[MW:13745] RE: How to reduce SA517 hardness

Pradip,

You need to  have these information prior hand:-

• Chemical composition and mechanical properties and the heat testament, especially Quenching and Tempering Temperature  of this steel , which is deemed equivalent to SA 517.
•  SA517 have 6 grades , A,B,E, F,H,P,Q, what was the grade used?
• Calculate what is the C.E of this steel, for the ease of determining  the cracking tendency, effectiveness of preheat, IPT
• MTR of the welding electrode, E-11018M from the supplier. What was the all-weld hardness on the electrode MTR. What was the diffusible hydrogen ranking of this electrode, H4 or H8
• The preheat and the IPT, got slightly mixed up (see below). I would think this as recommended.
• Assuming both of these parameters are in the acceptable  and are within range of fabrication guidelines, the recorded hardness in the weld metal is really high. A structural weld with such high hardness values may experience  service induced damages later.
• As a last resort in order bring down the hardness value you may have to perform PWHT, follow the guidelines of UHT-56 (Sec VIII, DIV-1). However ensure that PWHT temperature should be well below the tempering temperature of this steel.You may have to discuss this issue with the plate manufacturer.

 

I'm certain the above recommendations would be of help  to you.

 

See these links below, which would be of good guidance on SA517 and other T1 steels.

 

Thanks.

 

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario, Canada.
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net

-----Original Message-----
From: pradip kumar sil [mailto:pradipsil@gmail.com]
Sent: Sunday, February 19, 2012 3:43 AM
To: materials-welding@googlegroups.com
Cc: pgoswami
Subject: How to reduce SA517 hardness

Dear Sir,
We are using one material which is equivalent to SA-517 material ( Pressure  vessel plates, alloy steel, high strength, quenched & tempered ). with electrode E-11018M. Climatic condition of the environment is minus 5 degree Centigrade to plus six degree Centigrade.Parent material hardness is 230 BHN but weld material hardness is coming approx 400 BHN  which is not acceptable. We are properly maintaining preheating  i.e 250 degree Centigrade as well as interpass temperature is 150 degree centigrade.
Pls guide me how can i reduce this material hardness.
Regards
Pradip