TWI Industrial Member Report Summary 378/1988
By G J Carter
This project has examined the effect of changes in electrode formulation on fume emission rate and composition during manual metal arc (MMA) welding of stainless steel. The aim has been to identify changes in consumable formulation providing reduced fume emission rate and toxicity. Particular emphasis was placed on the evolution of chromium compounds because of their known hazards to health. The work programme was conducted using consumables which deposited BS 2926: 1984: 19.12.3.L (AWS 5.4-74 E316L) weld metal but it is anticipated that findings here will be applicable to consumables for other alloy types.
Assessment of fume emission rate was made using the Swedish fume box technique while fume composition was determined using X-ray fluorescence and 'wet' analytical techniques. Changes in consumable formulation which were studied included the effect of general electrode type, the influence of calcium fluoride/calcium carbonate ratio, the effects of deoxidation and variations in mating alkali metal content.