Here’s another great carbon story and learning opportunity, courtesy of our EMEA manager Jeroen. Only the names have been redacted to protect the innocent….
This demo took place at ØØØØØØØØ in the Netherlands with 5 people, including their OES operator and 2 guys responsible for the NDT part of ØØØØØØØØ in the Netherlands. ØØØØØØØØ is a global testing company, and is getting into PMI work. They compete with TUV and the others. I took out the Z-200 C+, and their first response was, “WOW, can that thing do Carbon analysis?!” Which was a good start of the meeting. We discussed SciAps, the history of the Z-series and the current development of the Z-200 C+. During this time we let the Z warm up so that it would be ready for the demo. We started talking about the L-grades and I showed them the OES type SW and the Carbon Offset correction. The OES guy loved it! He started asking about the warm up time, Argon flush time, etc. I explained him that the warm up time varies depending on how you warm up the instrument, by shooting material or just leave it idle. I shot my 316 and showed them the result, we were 0.008% of from the cert value so we tuned Carbon offset and analyzed the 316 again with a result being spot on! Next I showed them the L-grade, again we were spot on!
Next the ØØØØØØØØ guys gave me two samples, one with a cert and one customer sample without cert. Both were low-alloy steels. I explained that this is a different calibration so I took out my low alloy steels and tuned it on my sample with 0.2% carbon. I got good results so we measured the sample from ØØØØØØØØ with cert which contained 0.22% Carbon and we got an average of 0.21%. They got really excited, so we moved on the customer sample and analyzed it.
Here’s where things get interesting. We got 0.15% as average. The OES guy from ØØØØØØØØ took out his report from the ØØØØØØØØ Mobile OES system which showed 0.2%. All the ØØØØØØØØ guys were like, “OK so it works on CRMs but does it work on real world samples?” I did another grinding on the customer sample and measured it again, we got an average of 0.16%. Next we analyzed their certified sample again and got 0.22% as average. Thirdly we analyzed my low alloy steel and got 0.2% (certified C value is 0.2%). By this time, we were all convinced that the instrument was working correctly and that the OES would be off, the question was by how much it was off. The OES guy decided to call the customer and ask for the material report. About 15 minutes later the customer calls back with the material spec: Carbon concentration in the sample should be 0.162%.
Everyone in the meeting was convinced that the Z-200 C+ is great instrument! The OES guy wants to have three (one for each location in the Netherlands) but the manager was more reluctant, his problem is with the name LIBS technology. Apparently more and more companies are specifying which analysis technique should be used and they state OES as the technology. We forwarded them the ASTM E1476 document which states that a laser can be used as a source for OES.
Important take-aways here:
- Make sure you have CRMs
- Make sure analyzer is warmed up and tuned in on your CRMs
- Don’t always believe OES! It’s complicated, even more sensitive to temperature and vibration.
Share This Post