Raw stock material testing discrepancy using an XRF (x-ray fluorescence) analyzer

Michael_M

Trusted Information Resource
We have an internal process of scanning raw stock material using an XRF (x-ray fluorescence) analyzer (our analyzer is the Hitachi X-MET8000 Optimum). We had a piece of Aluminum Nickel Bronze (AMS 4640H) fail showing the Zinc content at .36%. Per the standard, the Zinc should be between 0-.3%. I then sent a piece of material to a secondary testing lab who showed the Zinc at .41% (using ASTM-E1086/14 MOD--honestly I don't know anything about this standard).

I contacted our vendor who requested a small piece of material for additional testing. They sent the material to 2x different labs.
Lab 1: .26% Zinc using test method ASTM E1621 (again, I know nothing about this spec).
Lab 2: .06% Zinc using specification ASTM E2 SM 5-17 (again, I know nothing about this spec).

The original mill certification shows the Zinc at .07%.

Question 1: Has anyone ever come across this type of discrepancy?
Question 2: Does anyone know if there is something about Aluminum Nickel Bronze that can cause such a wide variance in readings?
Question 3: How would you proceed to try to find the 'cause' and correct the discrepancy given such a wide range of readings?
 

Coury Ferguson

Moderator here to help
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Have you verified your analyzer is working properly? Meaning a known good and known bad material. You have 2 labs that say the material is within specification of Zinc and the mill certification. Maybe you want to checked your analyzer. It might be giving you incorrect readings.

Just my opinion.
 

Michael_M

Trusted Information Resource
Have you verified your analyzer is working properly? Meaning a known good and known bad material. You have 2 labs that say the material is within specification of Zinc and the mill certification. Maybe you want to checked your analyzer. It might be giving you incorrect readings.

Just my opinion.


We have a 'calibrated' sample of aluminum that has zinc in it that we test against. Additionally, the secondary testing lab we sent the material to show the material out of spec at .41%.
 

Coury Ferguson

Moderator here to help
Trusted Information Resource
We have a 'calibrated' sample of aluminum that has zinc in it that we test against. Additionally, the secondary testing lab we sent the material to show the material out of spec at .41%.

This is definitely a dilemma. You have 3 people that say it is within specifications and you have 2 saying it is not.

What is the application of the material?

It might get down to calling it one way or the other. The grey area.

I wish I could help you more.
 

Michael_M

Trusted Information Resource
This is for Aerospace, and I have requested assistance from our customer. I am just scratching my head trying to figure out what a next step is.
 

Al Rosen

Leader
Super Moderator
Your hand held XRF may not be as accurate as the other methods being used. You should find out the details of the methods and instruments being used?
 

Al Rosen

Leader
Super Moderator
This is for Aerospace, and I have requested assistance from our customer. I am just scratching my head trying to figure out what a next step is.
My aerospace customers required benchtop XRF. Handheld XRF are not as accurate.
 

Michael_M

Trusted Information Resource
I probably did not write this up very well. There was a total of 3 independent lab tests that show the material with a huge range. Our XRF is used internally to verify material.

Labs used by Material vendor
Lab 1: .26% Zinc using test method ASTM E1621
Lab 2: .06% Zinc using specification ASTM E2 SM 5-17

Lab used by us when material failed internal testing:
Lab 3: .41% Zinc using test method ASTM-E1086/14 MOD

Our use of the XRF gun was what triggered the lab checks.
 
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