×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Carbon atmospheres
2

Carbon atmospheres

Carbon atmospheres

(OP)
Simple question; I am wondering in which atmosphere steel, at critical temperature more easily absorbs carbon. Carbon monoxide, or carbon dioxide? Thanks.

RE: Carbon atmospheres

Are you interested in carburizing, or neutral hardening (i.e. avoiding decarb)? What specific type of atmosphere do you have in mind? Most heat treating atmospheres for steel are a mix of gases, such as CO,N,CO2 and H2. Carbon potential of the atmosphere , carbon content of the steel and temperture are some of the factors that determine how quickly steel absorbs carbon (or loses it).

RE: Carbon atmospheres

(OP)
I am designing a simple oven, and want to be able to have a neutral, and, or a slightly carburizing atmospheres without a complicated system.

RE: Carbon atmospheres

(OP)
Can a 100% CO2 atmosphere be used as a neutral hardening gas for medium carbon steels?

RE: Carbon atmospheres

As swall has mentioned, a standard gas carburizing atmosphere relies on partial pressures between CO/CO2, H2/H20, a carrier gas and methane that can provide a source for carbon potential.

In your case to keep it simple and safe, I would use an Argon gas purge to provide for a neutral or inert atmosphere for heating and cooling.

RE: Carbon atmospheres

A straight CO2 atmosphere will not prevent decarb. For a simple atmosphere, I would suggest nitrogen, with some natural gas metered in. The major gas suppliers sell equipment to produce this type of atmosphere.

RE: Carbon atmospheres

(OP)
Thanks for the replies.
The spec for normalizing 4340 mod, requires a long cool down time in the oven. I need as little decarb as possible, without producing a *potentially* dangerous atmosphere. Also I might want to carburize a wee bit during hardening. Thanks again.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources