ThePipingMart Blog Metals 8740 Steel vs 4140 Steel – What’s the Difference

8740 Steel vs 4140 Steel – What’s the Difference

8740 Steel vs 4140 Steel

In the world of metallurgy, steel is a staple material used in a wide range of applications due to its unrivalled strength and durability. However, not all steel is created equal. Two common steel grades that are often compared are 8740 and 4140. These steels have distinct differences that make them suitable for different applications. If you’re wondering which one to choose, this post will discuss the strengths and weaknesses of each.

Difference Between 8740 Steel and 4140 Steel

Chemical Composition

The first difference between 8740 and 4140 steel is their chemical composition. Both are alloy steels but have different alloying elements. 8740 steel contains carbon, chromium, molybdenum, phosphorus, and silicon. These elements boost the steel’s strength and provide excellent toughness. In contrast, 4140 steel consists of carbon, chromium, molybdenum, manganese, and silicon. The manganese content improves the steel’s hardenability, while the molybdenum provides high strength and toughness.

Strength and Hardness

Regarding strength and hardness, both steels have unique properties that make them suitable for various applications. 8740 steel is incredibly tough and resilient with its high carbon content. It also has excellent shock resistance and fatigue strength, making it perfect for aircraft landing gears, drive shafts, and other high-stress components. On the other hand, 4140 steel is highly durable and has great wear resistance. It can also be heat-treated to enhance its hardness and tensile strength and used for axles, crankshafts, and gears.


Another factor to consider is machinability- how easy it is to work with the steel. In this aspect, 4140 Steel takes the win. It is easier to machine than 8740 steel and can be worked into intricate shapes and designs. 8740 steel has a lower machinability rating due to its toughness and resilience. It takes longer to drill or turn due to its hardness and powerful impact resistance.

Cost and Availability

Last but not least, the cost and availability of the steel is another key factor to consider. For smaller projects, the price difference between the two might be minimal. However, the cost difference can be significant for larger applications, and 4140 steel might be the best and most affordable option. Furthermore, the availability of both steels varies from region to region. So, it’s essential to check their availability before placing an order.


In conclusion, 8740 and 4140 steel are two exceptional alloy sheets with different properties and suitable for different applications. 8740 steel, with its toughness and shock resistance, is excellent for high-stress components like aircraft landing gears, while 4140 steel, with its wear resistance and machinability, is perfect for axles and gears. The choice ultimately comes down to what you’re using it for, your budget and the availability of the steel. Hopefully, this post has provided enough information to make an informed choice.

Related Post