IN-SITU MEASUREMENT OF DISSOLVED HYDROGEN DURING LOW PRESSURE DIE CASTINGrnOF ALUMINIUM

摘要

Hydrogen based microporosity is the primary source of defects inrnLow Pressure Die Cast (LPDC) aluminium wheels, and is one ofrnthe most difficult to control. The in-situ measurement of dissolvedrnhydrogen in molten aluminium in an LPDC holding furnace isrnchallenging and cannot be achieved by conventional methods suchrnas reduced pressure or circulating gas techniques. A new versionrnof the ALSPEK H probe for the electrochemical measurement ofrnhydrogen in aluminium has been developed, and is suitable forrndeployment in sealed environments. This article presents resultsrnachieved with the new probe under LPDC conditions at arncommercial foundry. The probe shows good measurementrnstability, even during the LPDC pressurised cycle, and respondsrnwell to changes in the hydrogen level.