Previous in Forum: Optimal Method of Distributing Edible Oil On Tanks   Next in Forum: Mechanical Press
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
4 comments
Rate this Comments: Nested
ddn.verma
Active Contributor

Join Date: Jul 2014
Posts: 15

Hardness-Difference Between Weld & HAZ for P91 Weldments?

11/10/2017 5:31 AM

Dear Sirs,

I wish to know, what should be the maximum difference in hardness between the weld & the HAZ in case of SA 335 P91 pipes welds after PWHT.

Thanks & regards,

D.D.N. VERMA
Register to Reply
Pathfinder Tags: Hardness difference between weld & HAZ of P91 pipe
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
3
Whitephone
Guru

Join Date: Jan 2010
Location: Mineral wells Tx
Posts: 630
Good Answers: 34
#1

Re: Hardness-difference between Weld & HAZ for P91 Weldments ?

11/10/2017 9:13 AM

The expected hardness range is 200-275 BHN. Keep in mind that hardness testing is only a sorting method and does not provide the total heat treatment condition of the P91 weld and base metal heat affected zone (HAZ). If necessary, surface replication should be used to evaluate the microstructure of the weld and HAZ to corroborate hardness test results. .

After PWHT, P91 is significantly more ductile. Its Rockwell C hardness drops to the low 20s and its Charpy V-notch toughness can increase to 40 to 70 foot-pounds, depending on the welding process.

So, this is the reason for not having to specify an acceptable hardness range in the

material specification. (i.e. ASME B31.3)
Register to Reply Good Answer (Score 3)
No more Good Answers.
lyn
Guru

Join Date: Oct 2008
Posts: 42377
Good Answers: 1691
#2

Re: Hardness-difference between Weld & HAZ for P91 Weldments ?

11/10/2017 9:14 AM

Why would you ask, unless someone has asked you?

Have you looked at AWS/ASTM/industry specifications?

ASTM A335/ASME SA335 P91 High Pressure Steel Pipe - Piyush Steel

Have you asked your pipe supplier?

Have you asked your welding supplier?

You could always weld up some samples and test them.

Or, if it's really important, have them tested by a certified test facility and get official results, not a guess.
Register to Reply
James Stewart
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 14331
Good Answers: 162
#3

Re: Hardness-Difference Between Weld & HAZ for P91 Weldments?

11/10/2017 1:17 PM

Whatever Whitephone lays out for you is gospel. Lyn is no newbie to these queries, either.

__________________
 If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Whitephone
Guru

Join Date: Jan 2010
Location: Mineral wells Tx
Posts: 630
Good Answers: 34
#4
In reply to #3

Re: Hardness-Difference Between Weld & HAZ for P91 Weldments?

11/10/2017 3:28 PM

you can believe it. Amen
Register to Reply
Register to Reply 4 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Copy to Clipboard

Users who posted comments:

James Stewart (1); lyn (1); Whitephone (2)

Previous in Forum: Optimal Method of Distributing Edible Oil On Tanks   Next in Forum: Mechanical Press

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Manufacturing:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (82 right now)
Show Members
Advertisement