MPI for duplex stainless steel

[Mohd Siraj]

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?

[Dilli Babu]

yes because its ferrite 50%+austenite 50% but magnetic permeability is very lesser than ferrite steel.   

--
https://materials-welding.blogspot.com/
https://www.linkedin.com/groups/122787
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-weld...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/eb9b8ceb-4164-459d-ac06-9d51033706dan%40googlegroups.com.

[Sachin Fatangare]

As per my understanding duplex SS has combination of ferrite and austenite microsturcture. These two types of grain structures  have different magnetic permeability which can cause false indications Or indications may not be visible properly.

--

[Moossa Kutty]

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

--

[Ahmad el-sharkawy]

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.

To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAKgLv__ygYTZsADnA4F-XFqy0G86LV7cZxbyzO-Q2dMi4D1Vww%40mail.gmail.com.

[pgos...@rogers.com]

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:pgos...@rogers.com,pradip....@gmail.com

Cell/Whasapp:1-905-9793232

 

MPI on duplex stainless steels (ndt.net)

 

2205 duplex/ MPI (ndt.net)

To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAK-7o_PnE%3D0rg68EpuG1nsh8sBYwSVmQwNd5YtOSWVv1fcHwKg%40mail.gmail.com.

Virus-free.www.avg.com