corrosion resistance. Thus, this steel remains suitable for manufacturing parts subjected to harsh corrosive conditions.

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