8620 Steel vs 4140 Steel – What’s the Difference

8620 Steel vs 4140 Steel

When it comes to choosing between different types of steel, it can be a daunting task without the right knowledge and information. Two of the most popular types of steel that come up in conversations are 8620 and 4140 steel. Both are commonly used in various industries, such as automotive, aerospace, and machining. But what are the differences between these two types of steel? In this blog post, we will dive into the key characteristics of 8620 steel and 4140 steel to help you decide your needs.

Difference Between 8620 Steel and 4140 Steel


8620 steel and 4140 steel have different compositions. 8620 steel is a low nickel-chromium-molybdenum case-hardening steel, whereas 4140 steel has high chromium and molybdenum content. This means 4140 steel has better hardenability and toughness, while 8620 steel has better core strength and toughness.

Heat treatment:

Both 8620 steel and 4140 steel require heat treatment to achieve their desired properties. 8620 steel is typically carburized and quenched, while 4140 steel is quenched and tempered. The different heat treatments result in different properties for the two steels.


Due to their different properties, 8620 and 4140 steel are used in different applications. 8620 steel is often used for gears, crankshafts, and other machinery parts that require high toughness and fatigue resistance. 4140 steel is often used in applications that require high strength, such as bolts, nuts, and shafts.


4140 steel is known for its excellent machinability, while 8620 steel can be more difficult to machine due to its higher toughness. However, 8620 steel has better welding and forming properties than 4140 steel.


8620 and 4140 steel costs can vary depending on the application and supplier. Generally, 4140 steel is more expensive than 8620 steel due to its higher carbon content and alloying elements.


In summary, the main differences between 8620 steel and 4140 steel lie in their composition, heat treatment, applications, machinability, and cost. When deciding which type of steel to use, it is essential to consider each factor to ensure that you choose the most appropriate steel for your needs. Remember that there is no perfect type of steel for every application, so it is crucial to choose the one that best suits your specific requirements. With the information provided in this blog post, you are better equipped to decide which type of steel to use.

Minal Jogale

Minal Jogale

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