We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Carburizing?

By Rolando Braza
Updated May 17, 2024
Our promise to you
About Mechanics is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At About Mechanics, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Carburizing is a metal treatment process that adds carbon to the surface of metal that has a low carbon content to increase the hardness of the metal. The metal is heated at an elevated temperature in an atmosphere rich with carbon. Heat will cause carbon atoms to diffuse into the metal surface. The process is done below the melting point of the metal being carburized. There are five carburizing methods — pack, gas, liquid bath, vacuum, and plasma.

Pack carburizing uses a furnace to heat the metal parts to be carburized that are packed inside a container with a sufficient amount of carbon powder. The heating process will last for 12 to 72 hours at a high temperature. This method is noted to be slow compared to the other methods and has heating inefficiencies because of the difficulty in maintaining an even temperature.

Gas carburizing follows the same procedure applied in pack carburizing. It, however, feeds carbon monoxide (CO) to the furnace to improve diffusion, which is not done in the pack method. The process has safety issues because CO is a poisoning gas that is odorless and colorless and could be inhaled by persons working inside the plant. The gas method is preferred in carburizing large volumes of metal.

In the liquid bath method, the metal parts are submerged in molten salt with abundant carbon. Cyanide (CN), which is a deadly poison, was previously used as the main component in the liquid bath. It was replaced by nontoxic bath components that can achieve the same carburization results as cyanide.

The vacuum method requires a heating environment that is free from oxygen and carburizes metal at low pressures. The method uses a furnace that has a complex structure and a single component to create a carbon-rich environment — methane (CH4). The oxygen-free environment allows the temperature to rise significantly, thus increasing the solubility of carbon and the rate of diffusion. No surface oxidation results from the process.

The plasma method utilizes a vacuum furnace to heat the metal. Once the metal attains a temperature suitable for processing, a rare gas containing hydrocarbon gases like CH4 is supplied to the furnace. High DC voltage is introduced between the metal and the furnace to generate a glow discharge that will cause the gas ion and the DC plasma to have an electrochemical reaction to accomplish carburization.

The choice of carburizing method must be guided by social and economic considerations. The method must be environmentally friendly and should not cause harm to the health of the workers and the community. It should also be cost-effective.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.