Wednesday, July 21, 2010

Re: [MW:6047] How Delta- Ferrite prevents Solidifacation Cracking/ Hot Cracking in SS??

Hi,
We have come across, with very low delta ferrite ( 0.5- 1.5%) in the weld, leading to cracking & failure of components. With high % of delta ferrite also (10%), cracking is observed (even during storage). Minimum 3% is required to avoid fissuring. Low and high FN-both are not advisable. I can explain afterwards, how it prevents.
Regards,
Vaidehi Ganesan.
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----- Original Message -----
Sent: Wed, Jul 21, 10 9:43
Subject: [MW:0] How Delta- Ferrite prevents Solidifacation Cracking/ Hot Cracking in SS??

Dear All,
Good Morning
I have query regarding the solidification Cracking.
Generallly, FeS the compound responsible for solidification cracking. Also Arsenic, Sulphur shows same phenomenon.
Now Delta- Ferrite in 3-8 FN proportion prevents hot cracking.
But how ?? In most of the books, it is written that, " Delta- Ferrite has tendency to lock the impurities".
But how Delta- Ferrite can be helpful for the prevention of hot cracking by locking the impurities??
Also, what happens if Delta- Ferrite is very low of the order of 0.5 FN or so or what happens if Delta-Ferrite is high of the order of 15 FN or so.
 
 
Dear All,
Please help me to find the answers.
 Thanks in advance.
 
Jignesh
 

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