Re: [MW:10675] EPMA test for single layer ESSC Overlay

Kindly go through the volume of material analysed, provided in the manuals for both the cases.

 

1) Spectroscopy

2) EPMA ----[spot size, pixel count and depth of material analysed]

3) Wet chemical method [for comparision]

 

FACT: Concentration of elements varies from point to point.

 

So lesser the volume of material analysed, more unique/ accurate will be the value at that location or higher the volume analysed an average value of the elements will be obtained [as in spectroscopy and wet chemical analysis methods]. Hence the difference in the values. If you go for EPMA then you need to have less dilution from base material or high alloyed 347 consumable.

 

Regards,

Ravi

 

On Tue, Apr 12, 2011 at 10:38 AM, Jignesh Desai <jignesh.desai.met@gmail.com> wrote:

Further to my below mail, we carried out EPMA testing of SS 347 weld over lay on SA 387 Gr 22 Cl 2 (P-5A) base material by Electro Slag Strip Cladding.

 

During the review of report few non conformity found with respect to % Cr & % Ni as per attached.

 

Also we have carried out Spectro analysis for the same and found satisfactory.

 

Can some somebody guide on above issue?.  Would like to know any accuracy level/tolerance limit for the EPMA testing machine. Also what could be reasons for the variation in % elements  with respect to spectro analysis.

 

Regds/Jignesh

---------- Forwarded message ----------
From: JJD

Date: Wed, Oct 13, 2010 at 11:26 AM
Subject: [MW:7529] EPMA test for single layer ESSC Overlay
To: "materials-welding@googlegroups.com" materials-welding@googlegroups.com

 

One of our job require PQR with chemical check across the transverse cross-section of the weld overlay using EPMA (Electron Probe Microanalysis) Technique.

Can somebody inform me the detail of laboratory which perform this test?

Regds/Jignesh

 

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