Wednesday, June 23, 2010

RE: [MW:5727] Weld SA-106 to 9 Cr materials P No 5B gr 1 or gr 2

Dear Ahmed,

 

Kindly note that it's not recommended to Weld SA335 Grade P91 (Chromium Moly steels) to Carbon Steel SA106 Grade B for many reasons :

 

There'll be high tendency for the carbon atoms in the carbon steel to migrate to Chromium Moly steel to combine with the Chromium (Due to high affinity of carbon to chromium ) which in turn will softens the carbon steel to some extent ,Embrittle the HAZ & MAY result in depleted zone with very poor Mechanical Properties .( This carbon migration process is a Diffusion Metallurgical Phenomena which mainly depends on Temperature & Time and that's why it will happen during two stages during Welding Cycle itself & during PWHT which'll be mandatory for P91 steel).

 

From Design Point of View there's a high Strength Mismatch between the two Materials & the carbon steel  SA106 Grade B will not Mechanically Perform like SA335 Grade P91 neither at room temperature nor at Operating Temperature which definitely will be high temp more than 350C ( that's why SA335 Grade P91 had been selected for your application )

 

 

Tensile Strength of Carbon Steel SA106 Grade B @ 25C is 414MPa & @ 500C is 285MPa.

Tensile Strength of Low Alloy Steel SA335 Grade P91 @ 25C is 586MPa & @ 500C is 410MPa.

 

Regards

 

Mohamed.Hegazy

F.S.I Coordinador

AWS Certified Welding Engineer CWEng.

TWI CSWIP Welding Inspection 3.1.

AL JABER  Power & Energy Projects.
QATAR SHELL PEARL GTL Project
Ras Laffan ,Qatar

 

QATAR :  +9743694501 

EGY:       +20142345614

Email         : MH_w_INSPECT@YAHOO.COM

 

Tensile Strength of Low Alloy Steel SA335 Grade P91 @ 25C is 586MPa & @ 500C is 410MPa.

 

 

Mohamed.Hegazy

F.S.I Coordinador

AWS Certified Welding Engineer CWEng.

TWI CSWIP Welding Inspection 3.1.

AL JABER  Power & Energy Projects.
QATAR SHELL PEARL GTL Project
Ras Laffan ,Qatar

 

QATAR :  +9743694501 

EGY:       +20142345614

Email         : MH_w_INSPECT@YAHOO.COM



--- On Mon, 6/21/10, Ahmed Hafez <diesel2002@hotmail.com> wrote:

From: Ahmed Hafez <diesel2002@hotmail.com>
Subject: RE: [MW:5683] weld SA-106 to 9 Cr materials P No 5B gr 1 or gr 2
To: "Welding Material" <materials-welding@googlegroups.com>
Date: Monday, June 21, 2010, 2:59 PM

but P91 must be heat treated with temp. range 700-760 deg celsius  with no exemptions  as per table 132 ASME 31.1 require PWHT at temperature and the lower  phase transformation temperature for carbon steel is 723 deg celsius  . and temp. range for PWHT for CS is  600-650 deg celsius which is very far from P91 temperature ranges and consequaently make the weld joints to fail in hardness test requirements.
 

Date: Mon, 21 Jun 2010 04:45:24 -0700
From: kashkousha1@yahoo.com
Subject: Re: [MW:5682] weld SA-106 to 9 Cr materials P No 5B gr 1 or gr 2
To: materials-welding@googlegroups.com

dear ahmed
yes,by using ER 90S-B9(GTAW)&E9018-B9 (SMAW) or E 9015-B9
the joint should be heat treated acc .to ASME B31.3

 
H.KASHKOUSHA



From: Ahmed Hafez <diesel2002@hotmail.com>
To: Welding Material <materials-welding@googlegroups.com>
Sent: Mon, June 21, 2010 1:42:17 PM
Subject: [MW:5681] weld SA-106 to 9 Cr materials P No 5B gr 1 or gr 2

good morning every one
is it applicable to weld SA-106 to 9 Cr materials P No 5B gr 1 or gr 2
 
thanks and best regard


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