ThePipingMart Blog Metals S7 Tool Steel vs Carpenter 158 – What’s the Difference

S7 Tool Steel vs Carpenter 158 – What’s the Difference

S7 Tool Steel vs Carpenter 158

It is a daunting task to pick the right tool steel for your projects. Two popular tool sheets of steel that often come up in discussions are S7 Tool Steel and Carpenter 158. But which one is better? In this blog post, we’ll look at each steel’s properties, uses, and advantages to help you make an informed decision.

What is S7 Tool Steel?

This steel is known for its toughness and shock resistance, making it a popular choice for tools that experience high impact and stress. S7 Tool Steel has a relatively high carbon content, which gives it great wear resistance and edge retention. It also has a high chromium content, which makes it resistant to corrosion. S7 Tool Steel is commonly used for chisels, hammers, punches, and hard work dies.

What is Carpenter 158?

Carpenter 158, also known as C158, is a high-speed tool steel often used for cutting tools requiring high wear resistance. It has a high molybdenum content, which makes it resistant to wear and tear. C158 is also known for its excellent heat resistance, which makes it ideal for making tools exposed to high temperatures, such as blades, cutters, and dies.

Difference Between S7 Tool Steel and Carpenter 158


One of the biggest advantages of S7 Tool Steel is its ability to maintain its shape even after repeated usage. This steel can be hardened up to 60 HRC without becoming brittle, making it extremely durable and long-lasting. Another advantage is its ability to be machined easily, making it ideal for complex tool shapes.

One of the advantages of Carpenter 158 is that it has a high melting point, meaning that it can be hardened to a higher level without losing shape. C158 also has excellent machinability, which makes it ideal for tool-making processes that require a lot of precision.


Regarding cost, S7 Tool Steel is generally less expensive than Carpenter 158. However, the cost of the steel is just one factor to consider when deciding which tool steel to use. Other factors include:

  • The tool’s intended use.
  • The required level of hardness.
  • The complexity of the tool shape.


S7 tool steel and Carpenter 158 are high-carbon steels commonly used for various applications. However, they have different ideal uses. S7 tool steel is best suited for hot die stamping and forging applications, while Carpenter 158 is better suited for cold working applications.

Chemical Composition

S7 tool steel contains carbon, manganese, silicon, chromium, molybdenum, and vanadium. Carpenter 158 contains carbon, manganese, chromium, nickel, and cobalt. The different chemical compositions of these two steels give them different properties that make them more or less suitable for different applications.


S7 tool steel has a hardness of 48-52 HRC, while Carpenter 158 has a hardness of 60-62 HRC. The higher hardness of Carpenter 158 makes it more suitable for use in applications where wear resistance is important, such as cutting tools and dies. However, the higher hardness makes Carpenter 158 more difficult to machine than S7 tool steel.


S7 tool steel is widely available from a variety of manufacturers. Carpenter 158 is also widely available but may be difficult to find in some areas.


In conclusion, choosing the right tool steel for your tools is essential to ensuring their longevity and performance. Both S7 Tool Steel and Carpenter 158 have unique advantages and properties that make them suitable for certain applications. Overall, S7 Tool Steel is more suitable for tools that require high impact resistance and toughness, while Carpenter 158 is ideal for cutting tools that require high wear resistance at high temperatures. Ultimately, the choice between the two will depend on the specific requirements of your project.

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