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[MW:2275] Re: 2224] WPS/PQR for dissimilar joint

By Materials & Welding
Hi,
 
Regarding the foot note, Metallurgically, 0.01% of C equivalent to 0.06 % Mn ; that is why in all specification you could find this general comment.
 
So, if Mn increases to 1.36 % , there will be a definite reduction in Carbon percentage.
 
For, CE  = 0.47 , preheat 95 deg Cel is enough to get the good results,
 
As CE increases your weldability decreases, but you cannot directly relate the Mn to weldability.
 
Thanks & Regards,
 
K.Babu

Singapore

 
On Wed, May 27, 2009 at 11:29 PM, PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com> wrote:

Dear Sir

Thanks for your valuable advice. However we have landed up in one more hurdle in same job discussed below.

The SA105 forging is having Mn content on higher side i.e 1.19%.
as against specification of 1.05% max.
There is a footnote stating that as per --- Mn=1.36% max is also allowed.
The Carbon content is 0.22%.
Due to high Mn content the CE is 0.47.

Now with such high CE should we preheat the joint to the same temp. of 75DegreesC adviced by you ??
Will this high CE of 0.47 and high Mn content affect the weldability of CS#SS joint?

Also as per ASME Sec VIII Div 1, Non-mandatory appendix R (R1 & R7), preheating is not required for this P1#P8 joint.

But client is adamant and says that Non-Mandatory appendix should never be followed. Is this approach true.
Client is telling that only Mandatory appendix should be followed !!

Please advice !

Regards

Prem Nautiyal
Godrej, Mumbai.

On Sat, 23 May 2009 12:42:19 +0530 wrote

>My opinion is given below against each query
>
>
>
>Hegde P.B.
>
>
>
>
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>From: materials-welding@googlegroups.com
>[mailto:materials-welding@googlegroups.com] On Behalf Of PREM SHANKARDUTT
>NAUTIYAL
>Sent: Thursday, May 21, 2009 8:41 PM
>To: materials-welding@googlegroups.com
>Subject: [MW:2224] WPS/PQR for dissimilar joint
>
>
>
>Hi friends
>
>I want the advice of senior members to help me out in qualifying a typical
>welding procedure as per ASME Sec IX.
>
>We want to weld a 800mm dia. SA105 Gr.B (Carbon steel)forging to a 20mm
>thick SS304L shell (circumferential seam).
>Length of both members is @ 2metres.
>
>The solid forging is tapered and is welded to the 20mm thick SS304L with a
>full penetration joint where the depth of bevel is 18mm and thickness of
>both members at the joint is 20mm.
>The joint is single V. Only final weld LPT required.
>
>Now logically this 800mm dia. forging will have to be preheated to @150
>degrees celcius i believe, but what about SS304L.
>Our client has strictly told us that SS304L shell shall not be preheated.
>The reason being distortion and a wider HAZ, however i believe that
>preheating to 100/150 degrees celcius will not change the structure of
>SS304L and hamper mechanical properties - UTS and bend.
>
>Now i have 2 queries:
>
>1)Should we only preheat the CS forging and mention the same on the WPS ?
>
>a)Option 1-You can preheat only CS side to say 75C and weld the joint with
>E309L with interpass restriction of 175C
>
>b) Option 2 - If client requirement is very stringent- Butter the weld edge
>of CS forging by E309L with preheating of 75C , (Separately) and later join
>the SS to CS forging by E309L  / or 308L weld w/o preheating
>
>
>
>2)What should be the appropriate preheat temperature and on what location to
>preheat?
>
>As Joint thickness is 20mm ,You can keep pre heat temp. of 75C on CS side
>about 50 mm band width
>
>
>
>3)On what plate thickness should i qualify the Welding procedure inorder to
>qualify the base metal thickness range i.e for 800mm dia. forging?
>
>Min 10mm thickness of plate of CS and SS(For dissimilar metallurgy)  The
>effective thickness of joint  joint is 18mm ( you are not joining directly
>to 18mm shell to 20 mm forging)
>
>
>
>4)Should i qualify the joint on a dissimilar thickness with weld deposition
>of only 20mm, so what thickness of plates should i select?
>
>Please advice !
>
>Regards
>
>Prem S Nautiyal
>Godrej, Mumbai.
>
>PREM S NAUTIYAL
>
>CELL : 9820313278
>
>
>
> >atureline.htm@Middle?> >

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>

PREM S NAUTIYAL

CELL : 9820313278


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