×
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

Cast Iron for heat treat fixture?

Cast Iron for heat treat fixture?

Cast Iron for heat treat fixture?

(OP)
I am considering making support for large gear during carburize cycle. Fixture is to be re-usable also. We normally used low carbon steel with decent success.

My question is whether there is any benefit to using cast iron instead, either by cost savings or durability.

Cylce will be 1700 F for approx 10 hours.
Support Ring will be 18.5" OD, 15" ID, 1.5" thick
Part weighs about 88 lbs.

Thanks

RE: Cast Iron for heat treat fixture?

I have no experience with carburizing, but in standard heat treatments cast iron has the tendancy to "grow" when being subjected to temperature cycles. A bit like multiple layerd wood plates that have become wet. Moreover it will have no strength at those temperatures.

Depending on how many times you want to use the fixture, I would look at heat resistant steels like 25Cr-9Ni. They are much more expensive, but they will stand significantly longer. they will also have some remaining strength at the temperature you mentioned. The nickel is necessary if you have high temperature gradients. The higher the gradient, the higher the Ni-content, going up to 25Cr-20Ni or even the Incoloy 800 series in case of water quenching.  

"There are easier ways of earning a living than in the casting industry. But few are as exiting"
After Prof. John Campbell

Gieter

RE: Cast Iron for heat treat fixture?

Gieter, I like your signature and my experience also is the same.

Coming back to cast iron fixtures,never heard of them being used,though chromium containing cast irons are used as furnace furniture in lower temperature zones.

At carburizing temperatures of 850C and above and prolonged exposure to high temperature may cause failure.  

The current practice of using steel fabrication is economical and simple. Distortion may be an issue. Many heat treaters in India use steel fabrications .

I have not failed. I've just found 10,000 ways that won't work." — Thomas Edison
_____________________________________
 

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