Past efforts of the Nigerian Railway Corporation to produce shoe brake
blocks locally have proved unsuccessful; the brake blocks produced ar
e defective, and are highly susceptible to brittle (catastrophic) fail
ure. The objective of this work was to undertake failure analysis of l
ocally produced shoe blocks, and to design a metallurgical process to
produce efficient ones. To this end, mechanical and microstructural an
alyses of samples of the standard. failed and cast shoe blocks were ca
rried out. The result of the investigations reveals that the standard
brake block is nodular (graphitic) cast-iron, the failed block is cast
-iron with combined carbon (cementite), and the cast block is cast-iro
n with graphite flakes. The cast block can be upgraded to the standard
through appropriate inoculation of the melt if permanent mould castin
g facilities have to be employed. (C) 1997 Elsevier Science Ltd.