General Testing Protocol; Undersized Or Non-Contact Samples; Instrument Qc - Thermo Scientific XL2 User Manual

GENERAL TESTING PROTOCOL

UNDERSIZED OR NON-CONTACT SAMPLES

Thermo Scientific
Good surface preparation is essential for obtaining accurate test results. All non- representative
material (e.g., paint, coating, scale) must be removed prior to testing. An approximately
2-inch-square section of surface should be cleaned down to the material to be analyzed. See
the Resource Guide for information on Sample Preparation.
The analyzer will often display a correct alloy identification and/or accurate chemistry result
before the specified time interval. If the accuracy meets the user's requirements, it is not
necessary to measure for the full time.
Longer measurements might be necessary if low concentrations of elements must be
determined.

INSTRUMENT QC

Measure the supplied reference calibration check sample AT LEAST once a shift. If correct,
continue work. If incorrect, redo System Check and re-take the past 2 hours of results.
(Samples that do not make contact with or that do not fully cover the measurement aperture)
For samples that do not fully cover the measurement aperture, increase the testing time by
increasing the time in inverse proportion to the decrease in percentage of aperture covered.
For example: a rod only covers ½ of the aperture, so increase the measurement time by two
(e.g., from 10 to 20 seconds per filter for alloy chemistry).
The best procedure to measure undersized samples is to use the Thermo Scientific Niton
portable test stand (optional), which is shielded to prevent radiation exposure to the operator.
An undersized sample may alternately be measured while lying on another material. Results
may be affected by the signal coming from the underlying material itself. Use only pure
aluminum, pure plastic, or clean wood and employ the Disable Al feature. Use the Tools
Menu, then select Disable Al, and check the underlying surface itself to be sure no metals are
present. Be sure to use the Tools Menu and select Enable Al before testing aluminum alloys.
3
How to Analyze
General Analysis
Niton XL2 Analyzer User's Guide 27