What Makes Case Hardening And Surface Hardening Different?

What Makes Case Hardening And Surface Hardening Different?

Date: March 16, 2018

Heat treatment is used to modify the properties of a material, especially in metallurgy or in industries that deal with the production and purification of metals. This is a type of industrial process that involves altering the chemical and physical properties of metal alloys.

There are four major types of heat treatment methods: annealing, tempering, hardening, and normaling. Hardening is popular among those who want to increase the hardness of the metal for strength and durability. Case hardening and surface hardening each have their benefits.

What is case hardening?

Case hardening is a simple approach that hardens the surface of a material by infusing elements into the metal. It forms a thin layer of hardened alloy called a case. This method is generally used on metal alloys that have a low carbon content. Carbon is infused with the metal at a depth specific per application. Case hardening helps to make sure the core of the metal remains untouched because the properties themselves have remained unchanged as well.

For industrial gearboxes, case hardening can protect many components by creating a stronger surface. This can prevent wear and tear from damaging your equipment too quickly.

The case hardening process

This process involves heating the metal, like steel, until it becomes red hot, then removing it from the hearth and plunging into cold liquid. This is called quenching the steel and it helps to make the surface more accessible to the element it will be infused with once cooled. The process is repeated until the steel has a hardened surface that surrounds an unchanged core. Case hardening can take place several times to increase the depth of the hardened metal.

What is surface hardening?

Surface hardening increases the hardness of the metal’s surface while keeping the core soft. Most experts agree that there are two methods of this heat treating technique, and each provides a much different approach.

Differential surface hardening brings only the surface of the metal to a red hot degree, while keeping the core at a lower temperature. Once the surface comes to the desired temperature, it gets quenched. The other surface hardening approach works by using an oxygen gas torch to increase the temperature of the surface.

Induction hardening is similar to flame hardening, but it uses electronically induced coils instead of an open flame. The coils create a magnetic field that induces an electrical current to run through the metal. The surface gets heated to the desired temperature before quickly getting quenched. This method of surface hardening can be used for smaller industrial gearbox components.

Differential metal structure surface hardening

Two common methods are used to infuse an element into the surface area of a metal alloy in this surface hardening technique. Carburizing places the metal alloy in a carbonaceous environment at a very high temperature for several hours. An increase in temperature will allow the carbon to be absorbed into the metal and slowly diffused onto the surface layer. Another approach is combining nitrogen and heat together. This diffuses nitrogen onto the metal’s surface at a lower temperature than carburizing the metal.

The biggest difference between surface and case hardening

The biggest difference between each process is that case hardening creates a thin layer on the surface. Surface hardening hardens the outer surface and keeps the core soft throughout the entire process. The method of heating the metal is different, but each process is followed by quenching the hot surface after reaching a desired temperature. If you aren’t sure which method to use for your industrial gearbox and its components, looking at the manual or speaking with a professional can help.

Professional industrial gearbox repair and maintenance

No matter what type of heat treatment your gearbox was given, if it breaks down, you will need experienced help. If you need high-quality industrial gearbox inspection, repair, or maintenance, contact the experts at Amarillo Gear Service in Amarillo, Texas today. We are a division of Amarillo Gear Company, which has been in continuous operation since 1917. You can call us at (806) 622-1273 or Contact Us by email to learn more about our Amarillo Gear™ and Marley™ gearbox repair services. We will be glad to tell you more about the Regions We Service and the quality workmanship we can bring to the repair or Renewal of your drive.

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