Abstract
An influence of a decreased Cr content on the microstructure of the highly
alloyed Cr-Ni cast steel, duplex type, melted under laboratory conditions,
was characterized in the paper. The microstructure investigations were
performed in the initial state and after the heat treatment (solution
annealing) at 1060°C as well as the phase transformation kinetics at
continuous cooling was measured. The wear resistance of the investigated
cast steel was tested and compared with the 24%Cr-5%Ni-2.5%Mo cast steel.
The Cr content decrease, in ferritic-austenitic cast steels (duplex), from
24-26%Cr to 18% leads to the changes of the castings
microstructure and eliminating of a brittle σ phase. In dependence of the
casting cooling rate, apart from ferrite and austenite, also fine
martensite precipitates occur in the casting structure. It was shown that the
investigated cast steel is characterised by a slightly lower wear
resistance than the typical cast steel duplex grades.
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