[MW:2770] RE: 2764] RE: 2746] RE: 2736] Re: 2733] RE: 2729] Ferrite Number (FN) for the deposited weld metal

 

 

Hi

 

The DeLong and Schafler diagrams have long been surpassed by the WRC diagrams which are more accurate and only use ferrite number. The debate regarding % ferrite has been settled aand it has been conclusively shwn that you cannot acurately and repeatabily measure the percentage ferrite.

 

Attached is a documentfrom the international institute of welding regarding ferrite measurements. It remains only as good as the calibration and experience of the erson measuring .

 

Regards

John du Plessis

Technology Manager

 

Tel: +27 (11) 298 2100

Tel: +27 (11) 298 2103 (Direct)

Fax: +27 (11) 836 6014

Mobile:+27  (11) 82 883 4970

www.saiw.co.za

 

This email and any files transmitted with it are confidential and may be legally privileged. They are intended solely for the use of the individual or entity to whom they are addressed. Access to this e-mail by anyone else is unauthorised, and any disclosure, copying, distribution or other use of this e-mail is prohibited and may be unlawful. We will not under any circumstances have any responsibility or liability arising out of or in connection with any unauthorised use of this e-mail. If you have received this email in error please notify the sender before deleting it.

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of PB HEGDE
Sent: 22 July 2009 06:53 AM
To: materials-welding@googlegroups.com
Subject: [MW:2764] RE: 2746] RE: 2736] Re: 2733] RE: 2729] Ferrite Number (FN) for the deposited weld metal

 

Hi!

In my Opinion  Delong Digram shows thw Ferrite in  % and some of the Ferrite meters give Ferrite %   which I have used ( TWI make )

 

Regards

 

Hegde

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of John Du Plessis
Sent: Tuesday, July 21, 2009 7:44 PM
To: materials-welding@googlegroups.com
Subject: [MW:2746] RE: 2736] Re: 2733] RE: 2729] Ferrite Number (FN) for the deposited weld metal

 

 

 

Good day

 

I find it necessary to interviene at this point in time.

 

Firstly ferrite content in a weld is expressed as ferrite number (FN) and never as a percentage as no two persons on earth can agree to the percentage ferrite in a weld. There is no direct correlation between the ferrite number and the % ferrite in the weld.

 

In welding austenitic stanless steel we normally require between 4 to 7 FN ferrite in order to ensure that no hot cracking takes place in theweld metal. Pure austenitic weld metal is extremely susceptabe to hot cracking.

 

Numerous studies have show that the heat inut during welding does not have a significant effect on the ferrite number in the normal welding ranges but a very low and very high heat inputs there are some affects.

 

There are a number of diagrams which can be used to calculae ferrite numbers based on the chemisty. Previously the Delong diagam was mentioned but there ae others including Schaefler, WRC 92,  which is more recent and gives additional data.

 

The issue with getting different ferrite numbers from the same pack of consumables are mostly related to the welder in terms of arc length control Nitrogen has a significant influence on the Ferrite number and een a very small percentage entering the weld metal through using a long arc length will have significant variaion in ferrite number.

 

 

John du Plessis

Technology Manager

 

Tel: +27 (11) 298 2100

Tel: +27 (11) 298 2103 (Direct)

Fax: +27 (11) 836 6014

Mobile:+27  (11) 82 883 4970

www.saiw.co.za

 

This email and any files transmitted with it are confidential and may be legally privileged. They are intended solely for the use of the individual or entity to whom they are addressed. Access to this e-mail by anyone else is unauthorised, and any disclosure, copying, distribution or other use of this e-mail is prohibited and may be unlawful. We will not under any circumstances have any responsibility or liability arising out of or in connection with any unauthorised use of this e-mail. If you have received this email in error please notify the sender before deleting it.

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of suneel gore
Sent: 21 July 2009 01:36 PM
To: materials-welding@googlegroups.com
Subject: [MW:2736] Re: 2733] RE: 2729] Ferrite Number (FN) for the deposited weld metal

 

Dear Rishi RAJ                                   date 21.07.2009 Yes you are right , The heat in put(Or the cooling rate ) have definately have effect on some grades of SS Mainly 304 & 316 Regards suneel Gore   --- On Tue, 21/7/09, Singh Rishi (TIPO - QA/QC) <R.Singh@Panipat.ticb.com> wrote: From: Singh Rishi (TIPO - QA/QC) <R.Singh@Panipat.ticb.com> Subject: [MW:2735] RE: 2733] RE: 2729] Ferrite Number (FN) for the deposited weld metal To: materials-welding@googlegroups.com Date: Tuesday, 21 July, 2009, 4:49 PM Thanks  Mr. Hegde, Can heat input , be a variable for erratic ferrite no ? For example I’m using filler wire of the same batch no ( packet ) & welder , but in one joint I get Ferrite no. less than 8 % and in other joint I get over 10%.   Best Regards, Rishi Raj Singh From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of PB HEGDE Sent: Tuesday, July 21, 2009 1:57 PM To: materials-welding@googlegroups.com Subject: [MW:2733] RE: 2729] Ferrite Number (FN) for the deposited weld metal       Austenetic SS used in chemical /petrochemical plant require  good Corrosion resistance. For which delta ferrite plays the major role. i)Increase in Delta Ferrite will reduce the corrosion resistance . Therefore in severe corrosion resistance requirement  , ferrite to be kept below 8% (Generally it is kept between  3-7 %)However  very low ferrite  causes defect like hot crack, fissures ,There is no code requirement but Ferrite requirement is decided by process licenser ,depending upon the service condition ii)You can check ferrite No by Instrument called Ferrite Meter where you can get Ferrite No directly ,Some time You can check with respect to Delong Diagram ( Given in ASME Sec 2C ) by calculating /plotting the Cr , and Ni equivalent from actual chemical analysis of weld   iii)My experience –some time Ferrite no increases due to work hardening of material If you measure by Ferrite meter Regards   Hegde P.B. 09714714803   From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of tong tong Sent: Monday, July 20, 2009 9:31 AM To: materials-welding@googlegroups.com Subject: [MW:2729] Ferrite Number (FN) for the deposited weld metal   Dear All, Regarding above mentioned subject, i would like to know in detail about ferrite number. I have a few questions to ask such as What is the ferrite number? Why it is so important? Materials subjected to ferrite number? Permissible limit of ferrite number? Code and standard that we refer to requirement of ferrite number? Procedure to perform ferrite number?..If anybody have experience or information regarding this subject hopefully you can share with me. Thank in advance for your kind cooperation Regards tong2     Looking for local information? Find it on Yahoo! Local</a

 

 

 

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