SOLIDIFICATION PATTERN OF HYPOEUTECTIC GREY CAST IRONS IN WEDGE TEST SAMPLES

Wedges of the type W, specified in the ASTM A 367-wedge test, are usually used to evaluate the chilling tendency of hypoeutectic grey cast irons. The parameters relative clear chill, relative mottled chill and relative total chill were introduced to compare chill sensitiveness of irons at different cooling modulus samples (0.1-0.4 cm) and as inoculation influence, at proper Mn, S and, Al content in final cast irons. Both cooling rate and inoculation are important and expected influencing factors, but a number of particular trends in the chill sensitiveness could also be identified. The difference between un-inoculated and inoculated irons increases from clear chill, through mottled area up to the total chill evaluation, especially for the higher cooling rate solidification conditions. It appears to be a difference as chill properties evaluation, for inoculated irons, as macro-and micro-analyses. Low chilling resulted at proper Mn, S and Al content [(%Mn) x (%S) = 0.04 and 0.005%Al] inclusively at low inoculant addition rate.