Re: [MW:8263] How to control cracks when weld P91 and P91

A) Cracks in theweld and HAZ depends upon varios factors like

i) Not meeting Uniform through thickness preheating heating and post heating

ii) Weld configuration and temporary supports /stiffeners( excessive stiffener) causing restraint joint including excesive root gap

iii)Weld  and Base metal chemistry having higher Mn,P,S

iv)Improper root run (Effect of oxidation on otherside of root)

 

For improving Impact value

The weld bead configuration and thick ness plays imporatant role in addition to heat input

 

Regards

Hegde P.B.

 

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From: Roy LIU刘艺 <standardliu@hotmail.com>
To: materials-welding@googlegroups.com
Sent: Sun, 14 November, 2010 5:59:37 PM
Subject: [MW:8258] How to control cracks when weld P91 and P91

Dear All,
I just meet a problem from one of my customers.
It is a Boiler Manufactory in China.
 
Details as follow:
base material: P91
process: SMAW (root) + SAW (filler metals)
Heat Input: high  
I=380A
U=35V
V=250mm/min
Preheat, Interpass Temperature: ≤250℃
 
How to control cracks?
How to increase impact properties afer PWHT?

 

Best regards

 

Roy LIU

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