Control of exposure to hexavalent chromium concentration in shielded metal arc welding fumes by nano-coating of electrodes

摘要

BackgroundCr(VI) is a suspected human carcinogen formed as a by-product of stainless steel welding. Nano-alumina and nano-titania coating of electrodes reduced the welding fume levels.ObjectiveTo investigate the effect of nano-coating of welding electrodes on Cr(VI) formation rate (Cr(VI) FR) from a shielded metal arc welding process.MethodsThe core welding wires were coated with nano-alumina and nano-titania using the sol-gel dip coating technique. Bead-on plate welds were deposited on SS 316 LN plates kept inside a fume test chamber. Cr(VI) analysis was done using an atomic absorption spectrometer (AAS).ResultsA reduction of 40% and 76%, respectively, in the Cr(VI) FR was observed from nano-alumina and nano-titania coated electrodes. Increase in the fume level decreased the Cr(VI) FR.DiscussionIncrease in fume levels blocked the UV radiation responsible for the formation of ozone thereby preventing the formation of Cr(VI).