Structure and Properties of Iron (Chromium Steel)–High-Carbon Ferrochrome Powder Composites

Abstract

The effect of production conditions on the phase composition, structure, and properties of powder materials made of iron and chromium steels (Kh17N2, Kh13M2) containing 35 wt.% ferrochrome (FKh800) was examined. The samples of composition (wt.%) 65Kh17N2–35FKh800, 65Kh13M2–35FKh800, and 65Fe–35FKh800 were prepared by single pressing and sintering in the range 1150–1270°C in vacuum involving isothermal holding for 30 min. The mixtures were preliminary ground in a ball mill in alcohol for 72 h. The high-carbon FKh800 ferrochrome powder (8.6 wt.% C) was prepared by mechanical grinding of the bulk material. The microstructure of the samples was studied using a REM-106I scanning electron microscope. The structure of the carbide steels was found to change from two-phase (when iron powder was used) to three-phase (when Kh13M2 and Kh17N2 chromium steel powders were used). The composition of the matrix phase insignificantly influenced the density and hardness of the carbide steels but slightly increased the bending strength of the Kh13M2-matrix composite. The materials were tested for abrasive wear resistance by dry shaft–plane friction against a diamond wheel. The mass wear of the carbide steels with an iron matrix was 2.1–2.4 times higher than that of the carbide steels with Kh13M2 and Kh17N2 matrices. Corrosion tests were performed with an accelerated method, in which the sample was periodically immersed into a 20% HNO3 solution. The samples with iron and Kh13M2 and Kh17N2 chromium steel matrices showed resistance in a nitric acid solution.