58
K. Santhy and D. R. Rajkumar
Fig. 3 Some of defects present in cast products
due to defects in the components is listed in Table 1. The raw materials such as
cast iron and sand play a vital role. Hence, the qualities of foundry sand studied by
various test as per Indian standard [8]. The sand which is used for casting should have
specific properties at low and high temperatures. It is extremely critical and affects
the casting quality. Including refractoriness of sand measured in terms of pyrometric
cone equivalence. At design point of view sprue, runner, and gate ratio are compared
with Indian and ASM standards. The chemical composition of cast iron before and
after inoculants addition is studied using spectroscopy. In addition, microstructure
Table 1 Rejection rate (in
%) of products based on
various defects
Defects
% of rejection
Harvester cup Chain link Non-return valves
Sand pour
15
15
Sand crush
15
15
Veining defect 5
5
Porosity
10
10
Sand burn
13
Mismatch
9
Blow holes
5
Run out
3