Contact US

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!

*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

Dear experts, Please explain why s

Dear experts, Please explain why s

Dear experts, Please explain why s

Dear experts,
Please explain why stainless steels only solution annealed?

RE: Dear experts, Please explain why s

As opposed to what?
You in general don't stress relieve SS grades because nearly all of the alloys will form detrimental phases in the microstructure at temps that are needed for stress relief. That leaves your only option as going back to full anneal.
It greatly depends in the type of SS.
Austenitic (200 and 300 alloys) have no hardening mechanism other than cold work. Most of these alloys can be used from cryogenic temps to very high temps. But they do not like exposure in 1200-1600F range (more or less depending on the alloy). The exception to this is the stabilized alloys (321/347) where the C is tied up in the carbides deliberately.
The 400 series alloys come in two varieties, Ferritic and Martensitic. These alloys all have DBTT to worry about at low temps.
The ferritic grades have very low C and in general are only usable up to 600F and are not hardenable by HT.
The martensitic alloys are hardened by Q&T but most have a 'temper embrittlement' range to watch for.
The duplex grades also do not harden by HT and are only usable up to 600F. And these also have DBTT issues.
The other group are PH grades. Each of these needs to be looked at separately because of the various HT temps.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Dear experts, Please explain why s

Thanks, Ed... bunch of good info.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates


RE: Dear experts, Please explain why s

Good summary Ed!

One may take "stainless steels only solution annealed" a rule of thumb, and it may apply to some general stainless. But it is exactly not right. as Ed pointed out, PH grades normally must anneal/age after solution to precipitate phase to strengthen material. for example, 17-4 (630) condition H1150 is obtained by anneal at a temperature of 1150F. Stabilized grades 321/347 needs to anneal at intermediate temp to have Nd/Ti tied with carbon to protect Cr.

Sometimes for cold worked SS, one could do a sub-critical anneal, or stress relief anneal to control grain growth and soften/stabilize the material. but caution must be taken to prevent sensitization and/or undesired phase precipitation. Low carbon "L" grades may not have sensitization issue, but even lower temp stress relief anneal could boost hardness even for 316L.

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close