The Basics of Carburizing in Gastonia, NC

At J.F. Heat Treating Inc., we understand that, while you rely on metal parts and components for your tools and equipment and recognize the importance of their being in good shape, making sense of how we get them working better may be a little more difficult. Through a variety of heat treatment options, our goal is to make sure your equipment is functioning at its highest level and your components and parts are sturdy and reliable.

One of the key processes we use when working with metals is the process of carburizing. Understanding the process of carburizing in Gastonia, NC will allow you to better comprehend one of the key processes used by heat treatment professionals as they work with metal parts and components. Carburizing is also known as case hardening, after the formation of a strong, wear-resistant outer casing layer that is carburizing’s main product. This outer casing layer surrounds a strong, solid core.

Carburizing is typically only employed on low-carbon steels, which are classified as steels with less than 0.25 percent carbon. The steels may or may not be alloyed, as well. (Nickel, chromium, manganese and molybdenum are often introduced as alloying elements.) Carburizing works more effectively on low-carbon steels than other treatment processes, such as tempering or quenching.

The process of carburization

The process works by way of the introduction of carbon, by heating a metal in contact with that carbon to a point above the transformation range, into a solid ferrous alloy. How far the carbon is able to penetrate the metal depends on several factors, not least of which is the type of carburizing agent itself. Other factors include the temperature at which the heating takes place, as well as the length of time for which the metal is heated. By way of example, a four-hour, 1700-degrees Fahrenheit heating process can result in a depth of carburization of about 0.03 to 0.05 inches. This doesn’t sound like much, but the end result is a hard outer layer that requires some amount of hardening and tempering to get just right.

Different agents, different results

A carburizing agent can be a solid, a liquid or a gas, so long as the agent is high in carbon content. Hardwood charcoal is commonly used as a solid carburizing agent, while liquid carburization comes from the use of sodium cyanide and barium chloride, which yield carbon monoxide. In gas carburizing, carbon monoxide is produced by the use of either natural gas or propane.

Gas carburizing compares favorably to carbonitriding—which involves the addition of ammonia into the atmosphere—but allows for greater case depth. For parts and components that will be subjected to considerable wear, this makes gas carburizing especially appealing. And while gas and liquid carburizing tend to be much faster than using a solid agent, they’re less effective methods if you need to carburize a particularly large part or component.

If you work with a lot of metal parts and components, you know the value of keeping those components working and looking their best. For any heat treatment needs you may have, including carburizing in Gastonia, NC, contact J.F. Heat Treating Inc.

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