×
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

WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

(OP)
1. I am in search of a WPS for welding 11 mm thick pipe of A335  P22 with a pipe of HP Nb Modified material (35% Cr & 25% Ni) in the convection zone of ethylene furnace with zone service  temperature at approx.900 Deg C.

2. Do I need to go for PWHT in this case?

This is urgent. Please help.  

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

ak1965;
According to Section I, no PWHT is required for Grade P22 pipe that is 16mm or less at the weld region. I would use a preheat of 400 deg F with Inco Weld A filler metal. Perform a Liquid PT after the completion of the weld.

Here is an interesting paper on the subject of repairability of the heat resistant stainless steel castings.

http://www.aws.org/wj/supplement/WJ102010_210.pdf

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

(OP)
Metengr


Thanks... In our case.. the thickness is approx. 11 mm and at the weld it would be around 13 mm. which is the threshold limit of carryinbg out PWHT for CR Mo steel ( P22) as per ASEM b31.3 table 331.3.2.

since it is dissimlar metal joint with HP Nb mod. material, shoud we condier PWHT in thsi case.

Please comment.

  

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

ak1965;
If you are following minimum code requirements, you do not need to PWHT the P22 base material in the weld region. The dissimilar material does not require PWHT because it is a heat resistant stainless steel.

Now, if the P22 material was cold formed or strained with no post-forming thermal treatment near the weld region, I would PWHT. Otherwise, if the material has not been cold worked or cold strained, no I would not perform PWHT.

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

(OP)
P22 material is already in service at around 900 DegC.since last 15 years and the lower HP Nb modified material (35% Ni 25% Cr) is new component to be welded.  

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

(OP)
metengr,


Waiting for your response for PWHT on the above information gievn by me regarding service temp of F 22 material that i sto be welded with HP Nb Mod.


Plz. comment.
 

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

You need not PWHT.

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

ak1965
I would not PWHT.

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

As far as I know, for  welding with Inco welding rods, PWHT is not rquired. Further, heat treatment for HP Nb mod is solution annealing (app 1100 deg C with quenching)  and for P22 it is PWHT at app. 720 deg C with controlled cooling. My doubt is usability of A335P22 at 900 deg C . I think at convection zone, the temperature will be around 500 deg C max.

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

(OP)
Temp. may not be 900 Deg C at this weld joint, It is backed with refractory and temp should be in the range of 700 Deg C.

We got some WPS from elsewhere that suggests PWHT on this dissimilar metal joint. Pl. Note that F22 (aged 15 yrs.) to be welded with HP Nb mod 35% Ni & 25% Cr (New).

Wall Thickness of weld portion is 11 mm.
  

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

We have made these joints many times without PWHT.

RE: WPS A335-P22 to HPNB Modified (35% Cr, 25% Ni)

It is my understanding that it is recommended to make this DMW  as a machine weld, and not a manual weld- to ensure adequate weld penetration, weld spatter would be expected, and most manual welders would tend to avoid the spatter and turn down the amps, which would prevent adequate penetration.

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