Meaning of Case Hardened on Metal

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Steel is an incredible material that can be transformed into various properties by adding different elements and altering its heating and cooling process. Steel can be bent easily, while others are too brittle and can shatter. Some rust, while others don’t. Due to its versatility, steel is used in a wide range of applications, from surgical tools to massive metal frames of skyscrapers.

Case hardening involves creating two different types of steel at different points in time. During production, a relatively soft steel is preferred for easy bending and machining. However, for a lock’s shank, a soft steel is not ideal as it can be quickly cut with a metal saw. After the piece is formed, it is hardened to make it challenging to cut. The process of case hardening involves diffusing carbon and/or nitrogen into the outer layer of the steel at high temperatures. The carbon combines with the steel, making it almost glass-like in hardness, while the core remains soft. This results in a piece of metal that cannot be cut with a saw but will not shatter.

Learn More About Case Hardening

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1. What is “Case Hardening”?

Case Hardening is a process used to increase the hardness and durability of certain metals. It involves adding a thin layer of a hard material to the surface of the metal, while leaving the interior relatively soft and ductile. This process can be used on a variety of metals, including steel, iron, and copper.

2. How is “Case Hardening” done?

There are several methods for Case Hardening, but the most common is carburizing. This involves heating the metal in a carbon-rich environment, which causes carbon atoms to diffuse into the surface of the metal. The carbon reacts with the metal to form a layer of hard, wear-resistant material called “case.” This layer typically ranges from 0.1 to 2 millimeters thick.

3. What are the benefits of “Case Hardening”?

Case Hardening provides several benefits. It increases the wear resistance of the metal, making it more durable and longer lasting. It also increases the surface hardness of the metal, which can be useful in applications where the metal is subjected to high stress or impact. Additionally, it can improve the corrosion resistance of the metal.

4. What types of metals can be “Case Hardened”?

Case Hardening can be used on a variety of metals, including steel, iron, and copper. It is most commonly used on low-carbon steels, which are relatively soft and ductile, but can be made much harder and more wear-resistant through Case Hardening.

5. What are some common applications of “Case Hardened” metals?

Case Hardened metals are commonly used in applications where wear resistance and durability are important. They are often used in gears, bearings, shafts, and other components that are subjected to high stress or impact. They are also used in tools, such as drills and cutting blades, where hardness and wear resistance are critical to performance.

6. Is “Case Hardening” reversible?

No, once a metal has been Case Hardened, the process cannot be reversed. The layer of hard material that has been added to the surface of the metal is permanent and cannot be removed.

7. Can “Case Hardening” be done at home?

While it is possible to Case Harden metal at home using improvised methods, it is generally not recommended. The process requires precise control of temperature, carbon content, and other variables, which can be difficult to achieve without specialized equipment. Additionally, improper Case Hardening can result in brittle, unreliable components that are more likely to fail under stress. It is generally best to leave Case Hardening to professionals with the appropriate equipment and expertise.

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