Secondary hardness of alloy white irons

This paper describes an investigation of the phase composition, structure, and hardness of hardened and tempered white irons alloyed with chromium and molybdenum. The selection of the optimum (from the point of view of secondary hardness) hardening temperature was made on 15 X 15 mm disk specimens of 4Kh16 iron. The results of this investigation of a large number of heats of white iron containing 2.53.5% C, from 0 to 30% Cr, and 0.5% Mo showed that the maximum secondary hardness may be obtained in tempering of irons containing 5-10% Cr hardened from 11000C. With an increase in molybdenum content in the experimental chromium irons the area of appearance of the maximum hardness shifts to higher temperatures and the interval of these temperatures is broadened. It is found that the secondary hardness of chromium white irons is determined by the quantity of residual austenite in the hardened condition and its decomposition in tempering