抄録
The mechanical properties of cast iron are mainly affected by the condition of precipitated graphite and matrix, and high temperature properties of cast iron are controlled by many phenomena including growth, oxidation, thermal shock, thermal fatigue and high temperature creep. In this experiment, flake graphite cast iron with different chemical compositions and heat treatment cycles and black heart malleable cast iron with different chemical compositions were transformed under constant load at constant temperature in vacuum. Transformation behavior, solidification structure and tensile fracture were observed by using optical, high temperature and scanning electron microscope.
Malleable cast iron was found to be superior to gray cast iron with respect to high temperature creep properties. In gray cast iron, precipitated graphite directly contribute to the origination and propagation of crack and progress of destruction. On the other hand, in malleable cast iron the crack occurs among the grain boundary of ferrite or pearlite grains and propagates. Precipitated graphites have an indiret influence on the transformation.
