PMI results 316L welds
PMI results 316L welds
(OP)
Having a problem with low nickel in the welds scanning with a XRF spectrometer. Checked pipe and it is around 10.5-11.0 and undiluted filler metal is 11.5-12 which matches the certs that were provided (we require actual chemistries). When we check the welded joints we are getting 8.75 to 10.5 with the majority of readings around 9.5. The pipe sizes are 3/4"-3" sch 40. I was expecting the values to be at least around 11 for the weld metal since there is dilution. I checked some 304L pipe and everything scanned OK. I even had one welded up in front of me and got the same results after welding. Scanner is calibrated, new battery, and we checked it on some other known parts. All reading look normal which makes me believe the scanner is working correctly. Any suggestions??





RE: PMI results 316L welds
RE: PMI results 316L welds
The seeming loss of nickel would be a puzzle. A comparison of melting / boiling points might shed some understanding.
Nickel Ni 1455 deg C melting, 2730 deg C boiling,
Iron Fe 1539 deg C melting, 2740 deg C boiling,
Chromium Cr 1890 deg C melting, 2500 deg C boiling,
Molybdenum Mo 2625 deg C melting, 4800 deg C boiling.
It might explain nickel losses by spattering, or its separation into concentrated islands or strata in the weld puddle. Nickel having slightly higher density than Cr-Fe might also tend to settle with Mo to bottom of the weld puddle?
RE: PMI results 316L welds
RE: PMI results 316L welds
RE: PMI results 316L welds
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RE: PMI results 316L welds
RE: PMI results 316L welds
RE: PMI results 316L welds
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RE: PMI results 316L welds
RE: PMI results 316L welds
RE: PMI results 316L welds
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