Positive Material Identification (PMI)

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Among the duty of A Welding Inspector during PREPARATION (BEFORE WELDING) is to verify and make sure that :

1. The Material (pipe) to be welded is correct
2. The electrode is correct
3. The Welder is correct
4. The WPS and PQR is correct
5. The joint preparation, joint etail, properties, attributes, etc is correct

Thus, PMI is used as one of the easy method to check Base metal and weld metal to verify that the correct material is used. Positive Material Identification (PMI) is the analysis of a metallic alloy to establish composition by reading the quantities by percentage of its constituent elements. Typical methods for PMI include X-ray fluorescence (XRF) and optical emission spectrometry (OES).