CHANGE IN MICROSTRUCTURE AND MECHANICAL-P ROPERTIES OF FE-30CR-5AL ALLOY WITH REDUCTION IN CARBON CONTENT

In order to obtain useful information about the improvement of mechani cal properties of Fe-30 mass%Cr-5 mass%Al alloys with decrement carbon content, on Fe-30Cr-5Al alloy whose carbon content decreased to 3.0 x 10(-3) mass% was produced. Some examinations were made on this alloy, as-cast and as-rolled, using various techniques such as the tensile t est, hardness test, optical microscopy and electron prove microanalysi s. The results are summarized as follows: (1) The precipitation amount of Cr23C6 decreases and mechanical properties are improved with decre ment of carbon content. By decreasing carbon content to 3.0 x 10(-3) m ass%, the tensile strength and elongation of this as-cast alloy are 40 0 MPa and 2 approximately 3%, respectively. (2) The grain size of this alloy decreased with increasing reduction in cold-rolling. However, t he grain size less than 350 mum does not affect the mechanical propert ies of this alloy. (3) The tensile strength and elongation of this as- hot-rolled alloy are 750 MPa and 30%, respectively. (4) Critical reduc tion per 1 pass without cracking increases with decrement in carbon co ntent.