Hi,
I think The cooling rate leads to high ferrite content.
To reduce the ferrite percentage/Ferrite number,Treating the high FN welds with a wash using the Tig arc, but no wire after the weld is completed, acts like a heat treatment and gets the Ferrite down.
Thanks & Regards,
(Karthik)
Karthikeyan.S QA/QC Manager Getabec Energy Co.,Ltd. 379,Moo6,Soi8,Nikhomphatana, Rayong-21180, Thailand. Phone: 0066 38 897035-8 (Off) Fax: 0066 38 897034 Hand Phone: 0066 892512282
--- On Wed, 12/22/10, Srini <sethu.srini@gmail.com> wrote:
From: Srini <sethu.srini@gmail.com>
Subject: [MW:8862] Duplex S.S - How to reduce ferrite content in HAZ
To: "Materials & Welding" <materials-welding@googlegroups.com>
Date: Wednesday, December 22, 2010, 2:44 AM
Can you please advice some thoughts how to reduce ferrite in HAZ and bring into range of 60% max. This is an weld procedure development and ferrite was as high as 71% (E562 - Metallography method) in HAZ. Ferrite in parent metal 50%, ferrite in weld metal was 50 to 55%. The details of the processa are as below. Material Dual S32205/S31803. Thickness 1.25" (32mm). Process- SAW. Double butt joint. Parameters 450A/30V/20". Heat input was 42Kj/inch. After each pass i let the part cool naturally to about 80° and then welded the next pass. i continued the same to keep the cooling rates consistent. May be i have put too much control and resulted in faster cooling rate and hence high ferrite in HAZ. No intermetallic phases found. ASTM 923 C - no corrosion loss, but the customer would not accept 71% ferrite in HAZ. has to be less than 60% to avoid pitting corrosion. Thanks for any help in advance. -- To post to this group, send email to materials-welding@googlegroups.comTo unsubscribe from this group, send email to materials-welding+ unsubscribe@googlegroups.comFor more options, visit this group's bolg at http://materials-welding.blogspot.com/The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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http://materials-welding.blogspot.com/ The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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