· Aleaciones ligeras ·
G.L. Datta and D. Benny Karunakar
Mechanical Engg. Dept., IIT, Kharagpur, India
67th World Foundry Congress
Hot tearing in certain cast metals continues to bother metal casters. A
number of casting parameters affect the susceptibility to hot tearing.
Experiments were conducted on Al-1%Sn alloys. Al-1%Sn is a high
freezing range alloy known to be extremely prone to hot tear cracking.
Effects of grain refinement and presence of iron and nickel have been
investigated by making use of a ring type casting with a steel core. Al-5Ti-
1B was used as the grain refiner. Optical and scanning electron
microscopy was used in the study. The results showed that contrary to
some published work, grain refinement alone could not eliminate hot
tearing. Average hot tear length decreased with increased grain
refinement and the minimum being achieved was at 5% by weight of Al-
5Ti-1B addition. Both iron and nickel have positive effects in minimizing
hot tear formation. SEM studies have shown that with iron there is an Al-
Sn-Fe rich phase in the form of a leaf like structure believed to be
providing anchorage to the adjacent grains and thus overcoming hot tear.
