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No Alloy Grade Match? Quick Ways to Fix It on Your Handheld XRF Analyzer

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Alloy analyzer gun

No grade match can sometimes occur when testing alloy samples using handheld XRF. In this XRF user guide, we’ll review reasons for no alloy grade match, explain how to fix it, and share ways to obtain the appropriate grade match for your alloy sample.

Reasons for No Alloy Grade Match on Your Handheld XRF Analyzer

As an example for this guide, I tested a nickel alloy Monel K500 sample using the Vanta™ handheld XRF analyzer. The message “no grade to compare” appeared for this alloy on the user interface. To better understand why this happened, let’s look at the chemistry from the XRF test to see what it can tell us.

Handheld alloy analyzer

Vanta XRF result with no grade match

We can see clearly that we are testing a nickel alloy, as indicated by the 75% nickel (Ni) in this sample. So why wasn’t this a match? The most common reason for no match is contamination. This might happen because the sample is painted, plated, or coated. Looking at our sample, however, contamination doesn’t seem to be an issue.

Nickel alloy Monel K500

Nickel alloy Monel K500 sample

Although far less common, the “no grade to compare” message can also occur when an alloy grade isn’t included in the Vanta grade library. To check this, press the grade match icon (outlined in red below) at the bottom of the Vanta screen.

XRF alloy analyzer

Vanta XRF results with the Grade Match icon outlined in red

Scroll down to the libraries section (outlined in red below) and select the library to open the list of alloys included in the active library.

Alloy grade library for handheld XRF

Library section in the Grade Match Menu

Alloy grade library on an XRF gun

Common Library in the Grade Libraries Menu is selected

We can see that our sample, Monel K500, is already included in the selected Common library.

Alloy grade library on a handheld XRF analyzer

Monel K500 is included in Common Library on the Vanta analyzer

If you know what the material is, we suggest adding this grade to the library as a comparison against your sample to see why your sample is out of specification. For instructions on adding a sample to the library, watch the video tutorial below:

Other XRF Tips to Obtain a Correct Alloy Grade Match

Now that we have ruled out contamination and our sample is in the grade library, what else can we do to obtain the correct alloy grade match?

Let’s go back to the grade match screen. Notice it reads “show match no <4” at the top. The match number is an indicator of how closely the chemistry of your sample matches the specified values for a grade. A value of 1 indicates a close match, while a value of 10 indicates a poor match to the grade specifications. You can edit this as needed to allow for variations in the materials you’re testing.

Handheld XRF analyzer for alloy identification

Grade match screen with Show match No set to 4

We will increase the match number to 6 so that more grade matches will display. Now let’s retest our nickel alloy sample.

Handheld XRF analyzer for alloy analysis

Grade match screen with Show match No set to 6

The analyzer has successfully identified the sample as Monel K500.

Alloy identification using an XRF gun

Vanta XRF result with Monel K500 identified

Also note that under the sample name the match value for this sample is 5.0 (outlined in red above). Since we previously specified the match number had to be <4, the Vanta analyzer reported no grade match to compare. Now that we increased our match value to <6, we can display the alloy.

Looking at the chemistry, you can see that the nickel (Ni) and copper (Cu) values have been outlined in red, indicating that these fall outside the range specified in the grade library for Monel K500. This is why the match number was high and the message “no grade to compare” originally displayed: the material is out of specification.

Alloy identification using a handheld XRF gun

Vanta XRF result showing Ni and Cu out of spec for Monel K500

The red outline enables you to quickly see which elements are causing an alloy to fall out of specification and make any necessary changes to account for this. You may also notice during testing that a grade match initially displays before no grade match appears as the test finishes. As the precision of the measurement gets better, we penalize the match number more for being out of specification, causing no match to come up.

I hope this no match troubleshooting guide was useful! You can also watch our video on the process:

Related Content

Video: What Does “No Match” Mean?

Webinar: Get the Most Out of Your Alloy Analysis

Using XRF to Quickly and Accurately Sort Low-Magnesium Aluminum Alloys

Applications Scientist, Analytical Instruments

Andrew Cardamone has a bachelor’s degree in chemistry and environmental studies from Bowdoin College. From 2018–2022, Andrew was an applications scientist at Evident specializing in X-ray fluorescence (XRF) and other analytical technologies for geochemical, soil, and car catalyst applications. Prior to Evident, Andrew spent seven years working as a material analytical chemist.  

April 27, 2021
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