×
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

casting alloy for nitriding

casting alloy for nitriding

casting alloy for nitriding

(OP)
We are looking to change our existing alloys for investment casting from 431 stainless steel to 4130 or 17-4 ph.  We then saltbath nitride the parts.  We want to reach a Rc of around 30-34 Rc to prevent the parts to become too brittle but keep a good wear characteristic.

Which alloy would be the best choice and why?

thanks

p

RE: casting alloy for nitriding

Either of your materials will SBN with ease.
SBN or salt bath carbo-nitriding of 17/4 will give you one of the best easily wear surfaces there is. If you use a process like QPQ (Quench Polish Quench) it will enhance most of the properties of either over just QP (Quench Polish).

I would go with the 17/4 as it has been my work horse as far as wearing and galling. I have a sleeve and barrel made from 17/4 and Nitronic 60 that have run over thirty year in split case horizontal injection pump for a waste injection well. I haven't used much SBN 4130. We used a lot of 4130/4140 parts that are gas nitrided in some very severe services with good results.
A word of caution 17/4 doesn't gas nitride very well.

If you could describe your application it will help someone give you a better answer.
It would be nice to know what you are running against.

Here is a pretty good paper on the SBN process.   
http://www.burlingtoneng.com/wear_resistance.html

RE: casting alloy for nitriding

Forgot to add neither material will be brittle as this process is surface phenomena. The core is unaffected if you temper the 4130 at least at 1000F and the 17/4 at H1150.  

RE: casting alloy for nitriding

As unclesyd mentioned, both can be surface hardened using salt bath nitriding.  4130/4140 is frequently nitrided as is 17-4 PH, so it probably comes down to what strength do you want and how much will it cost.  30-34 HRC will be no problem for either alloy.  17-4PH will cost several times what 4130 does.

RE: casting alloy for nitriding

and how much corrosion resistance you are looking for.  the 17-4 will be similar to your 431, the other is a steel.

If you sue the 17-4 you need to integrate the SBN and the aging treatment.  You don't want to use 17-4 that has not been properly heat treated and aged.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

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