×
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

cad plating 17-4 ph - Hardness effects
3

cad plating 17-4 ph - Hardness effects

cad plating 17-4 ph - Hardness effects

(OP)
Have: 17-4ph 1/4 dia. pins, Age hardened to HRC40 Min.
      Parts subsequently CAD plated type II, CLass2 IAW AMS-QQ-P-416. Hydrogen embrittlement relief carried out for a minimum of only 4 hrs IAW 3.4.1 of NAS1332 ILO 8hrs as spec'd by ...P416.  Parts were HRC40 min prior to Age harden.
As returned from plater, HRC now down around 38HRC, now below minimum. Would the hydrogen embrittlement relief cause this? (Carried out at
375+/- 25 deg F.  Any thoughts? along these lines - or others?)

RE: cad plating 17-4 ph - Hardness effects

2
Did you actually checked the pins prior to cad plating or you assume/hope the hardness was 40RC Min? I assume that this was the requirement in the drawing but I believe there was also a heat treatment requirements such as H1025. What was the heat treatment of the 17-4PH? Was it H1025 or H1075? if so then 375F for embrittlement relief has no effect. One more fact to take into account is that for a specified heat treatment such as H1015 the hardness can vary up to 10RC. This is why you will never see a hardness specified in MIL-HDBK-5 for precipitation hardening alloys such as 17-4PH or 15-5PH, etc., but only yield and tensile strength. Therefore, the min 40RC requirement has no meaning if a heat treatment is specified.

RE: cad plating 17-4 ph - Hardness effects

As israelkk noted, heating 17-4PH to 400 F for 4 hours will not reduce the strength if it was properly aged to the H900 condition (900 F, 40 HRC min according to ASTM A 564, etc.).  You will need to metallurgically evaluate the pins in order to determine the issue.

RE: cad plating 17-4 ph - Hardness effects

Are you measuring the same exact pins?  Statistical variation could explain your findings.  Are you measuring on a flat surface or concave surface and correcting the value?  How thick is the CAD plate?  If you were doing microhardness and converting I could see the CAD plate throwing your readings lower.  Remove the plating and recheck your hardness.

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