Saturday, May 23, 2009

[MW:2227] Re: WPS/PQR for dissimilar joint

In general for 20mm thickness preaheting  not required (what is your desighn code?) whatever may be the diameter, unless the amb temp goes below 5 °C. In case if it required by your design code or by contract you can only preheat the CS side either by flame heating or by resistance/induction heating coils (preferable).
 
preheat temp depends on your design code. if required generally it is aprx 80 °C for this thickness.

assuming it is with ASME Section IX, you can qualify min 10mm thickness plate/pipe of similar combination of P numbers (i.e P1#P8).
 

 
On Thu, May 21, 2009 at 7:10 PM, PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com> wrote:
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 ?

2)What should be the appropriate preheat temperature and on what location to preheat?

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?

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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