×
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

Chromoly equivalent
3

Chromoly equivalent

Chromoly equivalent

(OP)
Hello, I am looking to duplicate a mountaineer's piton made out of forged chromoly steel - I'm assuming 4130 - with a machinable alternative that is of like strength and low cost. Any ideas? Thanks!

RE: Chromoly equivalent

guimba;
Do you know all of the design specifics related to this item? What is the strength level you need? Reverse engineering without all the necessary design information can be a problem.

RE: Chromoly equivalent

4130 is both machinable and low cost.

RE: Chromoly equivalent

(OP)
I forgot to mention that the material wants to have a RHC of at least 28, from a piton standard I uncovered.  This is needed so it can wedge in concrete or other hard materials.  It will be used as part of a hook & line kit to exert a pulling force; no loss of life or danger if it fails.  I have no strength requirement other than to duplicate the 4130.  Is it castable?  Would the casting be heat-treatable as would the machined part?  Thanks for the help.

RE: Chromoly equivalent

There's a reason it's forged 4130 or something similar.  That is a reasonably strong steel, good ductility, readily available in wire, bar, or forgings.  It certainly can be cast, and heat treated castings will be strong, but they will also be brittle.  If you plan on this part seeing impact loading, say from a hammer pounding it into a rock crevice, then casting will not be optimum.

RE: Chromoly equivalent

(OP)
What would be the correct material callout for the cast part?  Make from AISI 4130 PH alloy steel?  Would another alloy in the series be indicated?  Thanks.

RE: Chromoly equivalent

(OP)
Also, one of our suppliers offered to cast the part in ASTM A27 Grade 65-35 carbon steel.  Is this a suitable material?  Should I specify that it be heat-treated to RHC 28-32?  Thanks!

RE: Chromoly equivalent

Please don't use castings on mountaineering hardware!  Forgings that are properly annealed, trimmed, machined, stress relieved, heat-treated, and then x-rayed, are the proper way to go.  There are applicable standards to follow when producing hardware that will be used to support a human load, and for life-critical components.

RE: Chromoly equivalent

Why would you x-ray a forging?

rp

RE: Chromoly equivalent

If you were the guy hanging from a piton on a rock wall, wouldn't you feel better if the company that made it went to some effort to keep rejects out of the product stream?  Granted, were not talking about huge cross sections and the problems you see with those, but there is a human life depending on that little piece of steel.  It takes, what, a minute to x-ray a piton or carabiner sized piece?????  

RE: Chromoly equivalent

Obviously it would be in my best interest not to trust my life on defective equipment.  I'm just questioning the ability of the x-ray inspection to identify a defect in a forged piton.   

rp

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