Abstract
The paper presents the results of complex studies of the influence of chemical composition and cooling rate of metal in the casting mold and heat treatment on the phase composition, structure, wear resistance, mechanical properties of white chromium, vanadium and chromovanadium cast irons. In the study of wear resistance of hardened chromium cast irons cast in sandy-clay mold, it is shown that the maximum resistance is observed at a carbon content of 2.8...3.2% (which is close to eutectic). Increase in carbon content above these limits reduces wear resistance due to the embrittlement effect of zaeutectic carbides (Fe, Cr)7C3. It follows from the results of the study that chromium cast irons containing 2.8...3.1% carbon and 18-24% chromium and hardened to maximum hardness have high hardness (64-65 HRC) and wear resistance. Introduction of a small amount of vanadium (up to 3%) into chromium cast irons increases the maximum hardness of hardened cast irons by 1...3 HRC units due to the formation of dispersed high-hardness VC carbides. The hardness increases monotonically with increasing carbon concentration in the alloy. Cast irons containing 12...18% of chromium (up to 68 HRC) have the highest hardness. By means of heat treatment, it is possible to increase the hardness of cast irons. Since with the increase in hardness of the material will increase and its wear resistance in abrasive wear, it is appropriate to consider the effect of heat treatment on the hardness of chromium-vanadium cast irons of different compositions. The possibility of using these cast irons for the manufacture of wear-resistant products of metallurgical equipment is shown.
Keywords:
White chromium, chrome vanadium and vanadium cast irons, cooling conditions during solidification, thermal treatment, phase composition and structure of cast irons, eutectic, mechanical properties, wear resistance, micro hardness