Magnetic properties, internal friction at acoustical frequencies Q(-1), increment in the resonance frequency Delta F-r, and the linear magnetostriction lambda as functions of an applied magnetic field were measured for annealed and cold-worked NK alloy as well as for annealed armco iron, cobalt, nickel, permendur, and nivco 10 alloy. The correlation between the Q(-1)(H) dependences and magnetization processes was analyzed.