The contact fatigue and the wear of DADI class aluminum cast iron

Abstract

In the present work there are given the results of experimental investigations of contact fatigue and the wear of deformable high strength ADI (DADI) class aluminum cast iron depending on the phase ratio in metallic matrix. It is shown that: Modification of cast iron melt with the magnesium vapor gives the opportunity the low silica (0.5–0.7% Si) high strength cast iron to be received, in which the concentration of sulfur will not exceed 0.002%. Besides, the type and degree of austenite transformation of the received cast iron can easily be varied so that required ratio of phase components such as upper bainite, lower bainite, martensite, carbide and the retained austenite could be provided in the metallic matrix and therefore the hardness in the range of 30-57HRC can be given. The wear rolling and rolling with creep tests carried out on the specimens tempered till different levels of hardness showed strong dependence of contact fatigue and the wear on the amount of retained austenite in the samples with optimal ratio, required for keeping the high wear resistance of wearing surfaces, of bainite and martensite phase components in the matrix structure. The stated parameters of the contact fatigue and the wear gives us reason to treat the high strength DADI class aluminum cast iron as an efficient substitute for the expensive steel as a constructional material for manufacturing the critical parts for high pressure multistep gas pumping compressors.