Spectroscopic monitoring during laser welding of aluminium alloy

The mechanical properties of aluminium alloys are strongly influenced by the alloying elements and their concentration. In the case of aluminium alloy EN AW-6060 the main alloying elements are magnesium and silicon. The first goal of this thesis was to determine stability, repeatability and sensitivity as figures of merit of the in-situ melt identification technique. In this study the emissions from the laser welding process were monitored with a spectrometer. With the information produced by the spectrometer, quantitative analysis was conducted to determine the figures of merit. The quantitative analysis concentrated on magnesium and aluminium emissions and their relation. The results showed that the stability of absolute intensities was low, but the normalized magnesium emissions were quite stable. The repeatability of monitoring magnesium emissions was high (about 90 %). Sensitivity of the in-situ melt identification technique was also high. As small as 0.5 % change in magnesium content was detected by the spectrometer. The second goal of this study was to determine the loss of mass during deep penetration laser welding. The amount of magnesium in the material was measured before and after laser welding to determine the loss of magnesium. This study was conducted for aluminium alloy with nominal magnesium content of 0-10 % and for standard material EN AW-6060 that was welded with filler wire AlMg5. It was found that while the magnesium concentration in the material changed, the loss of magnesium remained fairly even. Also by feeding filler wire, the behaviour was similar. Thirdly, the reason why silicon had not been detected in the emission spectrum needed to be explained. Literature research showed that the amount of energy required for silicon to excite is considerably higher compared to magnesium. The energy input in the used welding process is insufficient to excite the silicon atoms.

1,5 t. Ford (GAZ-AA)-sotasaaliskuorma-auton voitelukaava

kuv., 21 x 43 cm

Hinnasto Ford korin osista malli A & AA

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Hinnasto Ford vara-osista malli A & AA

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Ford tagavara osade hinnakiri mud. AA

kuv., 9 x 14 cm

Reservdelskatalog Ford modell AA

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Kerede osade hinnakiri Ford "A" ning "AA" mudelid

kuv., 13 x 22 cm

Koriosaluettelo Ford mallit A ja AA

kuv., 13 x 21 cm

Hinnasto Ford vara-osista malli AA

kuv., 10 x 15 cm

Varaosaluettelo Ford malli A ja AA

kuv., 14 x 21 cm

Ford varaosaluettelo malli A ja AA

kuv., 14 x 21 cm

Ford varaosaluettelo malli A ja AA

kuv., 14 x 21 cm

Ford osade nimestik mudel A ja AA

kuv., 14 x 22 cm

Ford hinnasto vara-osista malli A & AA

kuv., 10 x 15 cm