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RE: [MW:33413] MPI for duplex stainless steel

By Materials & Welding

Hi Siraj,

Please look at the attached links below. Duplex has a complicated microstructure. Ferrite is magnetic, austenite is non-magnetic. The volume % of ferrite is not fixed. In welds % Ferrite changes due to changes welding process parameters. In casting due to changes of casting parameters , cooling rates.

 

Hence there would always be a weak & inconsistent magnetic permeability which could leads to " spurious indications"  and unreliable results.

 

Hence, it's a common practice to go with LPI for surface and subsurface inspection.

 

Thanks.

 

Pradip Goswami.P.Eng, IWE.

Independent Welding & Metallurgical Engineering Specialist.

Linkedin: https://www.linkedin.com/in/pradip-goswami-2999855/

Email:pgoswami@rogers.com,pradip.goswami@gmail.com

Cell/Whasapp:1-905-9793232

 

MPI on duplex stainless steels (ndt.net)

 

2205 duplex/ MPI (ndt.net)

From: materials-welding@googlegroups.com <materials-welding@googlegroups.com> On Behalf Of Ahmad el-sharkawy
Sent: August 30, 2022 1:02 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:33411] MPI for duplex stainless steel

 

DSS is not good magnetize because it's structure Consists of two dual phase;  paramagnetic phase  called austinite 50% and magnetize phase called ferrite 50% , so you will find moderate magnetization not be well in inspection, it's better if you use PT method instead of MPI.

 

On Tue, Aug 30, 2022, 7:51 AM Moossa Kutty <moossakuttypk@gmail.com> wrote:

Magnite not catch properly on the DSS materials , so result is wrong, as per MPI procedures not allowing also 

 

On Mon, Aug 29, 2022 at 5:52 PM Mohd Siraj <mohd52100@gmail.com> wrote:

hi gents,

 

can we do Magnetic particle test for duplex stainless steel

 

i believe we can do since DSS is ferromagnetic material

 

whats expert opinion?

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