Two criteria have been taken into account when considering a test as valid cut. First, a visual inspection is carried out to ensure that no burrs, pittings or uncut areas are present along the cutting area. Second, check that top kerf variation is less than 10% of mean value. Thus, tests have been classified into three groups: valid cuts, non-valid cuts and cut with pittings (when small pittings or material projections are present in the cutting areas).