8620 Steel vs 4620 Steel – What’s the Difference

8620 Steel vs 4620 Steel

Steel is a versatile material used extensively in many industries for its durability, strength and resistance to corrosion. However, it can be challenging to choose the right type of steel for a particular application, especially when deciding between different steel grades. In this post, we will explore two types of steel – 8620 steel and 4620 steel. We will look at the properties, uses and differences between these two types of steel to help you choose the best steel for your project.

Difference Between 8620 Steel and 4620 Steel

Composition and Properties

8620 steel is a low alloy with nickel, chromium, and molybdenum. These elements give it excellent strength, toughness, and hardenability. It is commonly used in engineering applications, including gears and axles. Interestingly, this steel can be heat-treated to improve its hardness and strength.

In contrast, 4620 steel is also a low alloy steel that contains chromium and molybdenum, but it has a higher nickel content than 8620 steel. This steel has toughness and ductility, making it ideal for high-strength and shock-resistance applications. It is commonly used to manufacture aircraft, automotive parts, and heavy-duty machinery.


Given the properties of both 8620 and 4620 steel, they have found extensive use in different industries. 8620 steel is commonly used in the aerospace, automotive, and military industries. For example, it manufactures gears, shafts, and axles in cars and trucks. As for 4620 steel, it is ideal for use in manufacturing heavy equipment, axles, gears and crankshafts for aircraft and diesel engines.

Welding Process

The welding process for both 8620 and 4620 steel is similar. However, welding 8620 steel requires a preheat, which is not as necessary in welding 4620 steel. Preheating will ensure that your steel undergoes a more comprehensive annealing process post-welding. On the other hand, the welding process for 4620 steel ensures high strength and resistance to shock and deformation.


Both 8620 and 4620 steel are highly machinable. The heat treatment of 8620 steel makes it a bit harder, which can pose a challenge in cutting and shaping. However, you can quickly obtain your desired shape with the appropriate machining tools. 4620 steel has excellent machining properties, making it widely used in manufacturing.


Both steel types can be slightly expensive, and the premium quality forms can be more expensive to purchase. However, due to the different properties, the cost-effectiveness of each type of steel may differ depending on usage. 8620 steel is lower in cost than 4620 steel, which is more common in the aerospace and military industries, where performance exceeds cost.


Choosing the right type of steel is crucial, and the properties of 8620 and 4620 steel make them ideal for various applications. The difference in nickel content, applications, cost, and machining properties means that each steel type may be more suitable for specific projects. We hope this post has helped you understand the properties and applications of 8620 and 4620 steel, and you can now make an informed decision when choosing the right steel for your project.

Minal Jogale

Minal Jogale

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