My opinion is given below against each query
Hegde P.B.
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
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