Investigations into the production of dangerous substances during inert gas metal arc welding of nickel and nickel based alloys

Status:

completed 06/1996

Aims:

During inert gas metal arc welding (MIG) of nickel and nickel based alloys welding fume is produced which, depending upon the materials employed, contains different proportions of nickel oxides. Nickel oxides are classified as category 1 carcinogenic. Goal: determining the level of hazardous substances during MIG welding of nickel/nickel alloys depending upon material and process parameters.

Activities/Methods:

Measurement of emission and immission concentrations and chemical analysis of the composition of welding smoke with various additional welding materials, basic materials, inert gases, types of arc and electrode diameters.

Results:

The quantity and composition of welding fume are dependent upon all the examined parameters. The smallest relative quantities of hazardous substances occur with pure argon and pulse technique. During MIG welding of pure nickel with argon-helium-carbon dioxide the nickel content in the welding fume reaches 87 %. During immission measurements (in the breathing zone of a mannequin) the limit value for nickel oxide is clearly exceeded. Lower welding fume emmissions occur during TIG welding, the TRK value for nickel oxide in the breathing zone falls predominantly below the limit value.

Publications:

Mitteilungsblatt "Gesund und sicher" der Norddeutschen Metall-Berufsgenossenschaft 12/96, S. 371

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