Correct procedure to take readings for ferrite control in a weld bead

[marceloafo]

What is the correct procedure for measure the ferrite content in stainless steel a weld bead? Should we grind flat the spot for the probe fit or is there no problems to take the readings on a weld bead without flattening? Can the grinding change phase and modify the readings?

I am asking beacause i performed this experiments and realized even after a light grinding in the weld bead it is noticed an increase in the readings % (it was 8 and turned 12)

 

[metengr]

The correct procedure is based on the type of instrument you use and their instructions! For example, see the attachment. I have seen these used directly on as-welded surfaces. There is no surface prep required.

http://www.helmut-fischer.com/globalfiles/DE_Feritscope_EN.pdf