INFLUENCE OF HEAT TREATMENT CONDITIONS ON CHROMIUM ALLOYED CAST IRON PROPERTIES
Abstract
The article deals with finding out effects of heat treatment conditions of white chrome cast iron upon values of HRC hardness. Castings from such cast iron are specified for products required extreme abrasion wear resistance and that are used in oil mining and cement production industries.
Experiments were carried out on castings of spheres with 90 mm in diameter made from abrasion-resistant white cast iron with chemical composition of C=2.2%, Mn=1.2% and Cr=18.5%. We investigated the effect of hardening temperature ranging from 950°C to 1050°C and tempering temperature from 200°C up to 600°C.
The process of cooling from the hardening temperature was performed by means of compressed air. Results showed that the given cast iron is hardenable well by the air flow and acceptable values of HRC hardness were obtained for both surface and cross-section areas in entire range of hardening temperatures observed.
The substantial decrease in hardness was found out at the tempering temperature above 550°C. From the practical point of view it is possible to use the range of hardening temperature from 950°C to 1050°C and tempering temperatures up to 500°C for cast irons of such a quality.
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