×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Practicality of solution annealing heat treatment of Stainless steels?

Practicality of solution annealing heat treatment of Stainless steels?

Practicality of solution annealing heat treatment of Stainless steels?

(OP)
It is specified to do solution annealing heat treatment after welding of stainless steels & other nickel/chrome alloys. Often this is not practical if welding is done in the field (eg piping runs). This requirement is then waived?

What guidelines are available concerning the above?
When must it be done? or can be waived? What are the consequences?, benefits. What precautions or procedures may be used if it is not carried out?

Naren
e-mail: naren.sukaih@sapref.com


Naren Sukaih
naren.sukaih@sapref.com

RE: Practicality of solution annealing heat treatment of Stainless steels?

Stainless steels depend on chromium for their basic corrosion protection.  When welding, the chromium can become tied up with carbon and lose some of this protective ability.  One way around this is to use low-carbon stainless steels such as 304L or to use specially stabilized ones such as 321 or 347.

RE: Practicality of solution annealing heat treatment of Stainless steels?

In general, austenitic stainless steels do not require any heat treatment. For most applications, SS grade is selected so as not to warrant any heat treatment subsequent to welding. A good guideline is provided by davem&p above. If u wish to get further clarificatins/answers  me know.

RE: Practicality of solution annealing heat treatment of Stainless steels?

Dear All,
Do we need solution annealing for duplex steel, UNS S31803?
The thickness of my plate is 12.7mm. Please advise. Thank you.

Regards,
Lee
hockchong.lee@akerkvaerner.com

RE: Practicality of solution annealing heat treatment of Stainless steels?

Solution treating of stainless steels is primarily a base materials specification requirement - to be performed by the stainless steel product (tube, plate, forging, etc) manufacturer. It is not normally required of a fabricator of equipment/components made from stainless steel unless mandated by the Engineer/Designer or Customer.

RE: Practicality of solution annealing heat treatment of Stainless steels?

We've done some solution heat treatment of austentic stainless in the field and on some quite thickn sections. It's not for the faint hearted - because of the low thermal conductivity heating rates need to be quite slow in order to avoid inducing through wall stresses. Similarly HT of branch geometries is quite complex.

As Stanweld points out it is not usually a requirement and would normally only be specified for some particular reason. Ours was removal of residual stresses.  

RE: Practicality of solution annealing heat treatment of Stainless steels?

Sometimes our direct resistance heating is non uniform when solution annealing 304 and 316 stainless, I understand the set point temperature is 1900 - 2000 F.  Is their a maximum temperature that should not be exceeded?  

RE: Practicality of solution annealing heat treatment of Stainless steels?

Grain size increases with temperature, as you know. What is less obvious is that the tendency to sensitize increases with increasing grain size. So, if you don't have a low carbon chemistry, you'll invite problems.
Also less known is the fact that austenitic and duplex welds have significantly poorer corrosion resistance than the wrought base metal. A long anneal can reduce this problem. Patented versions of 304L and 316L have titanium additions to prevent this phenomena by gettering oxygen and sulfur before they can cause de-chromization.

RE: Practicality of solution annealing heat treatment of Stainless steels?

When you know that you can't postweld anneal you need to plan ahead.
You should always use low carbon grades to minimize sensitization.
You should also weld with filler metals that are alloyed to help improve the corrosion resistance of the welds.  In austenitic alloys this usually means higher Cr and Mo, along with higher Ni.  In duplex alloys the weld fillers have a different phase balance so that the un-annealed welds end up with the correct microstructure.
In a 3XX stainless I don't like annealing temps above 2150F.  But to be honest more damage is done during slow heating and cooling.  If you are annealing parts that must be heated and cooled slowly you need to really know what you are doing or you can end up worse off.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be slowed down.

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



News


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